AppEngine : howto see content from a POST request

I send a POST request to my AppEngine server. The HttpServletRequest says me :

POST /connexionDeconnexio开发者_如何学运维n HTTP/1.1
User-Agent: Java/1.6.0_20
Host: localhost:8888
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 25

I have sent the world "HelloHelloHelloHelloHello", which is correct according to the Content-Length. However, I don't know how to recover it. Can you explain me ?

As Jigar said you can use request.getParameter(). This works if you really submit the form or specify parameter as a URL argument (http://myhost/mypath?myparam=myvalue).

If you send your data as a POST body you should read it from its body, i.e. retrieve input stream by calling request.getInputStream() and then read from this stream.

You shoudl give param name and value and then you can extract param from httpRequest object.

request.getParameter("paramName");

Update

client side

String param = "value";
File textFile = new File("/path/to/file.txt");
File binaryFile = new File("/path/to/file.bin");
String boundary = Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value.

URLConnection connection = new URL(url).openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
PrintWriter writer = null;
try {
    OutputStream output = connection.getOutputStream();
    writer = new PrintWriter(new OutputStreamWriter(output, charset), true); // true = autoFlush, important!

    // Send normal param.
    writer.println("--" + boundary);
    writer.println("Content-Disposition: form-data; name=\"param\"");
    writer.println("Content-Type: text/plain; charset=" + charset);
    writer.println();
    writer.println(param);

    // Send text file.
    writer.println("--" + boundary);
    writer.println("Content-Disposition: form-data; name=\"textFile\"; filename=\"" + textFile.getName() + "\"");
    writer.println("Content-Type: text/plain; charset=" + charset);
    writer.println();
    BufferedReader reader = null;
    try {
        reader = new BufferedReader(new InputStreamReader(new FileInputStream(textFile), charset));
        for (String line; (line = reader.readLine()) != null;) {
            writer.println(line);
        }
    } finally {
        if (reader != null) try { reader.close(); } catch (IOException logOrIgnore) {}
    }

    // Send binary file.
    writer.println("--" + boundary);
    writer.println("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"" + binaryFile.getName() + "\"");
    writer.println("Content-Type: " + URLConnection.guessContentTypeFromName(binaryFile.getName());
    writer.println("Content-Transfer-Encoding: binary");
    writer.println();
    InputStream input = null;
    try {
        input = new FileInputStream(binaryFile);
        byte[] buffer = new byte[1024];
        for (int length = 0; (length = input.read(buffer)) > 0;) {
            output.write(buffer, 0, length);
        }
        output.flush(); // Important! Output cannot be closed. Close of writer will close output as well.
    } finally {
        if (input != null) try { input.close(); } catch (IOException logOrIgnore) {}
    }
    writer.println(); // Important! Indicates end of binary boundary.

    // End of multipart/form-data.
    writer.println("--" + boundary + "--");
} finally {
    if (writer != null) writer.close();
}

Also See

• how-to-use-java-net-urlconnection-to-fire-and-handle-http-requests