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【spring系列】4-Spring整合Mybatis+Junit4

282315分钟2023-01-1014未知

{% note pink ‘fas fa-umbrella-beach’ simple %}

本次实验使用的MariaDB数据库，不使用MySQL，两者的使用方式是一样的，如果你电脑没有安装MariaDB，你应该先去安装。

{% endnote %}

添加数据库

{% note pink ‘fas fa-download’ simple %}

数据库sql文件在项目的根目录下，自行添加到数据库。

项目下载地址：https://rookie1679.lanzoum.com/id5Rn0kn6z5a

{% endnote %}

添加依赖

xml

<!--    mariadb数据库-->
    <dependency>
      <groupId>org.mariadb.jdbc</groupId>
      <artifactId>mariadb-java-client</artifactId>
      <version>3.1.0</version>
    </dependency>
<!--    数据库连接池管理器-->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.2.15</version>
    </dependency>
<!--    mybatis-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.7</version>
    </dependency>
<!--    spring-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
<!--    spring管理jdbc-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
<!--    mybatis整合spring-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.0</version>
    </dependency>

项目结构

yaml

E:.
├─java
│  └─site
│      └─hikki
│          │  App.java # 程序入口
│          │
│          ├─config # 配置包
│          │      JdbcConfig.java
│          │      MybatisConfig.java
│          │      SpringConfig.java
│          │
│          ├─entity # 实体类
│          │      Student.java
│          │
│          ├─mapper # 数据层
│          │      StudentMapper.java
│          │ 
│          └─service # 服务层
│              │  StudentService.java
│              │
│              └─impl
│                      StudentServiceImpl.java
│
└─resources # 项目资源
        jdbc.properties # 数据库连接信息

新建数据库连接信息

在resource下新建jdbc.properties文件，并写入数据库连接信息。

{% note pink ‘fas fa-tty’ simple %}

username和password根据你自己电脑数据库用户来填写。

{% endnote %}

properties

jdbc.driver=org.mariadb.jdbc.Driver
jdbc.url=jdbc:mariadb://localhost:3307/spring_db?useSSL=false
jdbc.username=root
jdbc.password=root

设置配置

{% note blue ‘fas fa-vest-patches’ simple %}

在Spring项目中，我们首先是配置bean对象，好比我们之前使用xml文件时，我们创建好Spring项目时，也是先去新建SpringConfig.xml文件一样。配置完主配置(SpringConfig)类，还要配置第三方类(Mybatis)，还有Jdbc配置类。

{% endnote %}

主配置类

{% note blue ‘fas fa-volcano’ simple %}

配置主配置类，再导入第三方的配置类，分清主次，后续项目开发的结构会清晰很多。

{% endnote %}

@Configuration：表明该配置是配置类
@ComponentScan：表示扫描bean的范围，如果需要添加bean，则将bean对应的类放到扫描范围即可，如果有多个包，可以使用{param,param}数组进行分隔开。
@PropertySource：加载properties资源文件
@Import：导入第三方的bean，有多个用数组分隔开。

java

package site.hikki.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.PropertySource;
@Configuration //设置该类是配置类
@ComponentScan("site.hikki.service") //扫描bean范围
@PropertySource("classpath:jdbc.properties") //导入properties文件
@Import({JdbcConfig.class, MybatisConfig.class}) // 导入第三方的bean
public class SpringConfig {
}

Jdbc配置类

{% note blue ‘fas fa-volleyball-ball’ simple %}

我们在连接数据库时，用到了阿里巴巴开源的Druid连接池。

{% endnote %}

java

package site.hikki.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;
public class JdbcConfig {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

//    第三方bean管理
    @Bean
    public DataSource dataSource(){
        DruidDataSource ds = new DruidDataSource();
        ds.setDriverClassName(driver);
        ds.setUrl(url);
        ds.setUsername(username);
        ds.setPassword(password);
        return ds;
    }
}

