java发起http请求获取返回的Json对象方法

话不多说，先看代码！

/**
* 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"));
}
}

看第一个方法，发送get请求获取后台数据，其中，将返回回来的字符串解析成json对象用到了google的Gson.jar包，用到了其中JsonParser的parse方法。

第二个方法，发送post数据到后台并获取后台数据。

来源：https://blog.csdn.net/jeanFlower/article/details/74494136