fastjson是阿里巴巴的开源JSON解析库，它可以解析JSON格式的字符串，支持将Java Bean序列化为JSON字符串，也可以从JSON字符串反序列化到JavaBean。 fastjson是json的序列化和反序列化

一、添加依赖

<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.83</version>
</dependency>

完整的pom文件如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.7.15</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.example</groupId><artifactId>FastJsonDemo</artifactId><version>0.0.1-SNAPSHOT</version><name>FastJsonDemo</name><description>FastJsonDemo</description><properties><java.version>1.8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.83</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.28</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>2.7.15</version></plugin></plugins></build></project>

二、创建实体

package com.example.fastjsondemo.model;import lombok.Data;/*** @author qx* @date 2023/8/29* @des*/
@Data
public class Student {private Long id;private String name;private Integer age;}

package com.example.fastjsondemo.model;import lombok.Data;/*** @author qx* @date 2023/8/29* @des*/
@Data
public class School {private String name;private String address;
}

三、测试

将对象生成json

  /*** 将一个对象转成Json*/@Testvoid testToJson() {Student student = new Student();student.setId(1L);student.setName("qx");student.setAge(20);String json = JSONObject.toJSONString(student);// 输出{"age":20,"id":1,"name":"qx"}System.out.println(json);}

json转对象

    /*** json转对象*/@Testvoid testToObject() {String data = "{\"age\":20,\"id\":1,\"name\":\"qx\"}";Student student = JSONObject.parseObject(data, Student.class);// 输出Student(id=1, name=qx, age=20)System.out.println(student);}

根据键获取Json数据中的值

   /*** 获取json中的值*/@Testvoid testAccessValue() {String data = "{\"age\":20,\"id\":1,\"name\":\"qx\"}";JSONObject jsonObject = JSONObject.parseObject(data);String name = jsonObject.getString("name");// 输出qxSystem.out.println(name);int age = jsonObject.getIntValue("age");// 输出20System.out.println(age);}

四、实体类中存在其他对象的情况

package com.example.fastjsondemo.model;import lombok.Data;/*** @author qx* @date 2023/8/29* @des*/
@Data
public class Student {private Long id;private String name;private Integer age;private School school;}

测试

对象转Json

 @Testvoid testToJson() {Student student = new Student();student.setId(1L);student.setName("qx");student.setAge(20);School school = new School();school.setName("广西大学");school.setAddress("南宁西乡塘区");student.setSchool(school);String json = JSONObject.toJSONString(student);// 输出{"age":20,"id":1,"name":"qx","school":{"address":"南宁西乡塘区","name":"广西大学"}}System.out.println(json);}

Json转对象

  /*** json转对象*/@Testvoid testToObject() {String data = "{\"age\":20,\"id\":1,\"name\":\"qx\",\"school\":{\"address\":\"南宁西乡塘区\",\"name\":\"广西大学\"}}";Student student = JSONObject.parseObject(data, Student.class);// 输出Student(id=1, name=qx, age=20, school=School(name=广西大学, address=南宁西乡塘区))System.out.println(student);}

获取Json中的某个值

    /*** 获取json中的值*/@Testvoid testAccessValue() {String data = "{\"age\":20,\"id\":1,\"name\":\"qx\",\"school\":{\"address\":\"南宁西乡塘区\",\"name\":\"广西大学\"}}";JSONObject jsonObject = JSONObject.parseObject(data);JSONObject school = jsonObject.getJSONObject("school");String name = school.getString("name");// 输出 广西大学System.out.println(name);}