json解析之google开源工程gson的使用

json是在互联网上使用比较广、且比较轻量的一个数据格式。现在很多的开放平台都会用到这种格式做为返回的数据格式、比如新浪、腾讯的微博开放平台，都可以用这种数据格式来进行二次开发，Json使用很方便、我们可以写一个对应的类来解析这个数据。Google为了方便我们使用json开发了一个Gson包。我们只要导入这个包就可以很简单的解析和封装Json数据。

我们对中国天气Api返回的数据做一个简单的示例：

解析地址：http://www.weather.com.cn/data/cityinfo/101010100.html

json数据：{"weatherinfo":{"city":"北京","cityid":"101010100","temp1":"22℃","temp2":"9℃","weather":"晴","img1":"d0.gif","img2":"n0.gif","ptime":"11:00"}}

分析这个数据可以看出这个包含两个对象.外层一个属性

建立两个类Weather、Weatherinfo

package com.he.data;

public class Weather {
    private Weatherinfo weatherinfo;

    public Weatherinfo getWeatherinfo() {
        return weatherinfo;
    }

    public void setWeatherinfo(Weatherinfo weatherinfo) {
        this.weatherinfo = weatherinfo;
    }
    

}

package com.he.data;

public class Weatherinfo {
    private String city;
    private String cityid;
    private String temp1;
    private String temp2;
    private String weather;
    private String img1;
    private String img2;
    private String ptime;
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public String getCityid() {
        return cityid;
    }
    public void setCityid(String cityid) {
        this.cityid = cityid;
    }
    public String getTemp1() {
        return temp1;
    }
    public void setTemp1(String temp1) {
        this.temp1 = temp1;
    }
    public String getTemp2() {
        return temp2;
    }
    public void setTemp2(String temp2) {
        this.temp2 = temp2;
    }
    public String getWeather() {
        return weather;
    }
    public void setWeather(String weather) {
        this.weather = weather;
    }
    public String getImg1() {
        return img1;
    }
    public void setImg1(String img1) {
        this.img1 = img1;
    }
    public String getImg2() {
        return img2;
    }
    public void setImg2(String img2) {
        this.img2 = img2;
    }
    public String getPtime() {
        return ptime;
    }
    public void setPtime(String ptime) {
        this.ptime = ptime;
    }
    @Override
    public String toString() {
        return "Weatherinfo [city=" + city + ", cityid=" + cityid + ", temp1="
                + temp1 + ", temp2=" + temp2 + ", weather=" + weather
                + ", img1=" + img1 + ", img2=" + img2 + ", ptime=" + ptime
                + "]";
    }
    

    
}

完成这两个对应类就可以直接套用解析了：

package com.he;

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

import com.google.gson.Gson;
import com.he.data.Person;
import com.he.data.Weather;
import com.he.data.Weatherinfo;

public class testGson {
    
    public void gsonWeather(String str){
        Gson gson=new Gson();
        Weather weather=gson.fromJson(str, new Weather().getClass());//解析数据类
        System.out.println(weather.getWeatherinfo());
        System.out.println(gson.toJson(weather));//把对象变成json对象
    }
    
    public static void main(String[] args) {
        
        testGson test=new testGson();
        String str="{\"weatherinfo\":{\"city\":\"北京\",\"cityid\":\"101010100\",\"temp1\":\"22℃\",\"temp2\":\"9℃\",\"weather\":\"晴\",\"img1\":\"d0.gif\",\"img2\":\"n0.gif\",\"ptime\":\"11:00\"}}";
        test.gsonWeather(str);
        
    }

}

输出结果：

Weatherinfo [city=北京, cityid=101010100, temp1=22℃, temp2=9℃, weather=晴, img1=d0.gif, img2=n0.gif, ptime=11:00]
{"weatherinfo":{"city":"北京","cityid":"101010100","temp1":"22℃","temp2":"9℃","weather":"晴","img1":"d0.gif","img2":"n0.gif","ptime":"11:00"}}