echotest.java

java网络编程的一个实例

//客户端程序
import java.io.*;
import java.net.*;
public class EchoTest {
public static void main(String[] args) {
Socket echoSocket = null;
DataOutputStream os = null;
DataInputStream is = null;
DataInputStream stdIn = new DataInputStream(System.in);
    try { 	echoSocket = new Socket("xyz-server", 4444);
    		os = new DataOutputStream(echoSocket.getOutputStream());
    	is = new DataInputStream(echoSocket.getInputStream());
     } catch (UnknownHostException e) {
     	System.err.println("Don't know about host: xyz-server");
     } catch (IOException e) {
     	System.err.println("Couldn't get I/O for the connection to: myHost");
     }
     if (echoSocket != null && os != null && is != null) {
     	try {
          	String userInput;
              while ((userInput = stdIn.readLine()) != null) {
              os.writeBytes(userInput);
              os.writeByte('\n');
              System.out.println("echo: " + is.readLine());	}
              os.close();
              is.close();
              echoSocket.close();
            } catch (IOException e) {
                System.err.println("I/O failed on the connection to: myHost");
            }
       }
    }
}