Question

I have a code to send request to php page and it worked fine, but suddenly(I don’t remember changing anything) it stopped working both on emulator and on real device

    URL url = new URL(this.site); 
            URLConnection conn = url.openConnection();

            if (!(conn instanceof HttpURLConnection))    { 
                Log.e(TAG, "connection is not HttpURLConnection");  
                throw new IOException("Not an HTTP connection");

            }

            try{
                Log.e(TAG, "Trying");
                HttpURLConnection httpConn = (HttpURLConnection) conn;
                Log.e(TAG, "Created connection");
                httpConn.setAllowUserInteraction(false);
                httpConn.setInstanceFollowRedirects(true);
                httpConn.setRequestMethod("POST");
                Log.e(TAG, "connecting");
                httpConn.connect(); 
                Log.e(TAG, "connected");

                OutputStreamWriter wr = new OutputStreamWriter(httpConn.getOutputStream());
                Log.e(TAG, "created outputstream");

Here is the stacktrace:

     12-25 00:32:14.024: W/System.err(885): java.net.ProtocolException: Does not support output
     12-25 00:32:14.090: W/System.err(885):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:575)
     12-25 00:32:14.090: W/System.err(885):     at com.*****.StringAsyncRetriever.OpenHttpConnection(StringAsyncRetriever.java:122)
     12-25 00:32:14.090: W/System.err(885):     at com.******.StringAsyncRetriever.getData(StringAsyncRetriever.java:66)
     12-25 00:32:14.094: W/System.err(885):     at com.******.StringAsyncRetriever.doInBackground(StringAsyncRetriever.java:38)
     12-25 00:32:14.094: W/System.err(885):     at com.******.StringAsyncRetriever.doInBackground(StringAsyncRetriever.java:1)
     12-25 00:32:14.094: W/System.err(885):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
     12-25 00:32:14.094: W/System.err(885):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
     12-25 00:32:14.094: W/System.err(885):     at java.util.concurrent.FutureTask.run(FutureTask.java:138)
     12-25 00:32:14.094: W/System.err(885):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
     12-25 00:32:14.094: W/System.err(885):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
     12-25 00:32:14.094: W/System.err(885):     at java.lang.Thread.run(Thread.java:1019)

Answer 1

Looking at the source code, that exception is thrown when doOutput is not set to true:

(From: http://www.java2s.com/Open-Source/Android/android-core/platform-libcore/org/apache/harmony/luni/internal/net/www/protocol/http/HttpURLConnectionImpl.java.htm)

public OutputStream getOutputStream() throws IOException {
    if (!doOutput) {
        throw new ProtocolException("Does not support output");
    }

The HttpURLConnectionImpl class is extended from Java’s HttpUrlConnection class which extends URLConnection. Looking at the javadocs for that you find:

protected boolean doOutput

This variable is set by the setDoOutput
method. Its value is returned by the getDoOutput method. A URL
connection can be used for input and/or output. Setting the doOutput
flag to true indicates that the application intends to write data to
the URL connection.

The default value of this field is false.

So, you need to do:

httpConn.setDoOutput(true);

in your code.