Mybatis配置类

{% note red ‘fa-solid fa-arrows-to-dot’ simple %}

我们以前在使用mybatis时，我们都是使用Mybatis-Config.xml这么一个文件来管理我们的数据库连接，文件标签一大堆，总感觉很麻烦，Spring的出现，可以很好的帮我们解决这个问题，我们以前使用标签设置某个属性的值，现在可以直接调用某个方法来设置，设置起来方便许多。

{% endnote %}

mybatis配置文件关键的几个配置项一般就加载properties文件、配置包别名、配置数据库连接信息、扫描mapper位置等等。

配置包别名 & 加载数据库连接信息

创建一个SqlSessionFactoryBean方法，所有配置信息都在该方法下进行设置。
加载jdbc.properties文件，我们在主配置已经加载好了，所以这里就不需要重配置了。
<typeAliases>下的包标签我们使用setTypeAliasesPackage方法来实现，如果想对某个类来实现别名，我们可以使用setTypeAliases来实现对类进行别名。
加载数据库信息，我们使用setDataSource来实现，dataSource是第三方的bean，是JdbcConfig配置类下的一个方法，我们可以在该方法中直接添加参数，Spring会帮我们自动注入。

扫描mapper位置

mapper的扫描范围我们需要用到MapperScannerConfigurer方法，对MapperScannerConfigurer()实例化，添加mapper包的位置。

案例代码：

java

package site.hikki.config;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;
import javax.sql.DataSource;

public class MybatisConfig {

    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource){
        SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();
        ssfb.setTypeAliasesPackage("site.hikki.entity");
        ssfb.setDataSource(dataSource);
        return ssfb;
    }

    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer(){
        MapperScannerConfigurer msc = new MapperScannerConfigurer();
        msc.setBasePackage("site.hikki.mapper");
        return msc;
    }
}

实体类

java

package site.hikki.entity;

public class Student {
    private String num;
    private String name;
    private String age;
    private String major;
    @Override
    public String toString() {
        return "Student{" +
                "num='" + num + '\'' +
                ", name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", major='" + major + '\'' +
                '}';
    }

    public String getNum() {
        return num;
    }

    public void setNum(String num) {
        this.num = num;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getMajor() {
        return major;
    }

    public void setMajor(String major) {
        this.major = major;
    }
}

编写mapper

在site.hikki.mapper包下新建一个StudentMapper接口，写入内容如下：

java

package site.hikki.mapper;

import org.apache.ibatis.annotations.*;
import site.hikki.entity.Student;

import java.util.List;

public interface StudentMapper {
    /**
     * 查询全部学生信息
     * @return
     */
    @Select("select * from tb_student")
    List<Student> find();

    /**
     * 根据num查询学生信息
     * @param num
     * @return
     */
    @Select("select * from tb_student where num=#{num}")
    Student findByNum(@Param("num") String num);

    /**
     * 添加学生信息
     * @param student
     * @return
     */
    @Insert("insert into tb_student (num,name,age,major) value(#{num},#{name},#{age},#{major})")
    int addStudent(Student student);

    /**
     * 根据num删除学生信息
     * @param num
     * @return 返回更新条数
     */
    @Delete("delete from tb_student where num =#{num}")
    int delStudentBynum(@Param("num") String num);

    /**
     * 根据num更新姓名
     * @param num
     * @param name
     * @return
     */
    @Update("update tb_student set name = #{name} where num = #{num}")
    int updateStudentBynum(@Param("name") String name, @Param("num") String num);
}

编写服务层

{% note blue ‘fa-solid fa-mug-hot’ simple %}

在site.hikki.service下编写服务层

{% endnote %}

服务层接口

java

package site.hikki.service;

import site.hikki.entity.Student;
import java.util.List;

public interface StudentService {
    List<Student> find();

    Student findByNum(String num);

    int addStudent(Student student);

    int delStudentBynum(String num);

    int updateStudentBynum(String name,String num);
}

实现方法

设置该服务类为bean(建议使用@Service)，如果没有指定bean名称，则默认使用studentService。
添加StudentMapper属性，并且配置自动注入
实现StudentService方法，并且返回StudentMapper的接口方法

