MessengerServer.java package?pro4; import?java.net.*; import?java.io.*; import?java.util.*; public?class?MessengerServer?{ public?void?startServer(){ try{ ServerSocket?serverSocket=new?ServerSocket(8000,100); System.out.println("服務器已啟動"); while(true){ Socket?clientSocket=serverSocket.accept(); System.out.println("已接受到客戶來自："+clientSocket.getInetAddress()); ChatHandler?handler=new?ChatHandler(clientSocket); handler.start(); } } catch(IOException?ioException){ ioException.printStackTrace(); } } public?static?void?main(String[]?args)?{ MessengerServer?application=new?MessengerServer(); application.startServer(); } } ChatHandler.java package?pro4; import?java.net.*; import?java.io.*; import?java.util.*; public?class?ChatHandler?implements?Runnable{ protected?Socket?socket; protected?ObjectInputStream?dataIn; protected?ObjectOutputStream?dataOut; protected?Thread?listener; protected?static?Vector?handlers=new?Vector(); private?boolean?keepListening=true; public?ChatHandler(Socket?socket){ this.socket=socket; } public?synchronized?void?start(){ if(listener==null){ try{ dataIn=new?ObjectInputStream(socket.getInputStream()); dataOut=new?ObjectOutputStream(socket.getOutputStream()); listener=new?Thread(this); listener.start(); }catch(IOException?ioException){ ioException.printStackTrace(); } } } public?synchronized?void?stop(){ if(listener!=null){ try{ if(listener!=Thread.currentThread()) listener.interrupt(); listener=null; dataOut.close(); socket.close(); }catch(IOException?ignored){ } } } public?void?run(){ String?message=""; try{ handlers.addElement(this); while(keepListening){ message=(String)dataIn.readObject(); if(message.equals("DISCONNECT")){ dataOut.writeObject(message); dataOut.flush(); stopListening(); }else broadcast(message); } }catch(ClassNotFoundException?classNotFoundException){ }catch(EOFException?ignored){ }catch(IOException?ex){ if(listener==Thread.currentThread()) ex.printStackTrace(); }finally{ handlers.removeElement(this); } try{ dataIn.close(); }catch(IOException?ioException){ ioException.printStackTrace(); } stop(); } protected?void?broadcast(String?message){ synchronized?(handlers){ Enumeration?enumer=handlers.elements(); while(enumer.hasMoreElements()){ ChatHandler?handler=(ChatHandler)enumer.nextElement(); try{ handler.dataOut.writeObject(message); handler.dataOut.flush(); }catch(IOException?ex){ handler.stop(); } } } } public?void?stopListening(){ keepListening=false; } } MessengerClient.java package?pro4; import?java.awt.*; import?java.awt.event.*; import?java.net.*; import?java.io.*; import?javax.swing.*; import?javax.swing.border.*; public?class?MessengerClient??extends?JFrame?implements?Runnable{ private?JTextArea?messageArea; private?JTextArea?inputArea; private?JButton?connectButton; private?JButton?disconnectButton; private?JButton?sendButton; private?JLabel?statusBar; private?String?userName; private?String?chatServer; private?ObjectOutputStream?output; private?ObjectInputStream?input; private?Socket?client; private?boolean?connected; private?Thread?processConnection; public?MessengerClient(String?host){ super("聊天客戶端"); chatServer=host; connectButton=new?JButton("登錄"); ActionListener?connectListener=new?ConnectListener(); connectButton.addActionListener(connectListener); disconnectButton=new?JButton("退出"); disconnectButton.setEnabled(false); ActionListener?disconnectListener=new?DisconnectListener(); disconnectButton.addActionListener(disconnectListener); messageArea=new?JTextArea(); messageArea.setEditable(false); messageArea.setWrapStyleWord(true); messageArea.setLineWrap(true); JPanel?messagePanel=new?JPanel(); messagePanel.setLayout(new?BorderLayout(10,10)); messagePanel.add(new?JScrollPane(messageArea),BorderLayout.CENTER); inputArea=new?JTextArea(4,20); inputArea.setWrapStyleWord(true); inputArea.setLineWrap(true); inputArea.setEditable(false); sendButton=new?JButton("發送"); sendButton.setEnabled(false); sendButton.addActionListener(new?ActionListener(){ public?void?actionPerformed(ActionEvent?event){ sendMessage(userName+">"+inputArea.getText()); inputArea.setText(""); } }); JPanel?buttonPanel=new? JPanel(); buttonPanel.setLayout(new?GridLayout(3,1)); buttonPanel.add(sendButton); buttonPanel.add(connectButton); buttonPanel.add(disconnectButton); Box?box=new?Box(BoxLayout.X_AXIS); box.add(new?JScrollPane(inputArea)); box.add(buttonPanel); messagePanel.add(box,?BorderLayout.SOUTH); statusBar=new?JLabel("離線"); statusBar.setBorder(new?BevelBorder(BevelBorder.LOWERED)); Container?container=getContentPane(); container.add(messagePanel,?BorderLayout.CENTER); container.add(statusBar,BorderLayout.SOUTH); addWindowListener(new?WindowAdapter(){ public?void?windowClosing(WindowEvent?event){ if(connected){ sendMessage("DISCONNECT"); do{ }while(connected); } System.exit(0); } }); } private?void?sendMessage(String?message){ try{ output.writeObject(message); output.flush(); }catch(IOException?ioException){ ioException.printStackTrace(); } } public?void?run(){ String?message=""; do{ try{ message=(String)input.readObject(); }catch(ClassNotFoundException?classNotFoundException){ displayMessage("\n收到異常對象類型"); }catch(EOFException?eofException){ System.err.println("連接終止"); }catch(IOException?ioException){ ioException.printStackTrace(); } if(message.equals("DISCONNECT")){ try{ input.close(); output.close(); client.close(); }catch(IOException?ioException){ ioException.printStackTrace(); } connected=false; } else?displayMessage(message+"\n"); }while(connected); } private?class?ConnectListener?implements?ActionListener{ public?void?actionPerformed(ActionEvent?event){ try{ client=new?Socket(chatServer,8000); output=new?ObjectOutputStream(client.getOutputStream()); output.flush(); input=new?ObjectInputStream(client.getInputStream()); }catch(IOException?ioException){ ioException.printStackTrace(); } userName=JOptionPane.showInputDialog("請輸入你的用戶名"); messageArea.setText(""); connectButton.setEnabled(false); disconnectButton.setEnabled(true); sendButton.setEnabled(true); inputArea.setEditable(true); inputArea.requestFocus(); statusBar.setText("在線:"+userName); connected=true; processConnection=new?Thread(MessengerClient.this); processConnection.start(); } } private?class?DisconnectListener?implements?ActionListener{ public?void?actionPerformed(ActionEvent?event){ sendMessage("DISCONNECT"); sendButton.setEnabled(false); disconnectButton.setEnabled(false); inputArea.setEditable(false); connectButton.setEnabled(true); statusBar.setText("離線"); } } private?void?displayMessage(final?String?messageToDisplay){ SwingUtilities.invokeLater(new?Runnable(){ public?void?run(){ messageArea.append(messageToDisplay); messageArea.setCaretPosition(messageArea.getText().length()); } }); } public?static?void?main(String[]?args)?{ MessengerClient?application; if(args.length==0) application=new?MessengerClient("127.0.0.1"); else application=new?MessengerClient(args[0]); application.setSize(300,400); application.setResizable(false); application.setVisible(true); } } 請問怎么在這個基礎上實現細聊，就是能看到在線的人，然后點擊進行私聊