java发起http请求获取返回的Json对象方法

/** * Created by david on 2017-7-5. */import com.google.gson.JsonObject;import com.google.gson.JsonParser;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;public class HttpRequestUtil { /**  * 发起http请求并获取结果  * @param requestUrl 请求地址  */ public static JsonObject getXpath(String requestUrl){  String res="";  JsonObject object = null;  StringBuffer buffer = new StringBuffer();  try{   URL url = new URL(requestUrl);   HttpURLConnection urlCon= (HttpURLConnection)url.openConnection();   if(200==urlCon.getResponseCode()){    InputStream is = urlCon.getInputStream();    InputStreamReader isr = new InputStreamReader(is,"utf-8");    BufferedReader br = new BufferedReader(isr);    String str = null;    while((str = br.readLine())!=null){     buffer.append(str);    }    br.close();    isr.close();    is.close();    res = buffer.toString();    JsonParser parse =new JsonParser();    object = (JsonObject) parse.parse(res);   }  }catch(IOException e){   e.printStackTrace();  }  return object; } public static JsonObject postDownloadJson(String path,String post){  URL url = null;  try {   url = new URL(path);   HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();   httpURLConnection.setRequestMethod("POST");// 提交模式   // conn.setConnectTimeout(10000);//连接超时 单位毫秒   // conn.setReadTimeout(2000);//读取超时 单位毫秒   // 发送POST请求必须设置如下两行   httpURLConnection.setDoOutput(true);   httpURLConnection.setDoInput(true);   // 获取URLConnection对象对应的输出流   PrintWriter printWriter = new PrintWriter(httpURLConnection.getOutputStream());   // 发送请求参数   printWriter.write(post);//post的参数 xx=xx&yy=yy   // flush输出流的缓冲   printWriter.flush();   //开始获取数据   BufferedInputStream bis = new   BufferedInputStream(httpURLConnection.getInputStream());   ByteArrayOutputStream bos = new ByteArrayOutputStream();   int len;   byte[] arr = new byte[1024];   while((len=bis.read(arr))!= -1){    bos.write(arr,0,len);    bos.flush();   }   bos.close();   JsonParser parse = new JsonParser();   return (JsonObject)parse.parse(bos.toString("utf-8"));  } catch (Exception e) {   e.printStackTrace();  }  return null; } //测试 public static void main(String args [] ) {  JsonObject res = null; //  res = getXpath("http://ip.taobao.com/service/getIpInfo.php?ip=63.223.108.42");  res = postDownloadJson("http://ip.taobao.com/service/getIpInfo.php?ip=63.223.108.42","123");  System.out.println(res);  System.out.println(res.get("code"));  System.out.println(res.get("data")); }}