JavaWeb实体类转为json对象的实现方法

package com.neuedu.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

/**
 * Keafmd
 *
 * @ClassName: User
 * @Description: user实体类
 * @author: 牛哄哄的柯南
 * @date: 2020-12-17 14:08
 */

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {

  private Integer id;
  private String name;
  private String address;
  private Date date;

}

<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>fastjson</artifactId>
   <version>1.2.73</version>
</dependency>

package com.neuedu.entity;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializerFeature;
import org.junit.Test;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * Keafmd
 *
 * @ClassName: Test
 * @Description: user测试类
 * @author: 牛哄哄的柯南
 * @date: 2020-12-17 14:10
 */

public class JsonTest {

  @Test
  public void test(){
    List userList = new ArrayList();
    userList.add(new User(1,"牛哄哄的柯南1","某某省某某市1",new Date()));
    userList.add(new User(2,"牛哄哄的柯南2","某某省某某市2",new Date()));
    userList.add(new User(3,"牛哄哄的柯南3","某某省某某市3",new Date()));
    userList.add(new User(4,"牛哄哄的柯南4","某某省某某市4",new Date()));
    userList.add(new User(5,"牛哄哄的柯南5","某某省某某市5",new Date()));
    userList.add(new User(6,"牛哄哄的柯南6","某某省某某市6",new Date()));


    //List集合转换成 json


    String json = JSON.toJSONString(userList,  SerializerFeature.WriteDateUseDateFormat );


    System.out.println(json);

  }
}

package com.neuedu.controller;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.neuedu.entity.User;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
 * Keafmd
 *
 * @ClassName: UserController
 * @Description: UserController
 * @author: 牛哄哄的柯南
 * @date: 2020-12-17 14:20
 *
 *
 * http://127.0.0.1:8080/web/user
 */

@WebServlet(name="UserController" ,urlPatterns = "/user")
public class UserController extends HttpServlet {

  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    List userList = new ArrayList();
    userList.add(new User(1,"牛哄哄的柯南1","某某省某某市1",new Date()));
    userList.add(new User(2,"牛哄哄的柯南2","某某省某某市2",new Date()));
    userList.add(new User(3,"牛哄哄的柯南3","某某省某某市3",new Date()));
    userList.add(new User(4,"牛哄哄的柯南4","某某省某某市4",new Date()));
    userList.add(new User(5,"牛哄哄的柯南5","某某省某某市5",new Date()));
    userList.add(new User(6,"牛哄哄的柯南6","某某省某某市6",new Date()));

    String json = JSON.toJSONString(userList,  SerializerFeature.WriteDateUseDateFormat  );


    resp.setContentType("application/json");
    resp.setCharacterEncoding("utf-8");
    PrintWriter out = resp.getWriter();
    out.write(json);
    out.flush();
    out.close();

  }

  @Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    this.doGet(req, resp);
  }
}