Java基础98 gson插件的使用

1、要用到的包  

概念：JSON是javascript对象的一种形态，是一种轻量级的数据交换格式。一般用来在Java EE后台服务和Android或者ios、HTML5之间进行通信的一种数据传递的格式。

　　   Gson是谷歌推出的一个用于生成和解析JSON数据格式的工具；

2、实例        

实体类 people

package com.shore.entity;

/**
 * @author DSHORE/2019-4-21
 *
 */
public class People {
    private int pid;
    private String pname;
    private int age;
    private String job;
    private double sal;
    
    public People() {
        
    }
    public People(int pid, String pname, int age, String job, double sal) {
        super();
        this.pid = pid;
        this.pname = pname;
        this.age = age;
        this.job = job;
        this.sal = sal;
    }
    public int getPid() {
        return pid;
    }
    public void setPid(int pid) {
        this.pid = pid;
    }
    public String getPname() {
        return pname;
    }
    public void setPname(String pname) {
        this.pname = pname;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getJob() {
        return job;
    }
    public void setJob(String job) {
        this.job = job;
    }
    public double getSal() {
        return sal;
    }
    public void setSal(double sal) {
        this.sal = sal;
    }
    @Override
    public String toString() {
        return "People [pid=" + pid + ", pname=" + pname + ", age=" + age
                + ", job=" + job + ", sal=" + sal + "]";
    }
}

gson 测试类

package com.shore.test;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

import net.sf.json.JSONObject;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.shore.entity.People;

/**
 * @author DSHORE/2019-4-21
 *
 */
public class GsonTest {
    public static void main(String[] args) {
        People p = new People();
        p.setAge(18);
        p.setPname("张三");
        p.setJob("工程师");
        p.setPid(1);
        p.setSal(10000);
        
        People p2 = new People();
        p2.setAge(20);
        p2.setPname("李四");
        p2.setJob("设计师");
        p2.setPid(2);
        p2.setSal(8000);
        
        People p3 = new People();
        p3.setAge(20);
        p3.setPname("王五");
        p3.setJob("工程师");
        p3.setPid(3);
        p3.setSal(15000);
        
        //1.将java对象转为json字符串
        Gson gson = new Gson();
        String json = gson.toJson(p);
        System.out.println(json); //返回值：{"pid":1,"pname":"张三","age":18,"job":"工程师","sal":10000.0}
        
        //2.将json字符串转为java对象
        json = "{"age":18,"job":"工程师","pid":1,"pname":"张三","sal":10000}";
        People people = gson.fromJson(json, People.class);
        System.out.println(people);//返回值：People [pid=1, pname=张三, age=18, job=工程师, sal=10000.0]
        //p2对象
        JSONObject jsonObject = JSONObject.fromObject(p2);
        System.out.println(jsonObject);//返回值：{"age":20,"job":"设计师","pid":2,"pname":"李四","sal":8000}
        
        //3.将一个对象集合转为json
        List<People> list = new ArrayList<People>();
        list.add(p);
        list.add(p2);
        list.add(p3);
        json=gson.toJson(list);
        System.out.println(json);//返回值：[{"pid":1,"pname":"张三","age":18,"job":"工程师","sal":10000.0},{"pid":2,"pname":"李四","age":20,"job":"设计师","sal":8000.0},{"pid":3,"pname":"王五","age":20,"job":"工程师","sal":15000.0}]
        
        //4.将json字符串转为带泛型集合对象
        Type listType=new TypeToken<List<People>>(){}.getType();
        List<People> list2=gson.fromJson(json,listType);
        System.out.println(list2.get(2).getPname());//返回值：王五          get(2)中的2表示：下标值
    }
}

json插件的使用（java对象和json字符串对象之间的转换）

原创作者：DSHORE

作者主页：http://www.cnblogs.com/dshore123/

原文出自：https://www.cnblogs.com/dshore123/p/10746722.html

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