java后台代码打开一个链接，并获取json数据

String url = "";

URL shixun = new URL(url );

InputStream in =  shixun .openStream();

//utils转换成String

String ret = StringUitles.toString(in,"utf-8");

JsonObject json = JsonObejct.fromObject(ret);

//然后在去解析json就行了.....