我们添加了StudentMapper的属性，使用 @Autowired后会自动装配，好比以前使用new StudentMapper()是一样的，只是现在spring帮我们new了对象，不需要我们自己new了。

{% note pink ‘fas fa-water-rise’ simple %}

回顾之前学习内容：配置某类是bean对象，有三个注解都可以实现，三个注解表示的意思是一样的，我们常常将他们区分开始为了更好的理解代码，理解当前的bean是作用，提高开发效率。

@Controller：控制器(注入服务)。
@Repository：dao持久层（实现dao访问），标注数据访问组件。
@Service：service服务层（注入dao），处理业务逻辑。
@component：标注一个类为Spring容器的Bean，（把普通pojo实例化到spring容器中，相当于配置文件中的<bean id="" class=""/>）

{% endnote %}

java

package site.hikki.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import site.hikki.entity.Student;
import site.hikki.mapper.StudentMapper;
import site.hikki.service.StudentService;

import java.util.List;

@Service
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentMapper studentMapper;

    @Override
    public List<Student> find() {
        return studentMapper.find();
    }

    @Override
    public Student findByNum(String num) {
        return studentMapper.findByNum(num);
    }

    @Override
    public int addStudent(Student student) {
        return studentMapper.addStudent(student);
    }

    @Override
    public int delStudentBynum(String num) {
        return studentMapper.delStudentBynum(num);
    }

    @Override
    public int updateStudentBynum(String name, String num) {
        return studentMapper.updateStudentBynum(name,num);
    }
}

程序入口

按照以往的使用一样，加载主配置项，创建Ioc容器，获取到服务类的bean，然后调用服务类下的方法即可。

java

package site.hikki;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import site.hikki.config.SpringConfig;
import site.hikki.entity.Student;
import site.hikki.service.StudentService;
import java.util.List;

public class App {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);
        StudentService bean = ctx.getBean(StudentService.class);
        List<Student> students = bean.find(); // 查询全部学生信息
        for (Student s :students) {
            System.out.println(s);
        }
    }
}

{% note blue ‘fa-sharp fa-solid fa-question’ simple %}

在以前使用mybatis时，对数据进行增删改查时，我们都需要对SqlSession进行clone或者commit，但使用了spring就不需要这一步了，我猜想可能是我们使用SqlSessionFactoryBean时，spring帮我们实现了。

{% endnote %}

Junit4测试

导包

Spring有整合Junit测试的方法，方便我们进行项目测试。

首先我们先导入一些相关依赖：

xml

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>

测试步骤

步骤	方法	备注
第一步	@RunWith(SpringJUnit4ClassRunner.class)	设置类运行器
第二步	@ContextConfiguration(classes = SpringConfig.class)	运行环境
第三步	@Autowired private StudentService studentService;	引用类型注入
第四步	@Test public void find() {}	编写测试方法

{% note pink ‘fas fa-question-circle’ simple %}

注意：在导包时要导入import org.junit.Test，不要导错包了。

{% endnote %}

java

package site.hikki.service;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import site.hikki.config.SpringConfig;
import site.hikki.entity.Student;
import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class) //1.设置类运行器
@ContextConfiguration(classes = SpringConfig.class) // 2.运行环境
public class StudentServiceTest2 {
    
    @Autowired // 3. 引用类型注入
    private StudentService studentService;
    
    @Test // 4.编写测试方法
    public void find() {
        List<Student> students = studentService.find();
        for (Student s :students) {
            System.out.println(s);
        }
    }

    @Test
    public void findByNum() {
        Student student = studentService.findByNum("1");
        System.out.println(student);
    }

    @Test
    public void addStudent() {
        Student student = new Student();
        student.setName("小码同学");
        student.setAge("20");
        student.setMajor("计算机科学与技术");
        int i = studentService.addStudent(student);
        System.out.println(i);
    }

    @Test
    public void delStudentBynum() {
        int i = studentService.delStudentBynum("3");
        System.out.println(i);
    }

