Java中fastjson2包使用总结

 Java Json常用方法

fastjson2介绍

• 支持JSON/JSONB两种协议，JSONPath 是一等公民。
• 支持全量解析和部分解析。
• 支持Java服务端、客户端Android、大数据场景。
• 支持Kotlin
• 支持JSON Schema https://alibaba.github.io/fastjson2/json_schema_cn
• 支持Android (2.0.19.android)
• 支持Graal Native-Image (2.0.19.graal)

fastjson2下载

fastjson2 包下载地址：https://repo1.maven.org/maven2/com/alibaba/fastjson2/fastjson2/2.0.19/fastjson2-2.0.19.jar

fastjson2安装

将刚才下载的jar文件导入我们的项目

2.maven导入fastjson2

<!-- https://mvnrepository.com/artifact/com.alibaba.fastjson2/fastjson2 -->
<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2</artifactId>
    <version>2.0.19</version>
</dependency>

Java类转换为json字符串

import com.alibaba.fastjson2.JSON;

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

/**
 *Java对象转json字符串
 */
public class StringToJSON {
    public static void main(String[] args) {
        //定义JSON字符串
        Employee e = new Employee("易学教程","male", 22);
        System.out.println(JSON.toJSONString(e));
        Employee e2 = new Employee("易学教程2","male", 23);
        Employee e3 = new Employee("易学教程3","male", 25);
        List<Employee> list = new ArrayList<>();
        list.add(e);
        list.add(e2);
        list.add(e3);
        System.out.println(JSON.toJSONString(list));

    }
}

//JavaBean.java
class  Employee{

    private String name;
    private String sex;
    private Integer age;

    @Override
    public String toString() {
        return "Employee{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                '}';
    }

    public Employee(String name, String sex, Integer age) {
        this.name = name;
        this.sex = sex;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

测试一下

输出

 Json字符串转Java对象

 import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONObject;
import com.alibaba.fastjson2.TypeReference;

import java.util.List;

/**
 *解析Json字符串反序列化为Java对象
 */
public class StringToJSON {
    public static void main(String[] args) {
        //定义JSON字符串
        String jsonStr = "{\"age\":22,\"name\":\"易学教程\",\"sex\":\"male\"}";
        Employee e = (Employee) JSON.parseObject(jsonStr, Employee.class);//简单java类解析
        System.out.println("json字符串转简单java对象:"+e.toString());
        //解析带有list的json字符串
        String jsonStr2 = "[{\"age\":22,\"name\":\"易学教程\",\"sex\":\"male\"},{\"age\":23,\"name\":\"易学教程2\",\"sex\":\"male\"},{\"age\":25,\"name\":\"易学教程3\",\"sex\":\"male\"}]";
        List<Employee> list =
        JSONObject.parseObject(jsonStr2, new TypeReference<List<Employee>>(){});
        System.out.println(list);

    }
}

//JavaBean.java
class  Employee{

    private String name;
    private String sex;
    private Integer age;

    @Override
    public String toString() {
        return "Employee{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                '}';
    }
    public Employee() {
    }
    public Employee(String name, String sex, Integer age) {
        this.name = name;
        this.sex = sex;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}