httpurlconnection - 获取错误请求的主体 httpURLConnection.getInputStream()

Question

我一直在研究一个调用 Rest API 的 portlet。当API被调用且请求的数据不存在时，返回相应的JSON格式的错误信息(带有Bad request http code - 400)，如果id存在，则返回json格式的请求数据(带有代码200 )。
由于调用 httpConn.getInputStream()，如何获取响应正文(包含错误描述)如果响应是错误的请求错误，方法将引发异常。
代码:

HttpURLConnection httpConn = null;
URL url = new URL("http://192.168.1.20/personinfo.html?id=30");   
URLConnection connection = url.openConnection();
httpConn = (HttpURLConnection) connection;
httpConn.setRequestProperty("Accept", "application/json");
httpConn.setRequestMethod("GET");
httpConn.setRequestProperty("charset", "utf-8");
BufferedReader br = null;
if (!(httpConn.getResponseCode() == 400)) {
     br = new BufferedReader(new InputStreamReader((httpConn.getInputStream())));
     String output;
     StringBuilder builder = new StringBuilder();
     System.out.println("Output from Server .... \n");
     while ((output = br.readLine()) != null) 
          builder.append(output);
     return builder.toString();
}else
   here should catch the error message. :)

Answer 1

如果响应代码不成功，您必须使用 HttpURLConnection.getErrorStream() 阅读正文.