    @Test
    public void updateStudentBynum() {
        int i = studentService.updateStudentBynum("小码公众号叫：小码同学", "5");
        System.out.println(i);
    }
}

{% hideToggle 可能会遇到的错误 %}

{% tabs %}

错误1：java.lang.Exception: Method XXX() should be public

bash

java.lang.Exception: Method findByNum() should be public

**解决方法：**根据提示，在findByNum()方法前添加public即可

错误2：java.lang.Exception: No runnable methods

从错误中提炼出主要错误信息：

警告: Runner org.junit.internal.runners.ErrorReportingRunner (used on class site.hikki.service.StudentServiceTest2) does not support filtering and will therefore be run completely.
java.lang.Exception: No runnable methods
java.lang.NullPointerException

分析：

原因是导错了，原来导入的包是import org.junit.jupiter.api.Test;，junit版本对应错误你在pom里的junit和@Test的junit版本不一致在@Test时选择maven下的版本就可以了，不要选带api的，还有SpringJUnit4ClassRunner只支持4.12版本及以上。

解决方法：

将改import org.junit.jupiter.api.Test;为import org.junit.Test;即可正常运行

错误内容如下：

bash

1月 10, 2023 12:37:55 下午 org.junit.vintage.engine.descriptor.RunnerTestDescriptor warnAboutUnfilterableRunner
警告: Runner org.junit.internal.runners.ErrorReportingRunner (used on class site.hikki.service.StudentServiceTest2) does not support filtering and will therefore be run completely.

java.lang.Exception: No runnable methods

	at org.junit.runners.BlockJUnit4ClassRunner.validateInstanceMethods(BlockJUnit4ClassRunner.java:191)
	at org.junit.runners.BlockJUnit4ClassRunner.collectInitializationErrors(BlockJUnit4ClassRunner.java:128)
	at org.junit.runners.ParentRunner.validate(ParentRunner.java:416)
	at org.junit.runners.ParentRunner.<init>(ParentRunner.java:84)
	at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:65)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.<init>(SpringJUnit4ClassRunner.java:137)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
	at org.junit.vintage.engine.discovery.DefensiveAllDefaultPossibilitiesBuilder$DefensiveAnnotatedBuilder.buildRunner(DefensiveAllDefaultPossibilitiesBuilder.java:114)
	at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
	at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
	at org.junit.vintage.engine.discovery.DefensiveAllDefaultPossibilitiesBuilder.runnerForClass(DefensiveAllDefaultPossibilitiesBuilder.java:57)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
	at org.junit.vintage.engine.discovery.ClassSelectorResolver.resolveTestClass(ClassSelectorResolver.java:66)
	at org.junit.vintage.engine.discovery.ClassSelectorResolver.resolve(ClassSelectorResolver.java:47)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.lambda$resolve$2(EngineDiscoveryRequestResolution.java:134)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1632)
	at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:127)
	at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:502)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:488)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:543)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:185)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:125)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.access$100(EngineDiscoveryRequestResolution.java:57)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution$DefaultContext.resolve(EngineDiscoveryRequestResolution.java:224)
	at org.junit.vintage.engine.discovery.MethodSelectorResolver.resolveParentAndAddFilter(MethodSelectorResolver.java:56)
	at org.junit.vintage.engine.discovery.MethodSelectorResolver.resolve(MethodSelectorResolver.java:40)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.lambda$resolve$2(EngineDiscoveryRequestResolution.java:146)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1632)
	at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:127)
	at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:502)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:488)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:543)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:185)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:125)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolveCompletely(EngineDiscoveryRequestResolution.java:91)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.run(EngineDiscoveryRequestResolution.java:82)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolver.resolve(EngineDiscoveryRequestResolver.java:113)
	at org.junit.vintage.engine.discovery.VintageDiscoverer.discover(VintageDiscoverer.java:42)
	at org.junit.vintage.engine.VintageTestEngine.discover(VintageTestEngine.java:64)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discoverEngineRoot(EngineDiscoveryOrchestrator.java:152)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discoverSafely(EngineDiscoveryOrchestrator.java:134)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discover(EngineDiscoveryOrchestrator.java:108)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discover(EngineDiscoveryOrchestrator.java:80)
	at org.junit.platform.launcher.core.DefaultLauncher.discover(DefaultLauncher.java:110)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
	at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
	at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
	at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
	at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)


