@RequestMapping("/save")
public void save(){
    System.out.println("user save ...");
}

@RequestMapping("/save")
@ResponseBody
public String save(){
    System.out.println("user save ...");
    return "{'info':'springmvc'}";
}

package site.hikki.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;

@Configuration
@ComponentScan(value="site.hikki", // 方法二
        excludeFilters = @ComponentScan.Filter(
                type = FilterType.ANNOTATION,
                classes = Controller.class
        )
)
public class SpringConfig {
}

package site.hikki.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("student")
public class ControllerStudent {

    @RequestMapping("findByNum")
    @ResponseBody
    public String findByNum(Integer num){
        System.out.println("findByNum===>"+num);
        return "findByNum===>"+num;
    }

    @RequestMapping("find")
    @ResponseBody
    public String findAll(){
        System.out.println("ControllerStudent findAll..");
        return "return ControllerStudent findAll..";
    }

    @RequestMapping("add")
    @ResponseBody
    public String add(Integer num,String name,String age,String major){
        System.out.println("findByNum===>"+num);
        System.out.println("name===>"+name);
        System.out.println("age===>"+age);
        System.out.println("major===>"+major);
        return "return ControllerStudent add..";
    }
}

@Override
protected Filter[] getServletFilters() {
    CharacterEncodingFilter filter = new CharacterEncodingFilter();
    filter.setEncoding("UTF-8");
    return new Filter[]{filter};
}

package site.hikki.entity;

public class Student {
    private Integer 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 Integer getNum() {
        return num;
    }

    public void setNum(Integer 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;
    }
}

//POJO参数传递
//嵌套POJO参数：嵌套属性按照层次结构设定名称即可完成参数传递
@RequestMapping("pojo")
@ResponseBody
public String pojo(Student student){
    System.out.println(student);
    return "student===>"+student;
}

package site.hikki.entity;

public class Grade {
    private String discipline;
    private double score;

    @Override
    public String toString() {
        return "Grade{" +
                "discipline='" + discipline + '\'' +
                ", score=" + score +
                '}';
    }

    public String getDiscipline() {
        return discipline;
    }

    public void setDiscipline(String discipline) {
        this.discipline = discipline;
    }

    public double getScore() {
        return score;
    }

    public void setScore(double score) {
        this.score = score;
    }
}

private Grade grade;

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

   public Grade getGrade() {
       return grade;
   }

   public void setGrade(Grade grade) {
       this.grade = grade;
   }

//POJO嵌套POJO参数传递
@RequestMapping("pojoinpojo")
@ResponseBody
public String pojoinpojo(Student student){
    System.out.println(student);
    return "student===>"+student;
}

//数组类型参数传递
//数组参数：同名请求参数可以直接映射到对应名称的形参数组对象中
@RequestMapping("/array")
@ResponseBody
public String arrayParam(String[] likes){
    System.out.println("数组参数传递 likes ==> "+ Arrays.toString(likes));
    return "{'likes':'"+ Arrays.toString(likes) +"'}";
}

//集合参数：同名请求参数可以使用@RequestParam注解映射到对应名称的集合对象中作为数据
@RequestMapping("/list")
@ResponseBody
public String listParam(@RequestParam List<String> likes){
    System.out.println("集合参数传递 likes ==> "+ likes);
    return "{'likes':'"+ likes +"'}";
}

package site.hikki.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
@ComponentScan(value = "site.hikki")
@EnableWebMvc //开启自动转换json数据的支持
public class SpringMvcConfig {
}

@RequestMapping("/jsonobject")
@ResponseBody
public String jsonObject(@RequestBody Student student){
    System.out.println("json参数传递 student ==> "+ student);
    return "{'student':'"+ student +"'}";
}

package site.hikki.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
@ComponentScan(value = "site.hikki")
@EnableWebMvc //开启自动转换json数据的支持
public class SpringMvcConfig {
}

//3. json数组对象嵌套
@RequestMapping("/jsonobjectarray")
@ResponseBody
public String jsonObjectArray(@RequestBody List<Student> student){
    System.out.println("json参数传递 student ==> "+ student);
    return "{'student':'"+ student +"'}";
}

//2. 响应文本数据
@RequestMapping("/toText")
@ResponseBody
public String toText(){
    System.out.println("响应文本数据");
    return "response Text";
}

//3. 响应POJO类型数据
@RequestMapping("/toPOJO")
@ResponseBody
public Student toEntity(){
    System.out.println("响应实体类，也就是POJO");
    Student student=new Student();
    student.setName("小码同学");
    student.setAge("20");
    student.setMajor("计算机科学与技术");
    student.setNum(2040811177);
    return student;
}

//4. 响应POJO集合对象
@RequestMapping("/toEntityList")
@ResponseBody
public List<Student> toEntityList(){
    Student student = new Student();
    student.setNum(2040811177);
    student.setName("小码同学");
    student.setAge("20");
    student.setMajor("计算机科学与技术");

    Student student1 = new Student();
    student1.setNum(2040800000);
    student1.setName("吴小白");
    student1.setAge("28");
    student1.setMajor("物联网");
    ArrayList<Student> list = new ArrayList<>();
    list.add(student);
    list.add(student1);
    return list;
}