Java - Socket shutdownOutput() Method

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Description

The Java Socket shutdownOutput() disables the output stream for this socket. For a TCP socket, any previously written data will be sent followed by TCP's normal connection termination sequence. If you write to a socket output stream after invoking shutdownOutput() on the socket, the stream will throw an IOException.

Declaration

Following is the declaration for java.net.Socket.shutdownOutput() method.

public void shutdownOutput() throws IOException

Parameters

NA

Return Value

NA

Exception

IOException − if an I/O error occurs when shutting down this socket.

Example

The following example shows the usage of Java Socket shutdownOutput() method to disable the output stream for this socket. As first step, we've created a GreetingClient class where we're reading the servername and port using command line argument. A Socket instance is created as client using servername and port provided. Using client.getInputStream(), we're reading the content sent by the server. InputStream instance is then cast to DataInputStream and then printed using DataInputStream.readUTF() method. As we've invoked shutdownOutput() before writeUTF() method call, this code raises an exception as shown in the output of the program.

The following GreetingClient program is an example of a client application that uses the Socket class to listen for server output on a port number specified by a command-line argument −

package com.tutorialspoint;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class GreetingClient {

   public static void main(String [] args) {
      String serverName = args[0];
      int port = Integer.parseInt(args[1]);
      try {
         System.out.println("Connecting to " + serverName + " on port " + port);
         Socket client = new Socket(serverName, port);
         
         System.out.println("Just connected to " + client.getRemoteSocketAddress());
         OutputStream outToServer = client.getOutputStream();
         DataOutputStream out = new DataOutputStream(outToServer);
         
         out.writeUTF("Hello from " + client.getLocalSocketAddress());
         InputStream inFromServer = client.getInputStream();
         DataInputStream in = new DataInputStream(inFromServer);
         
         System.out.println("Server says " + in.readUTF());
         client.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

The following GreetingServer program is an example of a server application that uses the Socket class to listen for clients on a port number specified by a command-line argument −

package com.tutorialspoint;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketTimeoutException;

public class GreetingServer extends Thread {
   private ServerSocket serverSocket;
   
   public GreetingServer(int port) throws IOException {
      serverSocket = new ServerSocket(port);
      serverSocket.setSoTimeout(10000);
   }

   public void run() {
      while(true) {
         try {
            System.out.println("Waiting for client on port " + 
               serverSocket.getLocalPort() + "...");
            Socket server = serverSocket.accept();
            
            System.out.println("Just connected to " + server.getRemoteSocketAddress());
            DataInputStream in = new DataInputStream(server.getInputStream());
            
            System.out.println(in.readUTF());
            DataOutputStream out = new DataOutputStream(server.getOutputStream());
            server.shutdownOutput();
            out.writeUTF("Thank you for connecting to " + server.getLocalSocketAddress()
               + "\nGoodbye!");
            server.close();
            
         } catch (SocketTimeoutException s) {
            System.out.println("Socket timed out!");
            break;
         } catch (IOException e) {
            e.printStackTrace();
            break;
         }
      }
   }
   
   public static void main(String [] args) {
      int port = Integer.parseInt(args[0]);
      try {
         Thread t = new GreetingServer(port);
         t.start();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

Compile the client and the server and then start the server as follows −

Waiting for client on port 6066...
Just connected to /127.0.0.1:60982
Hello from /127.0.0.1:60982
java.net.SocketException: Cannot send after socket shutdown: socket write error
	at java.base/java.net.SocketOutputStream.socketWrite0(Native Method)
	at java.base/java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:110)
	at java.base/java.net.SocketOutputStream.write(SocketOutputStream.java:150)
	at java.base/java.io.DataOutputStream.write(DataOutputStream.java:107)
	at java.base/java.io.DataOutputStream.writeUTF(DataOutputStream.java:401)
	at java.base/java.io.DataOutputStream.writeUTF(DataOutputStream.java:323)
	at com.tutorialspoint.GreetingServer.run(GreetingServer.java:31)

Check the client program as follows −

Output

Connecting to localhost on port 6066
Just connected to localhost/127.0.0.1:6066
java.io.EOFException
	at java.base/java.io.DataInputStream.readUnsignedShort(DataInputStream.java:345)
	at java.base/java.io.DataInputStream.readUTF(DataInputStream.java:594)
	at java.base/java.io.DataInputStream.readUTF(DataInputStream.java:569)
	at com.tutorialspoint.GreetingClient.main(GreetingClient.java:28)
	at com.tutorialspoint.GreetingClient.main(GreetingClient.java:28)

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