后端json格式信息发送前端各种方法

1，后端代码

package wsh.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import wsh.pojo.User;

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

@RestController
public class userController {
//    对象信息发送
    @RequestMapping(value = "j1")
    public String json01() throws JsonProcessingException {
        ObjectMapper mapper=new ObjectMapper();
        User user=new User("版本",11,"猫猫");
        String str=mapper.writeValueAsString(user);
        return str;
    }
//    时间信息发送
    @RequestMapping(value = "j2")
    public String json02() throws JsonProcessingException {
//        获取json数据格式映射对象
        ObjectMapper mapper=new ObjectMapper();
//        关闭时间戳形式输出时间
        mapper.configure(SerializationFeature.WRITE_DATE_KEYS_AS_TIMESTAMPS,false);
//        自定义时间输出格式
        SimpleDateFormat format=new SimpleDateFormat("yyyy--MM--dd**HH-mm-ss");
//        设置json输出格式为自定义格式
        mapper.setDateFormat(format);
        Date date=new Date();
//        输出时间信息
        return mapper.writeValueAsString(date);
    }
//    集合信息发送
@RequestMapping(value = "j3")
public String json03() throws JsonProcessingException {
    ObjectMapper mapper=new ObjectMapper();
    User user=new User("版本",11,"猫猫");
    User use2=new User("版本",11,"猫猫");
    User use3=new User("版本",11,"猫猫");
    User use4=new User("版本",11,"猫猫");
    List<User> users=new  ArrayList();
    users.add(use2);
    users.add(use3);
    users.add(use4);
    users.add(user);
    String str=mapper.writeValueAsString(users);
    return str;
}
}

前端效果"2022--06--01**20-18-22"

{"userName":"版本","age":11,"description":"猫猫"}

[{"userName":"版本","age":11,"description":"猫猫"},{"userName":"版本","age":11,"description":"猫猫"},{"userName":"版本","age":11,"description":"猫猫"},{"userName":"版本","age":11,"description":"猫猫"}]