java.lang.NullPointerException
	at site.hikki.service.StudentServiceTest2.find(StudentServiceTest2.java:22)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:725)
	at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
	at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149)
	at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140)
	at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84)
	at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
	at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
	at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
	at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:214)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:210)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:66)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
	at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
	at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
	at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
	at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)

{% endtabs %}

{% endhideToggle %}

小码同学

生活明朗，万物可爱

本文是原创文章，采用 CC BY-NC-SA 4.0 协议，完整转载请注明来自小码同学

Java22

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【spring系列】4-Spring整合Mybatis+Junit4

282315分钟2023-01-1014未知

{% note pink ‘fas fa-umbrella-beach’ simple %}

本次实验使用的MariaDB数据库，不使用MySQL，两者的使用方式是一样的，如果你电脑没有安装MariaDB，你应该先去安装。

{% endnote %}

添加数据库

{% note pink ‘fas fa-download’ simple %}

数据库sql文件在项目的根目录下，自行添加到数据库。

项目下载地址：https://rookie1679.lanzoum.com/id5Rn0kn6z5a

{% endnote %}

添加依赖

xml

<!--    mariadb数据库-->
    <dependency>
      <groupId>org.mariadb.jdbc</groupId>
      <artifactId>mariadb-java-client</artifactId>
      <version>3.1.0</version>
    </dependency>
<!--    数据库连接池管理器-->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.2.15</version>
    </dependency>
<!--    mybatis-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.7</version>
    </dependency>
<!--    spring-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
<!--    spring管理jdbc-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
<!--    mybatis整合spring-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.0</version>
    </dependency>

项目结构

yaml

E:.
├─java
│  └─site
│      └─hikki
│          │  App.java # 程序入口
│          │
│          ├─config # 配置包
│          │      JdbcConfig.java
│          │      MybatisConfig.java
│          │      SpringConfig.java
│          │
│          ├─entity # 实体类
│          │      Student.java
│          │
│          ├─mapper # 数据层
│          │      StudentMapper.java
│          │ 
│          └─service # 服务层
│              │  StudentService.java
│              │
│              └─impl
│                      StudentServiceImpl.java
│
└─resources # 项目资源
        jdbc.properties # 数据库连接信息

新建数据库连接信息

在resource下新建jdbc.properties文件，并写入数据库连接信息。

{% note pink ‘fas fa-tty’ simple %}

username和password根据你自己电脑数据库用户来填写。

{% endnote %}

properties

jdbc.driver=org.mariadb.jdbc.Driver
jdbc.url=jdbc:mariadb://localhost:3307/spring_db?useSSL=false
jdbc.username=root
jdbc.password=root

设置配置

{% note blue ‘fas fa-vest-patches’ simple %}

{% endnote %}

主配置类

{% note blue ‘fas fa-volcano’ simple %}

配置主配置类，再导入第三方的配置类，分清主次，后续项目开发的结构会清晰很多。

{% endnote %}

@Configuration：表明该配置是配置类
@ComponentScan：表示扫描bean的范围，如果需要添加bean，则将bean对应的类放到扫描范围即可，如果有多个包，可以使用{param,param}数组进行分隔开。
@PropertySource：加载properties资源文件
@Import：导入第三方的bean，有多个用数组分隔开。

java

package site.hikki.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.PropertySource;
@Configuration //设置该类是配置类
@ComponentScan("site.hikki.service") //扫描bean范围
@PropertySource("classpath:jdbc.properties") //导入properties文件
@Import({JdbcConfig.class, MybatisConfig.class}) // 导入第三方的bean
public class SpringConfig {
}

