Send HTTP POST request with Socket

Byron KiourtzoglouNovember 11th, 2012Last Updated: September 23rd, 2013

1 917 1 minute read

This is an example of how to send an HTTP POST request with a Socket. A socket is an endpoint for communication between two machines. Sending an HTTP POST request using a Socket implies that you should:

Get the InetAddress of a specified host, using the host’s name, with getByName(String host) API method of InetAddress.
Create a new Socket and connect it to a specified port number at a specified IP address.
Get the output stream of the socket, using getOutputStream() API method of Socket.
Create an OutputStreamWriter with the socket ouputstream that uses the given UTF-8 encoder.
Create a BufferedWriter that uses a default-sized output buffer.
Use write(String str) API method to send the headers and the parameters and flush() API method to flush the stream.
Get the socket input stream, using getInputStream() API method of Socket.
Create a new BufferedReader, using a new InputStreamReader with the socket input stream.
Use readLine() API method to read the response.
Don’t forget to close both the BufferedWriter and the BufferedReader using the close() API methods.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.URLEncoder;

public class SendHTTPPOSTRequestWithSocket {
	
	public static void main(String[] args) {
		
		try {
			
			String params = URLEncoder.encode("param1", "UTF-8")
+ "=" + URLEncoder.encode("value1", "UTF-8");
			params += "&" + URLEncoder.encode("param2", "UTF-8")
+ "=" + URLEncoder.encode("value2", "UTF-8");

			String hostname = "mysite.com";
			int port = 80;
			
			InetAddress addr = InetAddress.getByName(hostname);
			Socket socket = new Socket(addr, port);
			String path = "/myapp";

			// Send headers
			BufferedWriter wr =
     new BufferedWriter(new OutputStreamWriter(socket.getOutputStream(), "UTF8"));
			wr.write("POST "+path+" HTTP/1.0rn");
			wr.write("Content-Length: "+params.length()+"rn");
			wr.write("Content-Type: application/x-www-form-urlencodedrn");
			wr.write("rn");

			// Send parameters
			wr.write(params);
			wr.flush();

			// Get response
			BufferedReader rd = new BufferedReader(new InputStreamReader(socket.getInputStream()));
			String line;
			
			while ((line = rd.readLine()) != null) {
			    System.out.println(line);
			}
			
			wr.close();
			rd.close();
			
		}
		catch (Exception e) {
			e.printStackTrace();
		}
		
	}

}

This was an example of how to send an HTTP POST request using a Socket in Java.