HttpURLConnection POST, conn.getOutputStream() throwing Exception

Question

I want to make a POST by using HttpURLConnection. I am trying this in 2 ways, but I always get an excetion when doing: conn.getOutputStream();

The excep

Answer 1

The URL simply cannot be reached. Either the URL is wrong, or the DNS server couldn't resolve the hostname. Try a simple connect with a well-known URL to exclude one and other, e.g.

InputStream response = new URL("http://stackoverflow.com").openStream();
// Consume response.

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Update as per the comments, you're required to use a proxy server for HTTP connections. You need to configure that in the Java side as well. Add the following lines before any attempt to connect to an URL.

System.setProperty("http.proxyHost", "proxy.example.com");
System.setProperty("http.proxyPort", "8080");

It suffices to do this only once during runtime.

See also:

• Java guides - Networking and proxies

Answer 2

Without establishing the connection (which in this case requires 1 more step to be performed ie connect), transfer is not possible. connect() should be called after the connection is configured (ie after being done with the set***() on the connection).

What is missing is:

conn.connect();