Jdbc配置类

{% note blue ‘fas fa-volleyball-ball’ simple %}

我们在连接数据库时，用到了阿里巴巴开源的Druid连接池。

{% endnote %}

java

package site.hikki.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;
public class JdbcConfig {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

//    第三方bean管理
    @Bean
    public DataSource dataSource(){
        DruidDataSource ds = new DruidDataSource();
        ds.setDriverClassName(driver);
        ds.setUrl(url);
        ds.setUsername(username);
        ds.setPassword(password);
        return ds;
    }
}

Mybatis配置类

{% note red ‘fa-solid fa-arrows-to-dot’ simple %}

{% endnote %}

mybatis配置文件关键的几个配置项一般就加载properties文件、配置包别名、配置数据库连接信息、扫描mapper位置等等。

配置包别名 & 加载数据库连接信息

创建一个SqlSessionFactoryBean方法，所有配置信息都在该方法下进行设置。
加载jdbc.properties文件，我们在主配置已经加载好了，所以这里就不需要重配置了。
<typeAliases>下的包标签我们使用setTypeAliasesPackage方法来实现，如果想对某个类来实现别名，我们可以使用setTypeAliases来实现对类进行别名。
加载数据库信息，我们使用setDataSource来实现，dataSource是第三方的bean，是JdbcConfig配置类下的一个方法，我们可以在该方法中直接添加参数，Spring会帮我们自动注入。

扫描mapper位置

mapper的扫描范围我们需要用到MapperScannerConfigurer方法，对MapperScannerConfigurer()实例化，添加mapper包的位置。

案例代码：

java

package site.hikki.config;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;
import javax.sql.DataSource;

public class MybatisConfig {

    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource){
        SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();
        ssfb.setTypeAliasesPackage("site.hikki.entity");
        ssfb.setDataSource(dataSource);
        return ssfb;
    }

    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer(){
        MapperScannerConfigurer msc = new MapperScannerConfigurer();
        msc.setBasePackage("site.hikki.mapper");
        return msc;
    }
}

实体类

java

package site.hikki.entity;

public class Student {
    private String num;
    private String name;
    private String age;
    private String major;
    @Override
    public String toString() {
        return "Student{" +
                "num='" + num + '\'' +
                ", name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", major='" + major + '\'' +
                '}';
    }

    public String getNum() {
        return num;
    }

    public void setNum(String num) {
        this.num = num;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getMajor() {
        return major;
    }

    public void setMajor(String major) {
        this.major = major;
    }
}

编写mapper

在site.hikki.mapper包下新建一个StudentMapper接口，写入内容如下：

java

package site.hikki.mapper;

import org.apache.ibatis.annotations.*;
import site.hikki.entity.Student;

import java.util.List;

public interface StudentMapper {
    /**
     * 查询全部学生信息
     * @return
     */
    @Select("select * from tb_student")
    List<Student> find();

    /**
     * 根据num查询学生信息
     * @param num
     * @return
     */
    @Select("select * from tb_student where num=#{num}")
    Student findByNum(@Param("num") String num);

    /**
     * 添加学生信息
     * @param student
     * @return
     */
    @Insert("insert into tb_student (num,name,age,major) value(#{num},#{name},#{age},#{major})")
    int addStudent(Student student);

    /**
     * 根据num删除学生信息
     * @param num
     * @return 返回更新条数
     */
    @Delete("delete from tb_student where num =#{num}")
    int delStudentBynum(@Param("num") String num);

    /**
     * 根据num更新姓名
     * @param num
     * @param name
     * @return
     */
    @Update("update tb_student set name = #{name} where num = #{num}")
    int updateStudentBynum(@Param("name") String name, @Param("num") String num);
}

编写服务层

{% note blue ‘fa-solid fa-mug-hot’ simple %}

在site.hikki.service下编写服务层

{% endnote %}

服务层接口

java

package site.hikki.service;

import site.hikki.entity.Student;
import java.util.List;

public interface StudentService {
    List<Student> find();

