java实现网络监听

import java.net.*;
import java.io.*;

public class tcpServer {

public static void main(String args[]) {

int port;
ServerSocket server_socket;
BufferedReader input;
try {
port = Integer.parseInt(args[0]);
}
catch (Exception e) {
System.out.println("port = 1500 (default)");
port = 1500;
}

try {
server_socket = new ServerSocket(port);
System.out.println("Server waiting for client on port " +
server_socket.getLocalPort());
// server infinite loop
while(true) {
Socket socket = server_socket.accept();
System.out.println("New connection accepted " +
socket.getInetAddress() +
":" + socket.getPort());
input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
// print received data
try {
while(true) {
String message = input.readLine();
if (message==null) break;
System.out.println(message);
}
}
catch (IOException e) {
System.out.println(e);
}

// connection closed by client
try {
socket.close();
System.out.println("Connection closed by client");
}
catch (IOException e) {
System.out.println(e);
}
}
}
catch (IOException e) {
System.out.println(e);
}
}
}

import java.net.*;
import java.io.*;

public class tcpClient {

public static void main(String[] args) {

int port = 1500;
String server = "localhost";
Socket socket = null;
String lineToBeSent;
BufferedReader input;
PrintWriter output;
int ERROR = 1;

// read arguments
if(args.length == 2) {
server = args[0];
try {
port = Integer.parseInt(args[1]);
}
catch (Exception e) {
System.out.println("server port = 1000 (default)");
port = 1500;
}
}

// connect to server
try {
socket = new Socket(server, port);
System.out.println("Connected with server " +
socket.getInetAddress() +
":" + socket.getPort());
}
catch (UnknownHostException e) {
System.out.println(e);
System.exit(ERROR);
}
catch (IOException e) {
System.out.println(e);
System.exit(ERROR);
}

try {
input = new BufferedReader(new InputStreamReader(System.in));
output = new PrintWriter(socket.getOutputStream(),true);

// get user input and transmit it to server
while(true) {
lineToBeSent = input.readLine();
// stop if input line is "."
if(lineToBeSent.equals(".")) break;
output.println(lineToBeSent);
}
}
catch (IOException e) {
System.out.println(e);
}

try {
socket.close();
}
catch (IOException e) {
System.out.println(e);
}
}
}