1. 簡單的由服務端發送內容到客戶端：

Server:

package test;

import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
 
public class SocketServer {
 
    private static final int PORT = 8088;
 
    public static void main(String[] args) {
        ServerSocket server 
 
= null;
        try {
            server = new ServerSocket(PORT);
            while (true) {
                Socket client = server.accept();
                new Thread(new Server(client)).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    } 
}
 
 
class Server implements Runnable {
 
    private Socket client;
 
    public Server(Socket client) {
        this.client = client;
    }
 
    public void run() {
        DataOutputStream output = null;
        try {
            output = new DataOutputStream(client.getOutputStream());
            output.writeUTF(
 
"XXOOXXOOXXOO");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (output != null) output.close();
                output = null;
            } catch (IOException e) {}
        }
    }
 
}

client:

package test;

import java.io.*;
import java.net.Socket;
import java.net.UnknownHostException;
 
public class SSLClient extends Socket {
 
    private static final int PORT = 8088;
 
    public static void main(String[] args) {
        Socket socket = null;
        try {
            socket = new Socket("localhost", PORT);
            DataInputStream in = new DataInputStream(socket.getInputStream());
            String res = in.readUTF();
            System.out.println(res);
            if (in != null) in.close();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException e) {}
            }
        }
    }
}

2. server 和 client 溝通通訊：

server:

package test;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
 
public class SocketServer {
 
    private static final int PORT = 8088;
 
    public static void main(String[] args) {
//        ServerSocket server = null;
        try {
            ServerSocket server = new ServerSocket(PORT);            
            Socket socket = server.accept();
//            new Thread(new Server(socket)).start();

            InputStream msg = socket.getInputStream();
            InputStreamReader read = new InputStreamReader(msg);
            BufferedReader br = new BufferedReader(read);
            String info = null;
            
            while ((info = br.readLine())!= null) {
                System.out.println("I am server, the client says: " + info);
            }
            socket.shutdownInput();
            OutputStream os = socket.getOutputStream();
            PrintWriter pw = new PrintWriter(os);
            pw.write("Welcome!");
            pw.flush();
            pw.close();
            os.close();
            br.close();
            read.close();
            msg.close();
            socket.close();            
            
        } catch (IOException e) {
            e.printStackTrace();
        }
    } 
}

client:

package test;

import java.io.*;
import java.net.Socket;
import java.net.UnknownHostException;
 
public class SSLClient extends Socket {
 
    private static final int PORT = 8088;
 
    public static void main(String[] args) {
        Socket socket = null;
        try {
            socket = new Socket("localhost", PORT);
            
            OutputStream os = socket.getOutputStream();
            PrintWriter pw = new PrintWriter(os);
            
            pw.write("user: admin; passwd: 123");
            pw.flush();
            socket.shutdownOutput();
            InputStream is = socket.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String info = null;
            
            while((info=br.readLine()) != null){
                System.out.println("I am client, server says: " + info);
            }
            
            br.close();
            is.close();
            pw.close();
            os.close();
            socket.close();
            
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException e) {}
            }
        }
    }
}

Java Socket 網絡編程