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();
} }