将数据转换成json数据

Controller类

@Controller
public class UserController {

    @RequestMapping("/m1")
    public String m1(){
        System.out.println("进入m1方法....");
        return "m1";

    }
    //同步请求 返回页面和数据
    @RequestMapping("/m2")
    public ModelAndView m2(){
        ModelAndView mv = new ModelAndView();
        mv.addObject("msg","今天星期一");
        mv.setViewName("m1");
        return mv;

    }
    //异步请求 响应一个字符串
    @RequestMapping("/m3")
    public void m3(HttpServletResponse response) throws IOException {
        response.getWriter().println("hello,word");
    }
    //异步请求 响应一个对象
    @RequestMapping("/m4")
    public void m4(HttpServletResponse response) throws IOException {
        response.getWriter().println("{id:1,name:\"admin\",address:\"武汉\"}");
    }
//    通过jackjson将对象转换成json数据
    @RequestMapping("/m5")
    @ResponseBody//返回学生对象，转json
    public Student m5 (){
        Student student = new Student();
        student.setId(1);
        student.setName("admin");
        student.setAddress("wuhan");
        return student;
    }

    //将集合转换为json数据
    @RequestMapping("/m6")
    @ResponseBody//返回学生对象，转json
    public List<Student> list (){
        List<Student> list = new ArrayList<>();
        for(int i=1;i<=3;i++){
            Student s = new Student();
            s.setId(i);
            s.setName("admin"+i);
            s.setAddress("wuhan"+i);
        }
        return list;
    }
}

学生类

package com.hehe.controller;

/**
 * 学生类  alt+insert 快捷键
 */
public class Studnet {
    private  Integer id;//学号
    private  String name;//姓名
    private String address;//地址

 //toString方法
//get和set方法
}

配置文件

<!--配置json数据转换-->
<mvc:annotation-driven></mvc:annotation-driven>

依赖

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-core</artifactId>
  <version>2.11.0</version>
</dependency>
<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-databind</artifactId>
  <version>2.11.0</version>
</dependency>
<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-annotations</artifactId>
  <version>2.11.0</version>
</dependency>