异常一
只开启一个客户端，输入信息后关闭，客户端出现如下异常
根据异常说明 ChatClientFrame客户端117行
提示原因是Socket关闭
分析原因
客户端代码
while (connected) {
String str = dis.readUTF();
当窗口关闭后，Socket已经关闭，读的操作还在继续
处理这个异常，代码如下
catch (SocketException e) {
System.out.println("a client has been closed!");
}
同时，
服务端出现下边异常
解决异常
catch(EOFException e) {
System.out.println("a client has been closed,can't read message from it.");
}
异常二
开启多个客户端，关闭一个客户端后，在其他客户端中再发出信息，服务器端会出现异常
这个问题是由
for(int i=0;i<clients.size();i++) {
Client c=clients.get(i);
c.send(str);
}
此处产生逻辑bug，当一个客户端被关闭之后，这个客户端还在clients集合当中，这个被关闭的客户端还要再执行send(str)发送信息
造成
private void send(String str) {
try {
dos.writeUTF(str);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
};
}
产生异常
解决异常，在集合中把这个客户端删除掉
catch(SocketException e) {
clients.remove(this);
}
服务器端完整代码如下：
package com.swift; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.EOFException; import java.io.IOException; import java.net.BindException; import java.net.ServerSocket; import java.net.Socket; import java.net.SocketException; import java.util.ArrayList; import java.util.List; public class ChatServer { boolean started = false; ServerSocket ss = null; Socket s = null; List<Client> clients=new ArrayList<Client>(); public static void main(String[] args) { new ChatServer().fun(); } private void fun() { try { ss = new ServerSocket(8888); started = true; } catch (BindException e) { System.out.println("端口使用中......"); } catch (IOException e1) { e1.printStackTrace(); } try { while (started) { s = ss.accept(); System.out.println("a client connected success"); Client c = new Client(s); new Thread(c).start(); clients.add(c); } } catch (EOFException e) { System.out.println("client has closed."); } catch (Exception e) { e.printStackTrace(); } finally { try { ss.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } class Client implements Runnable { private Socket s; private DataInputStream dis; private DataOutputStream dos; private boolean connected = false; public Client(Socket s) { this.s = s; try { this.dis = new DataInputStream(s.getInputStream()); this.dos = new DataOutputStream(s.getOutputStream()); connected = true; } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } private void send(String str) { try { dos.writeUTF(str); } catch(SocketException e) { clients.remove(this); } catch (IOException e) { e.printStackTrace(); }; } @Override public void run() { try {//注意:要包括while循环，如果try在while循环里，则出现socket closed异常 while (connected) { String str = dis.readUTF(); System.out.println(str); for(int i=0;i<clients.size();i++) { Client c=clients.get(i); c.send(str); } // for(Iterator<Client> it=clients.iterator();it.hasNext();) { // Client c=it.next();//方法二，不可取，有同步锁 // c.send(str); // } // Iterator<Client> it=clients.iterator(); // while(it.hasNext()) { // Client c=it.next();//方法三，不可取，有同步锁,修改需要加锁（此时没修改） // c.send(str); // } } } catch(EOFException e) { System.out.println("a client has been closed,can't read message from it."); } catch (IOException e) { e.printStackTrace(); } finally { if (dis != null) { try { dis.close(); } catch (IOException e) { e.printStackTrace(); } } if(dos!=null) { try { dos.close(); } catch (IOException e) { e.printStackTrace(); } } if (s != null) { try { s.close(); } catch (IOException e) { e.printStackTrace(); } } } } } }
客户端完整代码如下：
package com.swift; import java.awt.BorderLayout; import java.awt.Color; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.IOException; import java.net.ConnectException; import java.net.Socket; import java.net.SocketException; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; public class ChatClientFrame extends JFrame { private static final long serialVersionUID = -118470059355655240L; Socket s; DataOutputStream dos; DataInputStream dis; private boolean connected = false; JLabel label_shang = new JLabel(); JLabel label_xia = new JLabel(); JTextField tf = new JTextField(38); JTextArea ta = new JTextArea(15, 50); JButton button = new JButton(); public ChatClientFrame() { setBounds(200, 200, 500, 400); setTitle("客户端聊天工具 —— 1.0"); // 对窗口进行大的布局，分为三行一列，在pBasic面板上添加三个面板shang zhong xia JPanel pBasic = new JPanel(); pBasic.setLayout(new BorderLayout());// 不设置默认也是这种布局模式 setContentPane(pBasic);// 把面板放在窗口上，不记得用this.关键字 JPanel shang = new JPanel(); JPanel zhong = new JPanel(); JPanel xia = new JPanel(); // 设置JPanel面板的大小 shang.setSize(470, 25); zhong.setSize(470, 180); xia.setSize(470, 40); pBasic.add(shang, BorderLayout.NORTH); pBasic.add(zhong, BorderLayout.CENTER); pBasic.add(xia, BorderLayout.SOUTH); shang.setBackground(Color.red); zhong.setBackground(Color.yellow); xia.setBackground(Color.blue); label_shang.setText("聊天记录"); shang.add(label_shang); ta.setLineWrap(true);// 自动换行 JScrollPane scroll = new JScrollPane(ta);// 增加滚动条，以便不增加行数 zhong.add(scroll); label_xia.setText("输入信息"); xia.add(label_xia, BorderLayout.WEST); /* * 增加功能，窗口监听事件，窗口打开时设置光标焦点在tf文本域中 */ this.addWindowListener(new WindowAdapter() { @Override public void windowOpened(WindowEvent e) { tf.requestFocus(); } }); xia.add(tf, BorderLayout.CENTER); button.setText("发送"); xia.add(button, BorderLayout.EAST); button.addActionListener(new ShareListener()); tf.addActionListener(new ShareListener()); pack(); this.addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { disconnect(); System.exit(0); } }); setVisible(true); // 创建窗体直接调用连接服务器 connect(); Thread t=new Thread(new ReceiveThread()); t.start(); } class ShareListener implements ActionListener { @Override public void actionPerformed(ActionEvent e) { String tfText1 = tf.getText(); tf.setText(""); // 当回车或发送按钮时，tfText发送到服务器 try { dos.writeUTF(tfText1); dos.flush(); } catch (IOException e1) { e1.printStackTrace(); } } } class ReceiveThread implements Runnable { @Override public void run() { try { while (connected) { String str = dis.readUTF(); System.out.println(str); ta.setText(ta.getText()+str+"\r\n"); } } catch (SocketException e) { System.out.println("a client has been closed!"); } catch (IOException e) { e.printStackTrace(); } } } public void connect() { try { s = new Socket("127.0.0.1", 8888); System.out.println("connected!"); connected=true; dos = new DataOutputStream(s.getOutputStream()); dis = new DataInputStream(s.getInputStream()); } catch (ConnectException e) { System.out.println("服务端异常........."); System.out.println("请确认服务端是否开启........."); } catch (IOException e) { e.printStackTrace(); } } public void disconnect() { try { if (dos != null) dos.close(); if(dis !=null) dis.close(); if (s != null) s.close(); } catch (IOException e) { e.printStackTrace(); } } public static void main(String[] args) { new ChatClientFrame(); } }