    Student findByNum(String num);

    int addStudent(Student student);

    int delStudentBynum(String num);

    int updateStudentBynum(String name,String num);
}

实现方法

设置该服务类为bean(建议使用@Service)，如果没有指定bean名称，则默认使用studentService。
添加StudentMapper属性，并且配置自动注入
实现StudentService方法，并且返回StudentMapper的接口方法

{% note pink ‘fas fa-water-rise’ simple %}

@Controller：控制器(注入服务)。
@Repository：dao持久层（实现dao访问），标注数据访问组件。
@Service：service服务层（注入dao），处理业务逻辑。
@component：标注一个类为Spring容器的Bean，（把普通pojo实例化到spring容器中，相当于配置文件中的<bean id="" class=""/>）

{% endnote %}

java

package site.hikki.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import site.hikki.entity.Student;
import site.hikki.mapper.StudentMapper;
import site.hikki.service.StudentService;

import java.util.List;

@Service
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentMapper studentMapper;

    @Override
    public List<Student> find() {
        return studentMapper.find();
    }

    @Override
    public Student findByNum(String num) {
        return studentMapper.findByNum(num);
    }

    @Override
    public int addStudent(Student student) {
        return studentMapper.addStudent(student);
    }

    @Override
    public int delStudentBynum(String num) {
        return studentMapper.delStudentBynum(num);
    }

    @Override
    public int updateStudentBynum(String name, String num) {
        return studentMapper.updateStudentBynum(name,num);
    }
}

程序入口

按照以往的使用一样，加载主配置项，创建Ioc容器，获取到服务类的bean，然后调用服务类下的方法即可。

java

package site.hikki;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import site.hikki.config.SpringConfig;
import site.hikki.entity.Student;
import site.hikki.service.StudentService;
import java.util.List;

public class App {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);
        StudentService bean = ctx.getBean(StudentService.class);
        List<Student> students = bean.find(); // 查询全部学生信息
        for (Student s :students) {
            System.out.println(s);
        }
    }
}

{% note blue ‘fa-sharp fa-solid fa-question’ simple %}

{% endnote %}

Junit4测试

导包

Spring有整合Junit测试的方法，方便我们进行项目测试。

首先我们先导入一些相关依赖：

xml

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>

测试步骤

步骤	方法	备注
第一步	@RunWith(SpringJUnit4ClassRunner.class)	设置类运行器
第二步	@ContextConfiguration(classes = SpringConfig.class)	运行环境
第三步	@Autowired private StudentService studentService;	引用类型注入
第四步	@Test public void find() {}	编写测试方法

{% note pink ‘fas fa-question-circle’ simple %}

注意：在导包时要导入import org.junit.Test，不要导错包了。

{% endnote %}

java

package site.hikki.service;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import site.hikki.config.SpringConfig;
import site.hikki.entity.Student;
import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class) //1.设置类运行器
@ContextConfiguration(classes = SpringConfig.class) // 2.运行环境
public class StudentServiceTest2 {
    
    @Autowired // 3. 引用类型注入
    private StudentService studentService;
    
    @Test // 4.编写测试方法
    public void find() {
        List<Student> students = studentService.find();
        for (Student s :students) {
            System.out.println(s);
        }
    }

    @Test
    public void findByNum() {
        Student student = studentService.findByNum("1");
        System.out.println(student);
    }

    @Test
    public void addStudent() {
        Student student = new Student();
        student.setName("小码同学");
        student.setAge("20");
        student.setMajor("计算机科学与技术");
        int i = studentService.addStudent(student);
        System.out.println(i);
    }

    @Test
    public void delStudentBynum() {
        int i = studentService.delStudentBynum("3");
        System.out.println(i);
    }

    @Test
    public void updateStudentBynum() {
        int i = studentService.updateStudentBynum("小码公众号叫：小码同学", "5");
        System.out.println(i);
    }
}

