Spring MVC学习05JSON序列化

修改pom文件，添加jackson的依赖：

<!-- Spring MVC默认使用jackson作为JSON处理方式 -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.8</version>
</dependency>

修改User类，添加一些Jackson的注解：

package com.yas.entity;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.yas.serialize.MySerializer;

import java.util.Date;

public class User {
    //json序列化时的名称
    @JsonProperty("id2")
    private Integer id;

    //如果为空，则不转化
    @JsonInclude(JsonInclude.Include.NON_NULL)
    private String name;

    //忽略此属性
    @JsonIgnore
    private Boolean gender;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")
    private Date birth;

    //自定义格式化
    @JsonSerialize(using = MySerializer.class)
    private Double salary = 10000.126;


    public User() {
    }

    public User(Integer id, String name, Boolean gender, Date birth) {
        this.id = id;
        this.name = name;
        this.gender = gender;
        this.birth = birth;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Boolean getGender() {
        return gender;
    }

    public void setGender(Boolean gender) {
        this.gender = gender;
    }

    public Date getBirth() {
        return birth;
    }

    public void setBirth(Date birth) {
        this.birth = birth;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", gender=" + gender +
                ", birth=" + birth +
                '}';
    }
}

添加用于自定义格式化的类：

package com.yas.serialize;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

import java.io.IOException;
import java.math.BigDecimal;

public class MySerializer extends JsonSerializer<Double> {

    @Override
    public void serialize(Double aDouble, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
        String number = BigDecimal.valueOf(aDouble).setScale(2,BigDecimal.ROUND_HALF_UP).toString();
        jsonGenerator.writeNumber(number);
    }
}

添加测试用的Controller：

package com.yas.controller;

import com.yas.entity.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

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

@Controller
@RequestMapping("/json")
public class JsonController {

    @ResponseBody
    @RequestMapping("/test1")
    public User test1(){
        User user = new User(1,"zhangsan",true,new Date());
        return user;
    }

    @ResponseBody
    @RequestMapping("/test2")
    public List<User> test2(){
        User user1 = new User(1,"zhangsan",true,new Date());
        User user2 = new User(2,"lisi",true,new Date());
        List<User> users = new ArrayList<User>();
        users.add(user1);
        users.add(user2);
        return users;
    }

    @ResponseBody
    @RequestMapping(value = "/test3",produces = "text/html;charset=utf-8")
    public String test3(){
        return "你好aaa";
    }

    @ResponseBody
    @RequestMapping("/test4")
    public String test4(@RequestBody User user){
        //@RequestBody 从json字符串封装到User对象中，只支持post提交
        System.out.println(user.getId());
        System.out.println(user.getName());
        return "ok";
    }
}

添加jsp页面

<%--
  Created by IntelliJ IDEA.
  User: yanga
  Date: 2021/10/26
  Time: 15:19
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
  <title>Title</title>
  <script src="https://code.jquery.com/jquery-2.1.0.min.js"></script>
  <script type="text/javascript">
    $(function (){
      $("#btn").click(function (){
        let user = {id:1,name:"张三"};
        let userJson = JSON.stringify(user);
        $.ajax({
          url:"${pageContext.request.contextPath}/json/test4",
          type:"post",
          data:userJson,
          contentType:"application/json",
          success:function (d){
            console.log(d);
          }
        });
      });
    });

  </script>
</head>
<body>
  <input type="button" value="发送json" id="btn" />
</body>
</html>