使用HttpURLConnection在Request body中发送数据

我正在使用HttpURLConnection向使用JAVA Spark创建的本地部署的本地服务发出POST请求。 当我使用HttpURLConnection进行POST调用时，我想在请求体中发送一些数据，但每次JAVA Spark中的请求体都为null 。 以下是我正在使用的代码

Java Spark POST服务处理程序

post("/", (req, res) -> { System.out.println("Request Body: " + req.body()); return "Hello!!!!"; });

HTTPClass进行发布呼叫

 `public class HTTPClassExample{ public static void main(String[] args) { try{ URL url = new URL("http://localhost:4567/"); HttpURLConnection httpCon = (HttpURLConnection) url.openConnection(); httpCon.setDoOutput(true); httpCon.setRequestMethod("POST"); httpCon.connect(); OutputStream os = httpCon.getOutputStream(); OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8"); osw.write("Just Some Text"); System.out.println(httpCon.getResponseCode()); System.out.println(httpCon.getResponseMessage()); osw.flush(); osw.close(); }catch(Exception ex){ ex.printStackTrace(); } } }` 

Answer 1

你应该调用httpCon.connect(); 只有在您在身体中而不是之前编写参数之后。 您的代码应如下所示：

 URL url = new URL("http://localhost:4567/"); HttpURLConnection httpCon = (HttpURLConnection) url.openConnection(); httpCon.setDoOutput(true); httpCon.setRequestMethod("POST"); OutputStream os = httpCon.getOutputStream(); OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8"); osw.write("Just Some Text"); osw.flush(); osw.close(); os.close(); //don't forget to close the OutputStream httpCon.connect(); //read the inputstream and print it String result; BufferedInputStream bis = new BufferedInputStream(conn.getInputStream()); ByteArrayOutputStream buf = new ByteArrayOutputStream(); int result2 = bis.read(); while(result2 != -1) { buf.write((byte) result2); result2 = bis.read(); } result = buf.toString(); System.out.println(result); 

Answer 2

我发布了XML格式的请求数据，代码看起来像这样。 您还应该添加请求属性Accept和Content-Type。

 URL url = new URL("...."); HttpURLConnection httpConnection = (HttpURLConnection) url.openConnection(); httpConnection.setRequestMethod("POST"); httpConnection.setRequestProperty("Accept", "application/xml"); httpConnection.setRequestProperty("Content-Type", "application/xml"); httpConnection.setDoOutput(true); OutputStream outStream = httpConnection.getOutputStream(); OutputStreamWriter outStreamWriter = new OutputStreamWriter(outStream, "UTF-8"); outStreamWriter.write(requestedXml); outStreamWriter.flush(); outStreamWriter.close(); outStream.close(); System.out.println(httpConnection.getResponseCode()); System.out.println(httpConnection.getResponseMessage()); InputStream xml = httpConnection.getInputStream();