{% hideToggle 可能会遇到的错误 %}

{% tabs %}

错误1：java.lang.Exception: Method XXX() should be public

bash

java.lang.Exception: Method findByNum() should be public

**解决方法：**根据提示，在findByNum()方法前添加public即可

错误2：java.lang.Exception: No runnable methods

从错误中提炼出主要错误信息：

警告: Runner org.junit.internal.runners.ErrorReportingRunner (used on class site.hikki.service.StudentServiceTest2) does not support filtering and will therefore be run completely.
java.lang.Exception: No runnable methods
java.lang.NullPointerException

分析：

解决方法：

将改import org.junit.jupiter.api.Test;为import org.junit.Test;即可正常运行

错误内容如下：

bash

1月 10, 2023 12:37:55 下午 org.junit.vintage.engine.descriptor.RunnerTestDescriptor warnAboutUnfilterableRunner
警告: Runner org.junit.internal.runners.ErrorReportingRunner (used on class site.hikki.service.StudentServiceTest2) does not support filtering and will therefore be run completely.

java.lang.Exception: No runnable methods

	at org.junit.runners.BlockJUnit4ClassRunner.validateInstanceMethods(BlockJUnit4ClassRunner.java:191)
	at org.junit.runners.BlockJUnit4ClassRunner.collectInitializationErrors(BlockJUnit4ClassRunner.java:128)
	at org.junit.runners.ParentRunner.validate(ParentRunner.java:416)
	at org.junit.runners.ParentRunner.<init>(ParentRunner.java:84)
	at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:65)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.<init>(SpringJUnit4ClassRunner.java:137)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
	at org.junit.vintage.engine.discovery.DefensiveAllDefaultPossibilitiesBuilder$DefensiveAnnotatedBuilder.buildRunner(DefensiveAllDefaultPossibilitiesBuilder.java:114)
	at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
	at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
	at org.junit.vintage.engine.discovery.DefensiveAllDefaultPossibilitiesBuilder.runnerForClass(DefensiveAllDefaultPossibilitiesBuilder.java:57)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
	at org.junit.vintage.engine.discovery.ClassSelectorResolver.resolveTestClass(ClassSelectorResolver.java:66)
	at org.junit.vintage.engine.discovery.ClassSelectorResolver.resolve(ClassSelectorResolver.java:47)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.lambda$resolve$2(EngineDiscoveryRequestResolution.java:134)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1632)
	at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:127)
	at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:502)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:488)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:543)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:185)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:125)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.access$100(EngineDiscoveryRequestResolution.java:57)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution$DefaultContext.resolve(EngineDiscoveryRequestResolution.java:224)
	at org.junit.vintage.engine.discovery.MethodSelectorResolver.resolveParentAndAddFilter(MethodSelectorResolver.java:56)
	at org.junit.vintage.engine.discovery.MethodSelectorResolver.resolve(MethodSelectorResolver.java:40)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.lambda$resolve$2(EngineDiscoveryRequestResolution.java:146)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1632)
	at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:127)
	at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:502)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:488)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:543)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:185)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:125)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolveCompletely(EngineDiscoveryRequestResolution.java:91)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.run(EngineDiscoveryRequestResolution.java:82)
	at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolver.resolve(EngineDiscoveryRequestResolver.java:113)
	at org.junit.vintage.engine.discovery.VintageDiscoverer.discover(VintageDiscoverer.java:42)
	at org.junit.vintage.engine.VintageTestEngine.discover(VintageTestEngine.java:64)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discoverEngineRoot(EngineDiscoveryOrchestrator.java:152)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discoverSafely(EngineDiscoveryOrchestrator.java:134)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discover(EngineDiscoveryOrchestrator.java:108)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discover(EngineDiscoveryOrchestrator.java:80)
	at org.junit.platform.launcher.core.DefaultLauncher.discover(DefaultLauncher.java:110)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
	at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
	at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
	at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
	at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)


java.lang.NullPointerException
	at site.hikki.service.StudentServiceTest2.find(StudentServiceTest2.java:22)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:725)
	at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
	at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149)
	at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140)
	at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84)
	at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
	at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
	at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
	at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:214)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:210)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:66)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
	at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
	at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
	at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
	at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)

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