JSON

JSON(JavaScript Object Notation，JS标记对象)是一种轻量级的数据交换格式。

1、jackson

导入依赖

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.12.0</version>
</dependency>

Utils工具类

package com.sw.utils;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

import java.text.SimpleDateFormat;

/**
 * @Author suaxi
 * @Date 2020/12/17 16:08
 */

public class JsonUtils {

    public static String getJson(Object object){
        return getJson(object,"yyyy-MM-dd HH:mm:ss");
    }

    public static String getJson(Object object,String dateFormate){
        ObjectMapper mapper = new ObjectMapper();
        //不使用时间戳
        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS,false);
        //自定义时间格式
        SimpleDateFormat sdf = new SimpleDateFormat(dateFormate);
        mapper.setDateFormat(sdf);
        try {
            return mapper.writeValueAsString(object);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }
}

Controller

package com.sw.controller;

import com.alibaba.fastjson.JSON;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.sw.pojo.User;
import com.sw.utils.JsonUtils;
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 java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * @Author suaxi
 * @Date 2020/12/17 15:38
 */

//@Controller
@RestController
public class UserController {

    @RequestMapping("/j1")
    //@ResponseBody //不会走视图解析器，直接返回一个字符串
    public String test01() throws JsonProcessingException {
        //jackson ObjectMapper
        ObjectMapper mapper = new ObjectMapper();
        User user = new User("孙笑川", 33, "男");
        String s = mapper.writeValueAsString(user);
        return s;
    }

    @RequestMapping("/j2")
    public String test02() throws JsonProcessingException {
        List<User> userList = new ArrayList<User>();
        User user1 = new User("孙笑川1", 33, "男");
        User user2 = new User("孙笑川2", 33, "男");
        User user3 = new User("孙笑川3", 33, "男");
        userList.add(user1);
        userList.add(user3);
        userList.add(user2);
        return JsonUtils.getJson(userList);
    }

    @RequestMapping("/j3")
    public String test03() throws JsonProcessingException {
        return JsonUtils.getJson(new Date());
    }
}

2、fastjson

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.75</version>
</dependency>

Controller

package com.sw.controller;

import com.alibaba.fastjson.JSON;
import com.sw.pojo.User;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

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

/**
 * @Author suaxi
 * @Date 2020/12/17 15:38
 */

//@Controller
@RestController
public class UserController {

    @RequestMapping("/j4")
    public String test04(){
        List<User> userList = new ArrayList<User>();
        User user1 = new User("孙笑川1", 33, "男");
        User user2 = new User("孙笑川2", 33, "男");
        User user3 = new User("孙笑川3", 33, "男");
        userList.add(user1);
        userList.add(user3);
        userList.add(user2);
        String s = JSON.toJSONString(userList);
        return s;
    }
}