gson的使用

　　Android中有的时候通过第三方API接口获取json格式的数据，那么如何解析json格式的数据呢？

其实我们可以使用gson.jar来帮我们完成这项工作。

比如一个json的格式如下：

{"xingming":"wyl","sex":"male","hobby":"zhihu"}，

如果我们用gson来帮我们解析，那么我们就需要编写一个javabean,而这个bean的属性就是json的属性。

具体实例如下：

package wyl;

import java.util.ArrayList;
/**
 * 用于gson解析
 * @author Administrator
 *
 */
public class ReturnMsg {
	String code;
	String text;
	public static ArrayList list;
	public String getCode() {
		return code;
	}
	public void setCode(String code) {
		this.code = code;
	}
	public String getText() {
		return text;
	}
	public void setText(String text) {
		this.text = text;
	}
	public static ArrayList getList() {
		return list;
	}
	public static void setList(ArrayList list) {
		ReturnMsg.list = list;
	}
	
}

　　测试类：

package wyl;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;

import com.google.gson.Gson;

public class gsonTest {
	public static void main(String[] args) throws IOException {
		String key = "e59219b3f450256c2a3da7157ae651f2";
		String info = "上海到成都的火车";//问题
//		String info = "我爱你";//问题
		info = URLEncoder.encode(info, "UTF-8");
		String url = "http://www.tuling123.com/openapi/api?key="+key+"&info="+info;
		
		URL u = new URL(url);
		URLConnection conn = u.openConnection();
		conn.connect();
		InputStream ips = conn.getInputStream();
		
		BufferedReader reader = new BufferedReader(new InputStreamReader( ips, "utf-8"));
        StringBuffer sb = new StringBuffer();
        String line = "";
        while ((line = reader.readLine()) != null) {
            sb.append(line);
        }
        reader.close();
        System.out.println("sb："+sb);
        String sb2 = sb.toString();
        Gson gson = new Gson();//实例化一个gson对象
        //gson.fromJson(paraA,paraB);把json对象转化为java对象，
        //paraA是String类型的json字符串，paraB是这个json对应Bean的类类型(java反射中有)
        ReturnMsg rtn = gson.fromJson(sb2, ReturnMsg.class);//sb：{"code":305000,"text":"亲，已帮您找到列车信息","list":[{"trainnum":"D636/D637(动车组)","start":"上海虹桥","terminal":"成都东","starttime":"06:09","endtime":"21:15","icon":"http://unidust.cn/images/api-train.jpg","detailurl":"http://touch.qunar.com/h5/train/"},{"trainnum":"D2206/D2207(动车组)","start":"上海虹桥","terminal":"成都东","starttime":"06:39","endtime":"21:47","icon":"http://unidust.cn/images/api-train.jpg","detailurl":"http://touch.qunar.com/h5/train/"},{"trainnum":"K290/K291(快速)","start":"上海","terminal":"成都","starttime":"08:43","endtime":"21:33(+1)","icon":"http://unidust.cn/images/api-train.jpg","detailurl":"http://touch.qunar.com/h5/train/"},{"trainnum":"K1156/K1157(快速)","start":"上海","terminal":"成都","starttime":"09:16","endtime":"16:18(+1)","icon":"http://unidust.cn/images/api-train.jpg","detailurl":"http://touch.qunar.com/h5/train/"},{"trainnum":"K351/K354(快速)","start":"上海南","terminal":"成都","starttime":"17:34","endtime":"04:07(+2)","icon":"http://unidust.cn/images/api-train.jpg","detailurl":"http://touch.qunar.com/h5/train/"},{"trainnum":"K282/K283(快速)","start":"上海","terminal":"成都","starttime":"20:40","endtime":"11:30(+2)","icon":"http://unidust.cn/images/api-train.jpg","detailurl":"http://touch.qunar.com/h5/train/"}]}

        System.out.println("code:"+rtn.getCode());//code:305000
        System.out.println("text:"+rtn.getText());//text:亲，已帮您找到列车信息
	}
}