import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;public class ChatServer{private ServerSocket ss = null;private boolean started = false;public static void main(String[] args) {new ChatServer().start();}public void start(){try {ss = new ServerSocket(8888);started = true;} catch (IOException e1) {e1.printStackTrace();}try {while(started){//!!!!!注意accept()是阻塞性方法，当被readUTF()阻塞时它不会被执行Socket s = ss.accept();
System.out.println("a client connect------"+s);new Thread(new Client(s)).start();}} catch (EOFException e) {System.out.println("客户端已关闭！");} catch (IOException e) {e.printStackTrace();}finally{try {//if(dis != null ) dis.close();//if(s != null ) s.close();if(ss != null ) ss.close();} catch (Exception e) {e.printStackTrace();}}}private class Client implements Runnable{private Socket s;private DataInputStream dis = null;boolean bConnect = false;public Client(Socket s) {super();this.s = s;try {dis = new DataInputStream(s.getInputStream());bConnect = true;} catch (IOException e) {e.printStackTrace();}}@Overridepublic void run() {try {while(bConnect){//!!!!!注意readUTF()是阻塞性方法System.out.println(dis.readUTF());}} catch (EOFException e) {System.out.println("客户端已关闭！");} catch (IOException e) {e.printStackTrace();}finally{try {if(dis != null ) dis.close();if(s != null ) s.close();} catch (Exception e) {e.printStackTrace();}}}}}

import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;public class ChatClient extends Frame{private TextField tfText;private TextArea taContent;
//  private Button btnSend;private Socket socket;private DataOutputStream dos;public void launchFrame(){addWindowListener(new WindowAdapter() {public void windowClosing(WindowEvent e) {disconnect();System.exit(0);}});tfText = new TextField();taContent = new TextArea();
//      btnSend = new Button("发送");
//
//      btnSend.addActionListener(new ActionListener() {
//          @Override
//          public void actionPerformed(ActionEvent e) {
//              //taContent.setText(taContent.getText()+"\n\r"+tfText.getText());
//              //tfText.setText("");
//              try {
//                  DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
//                  dos.writeUTF(tfText.getText());
//                  dos.close();
//                  socket.close();
//              } catch (IOException e1) {
//                  e1.printStackTrace();
//              }
//          }
//      });tfText.addActionListener(new TFListener());add(taContent,BorderLayout.NORTH);add(tfText,BorderLayout.CENTER);
//      add(btnSend,BorderLayout.SOUTH);setLocation(300, 100);pack();setVisible(true);connect("localhost", 8888);}//当调用了此方法，会自动把成员变量给socket连接上serverpublic void  connect(String address, int port){try {socket = new Socket(address, port);dos = new DataOutputStream(socket.getOutputStream());} catch (UnknownHostException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}//退出时释放资源public void disconnect(){try {if(dos != null ) dos.close();if(socket != null ) socket.close();} catch (IOException e) {e.printStackTrace();}}class TFListener implements ActionListener{@Overridepublic void actionPerformed(ActionEvent e) {taContent.setText(taContent.getText().trim()+"\n\r"+tfText.getText());try {dos.writeUTF(tfText.getText());dos.flush();tfText.setText("");//dos.close();//socket.close();} catch (IOException e1) {e1.printStackTrace();}}}public static void main(String[] args) {new ChatClient().launchFrame();}
}