我正在尝试学习套接字和ServerSockets如何在Java中工作，所以我尝试使用聊天服务器，但同时使用线程来处理每个客户端。我想我的代码需要一些新的眼睛，因为我不知道为什么它不起作用。程序启动但客户端未连接且未创建。我很确定我的客户端类有什么问题，但我不确定需要修复什么。任何帮助，即使只是一个有用的资源的链接，将非常感激。谢谢。
服务器代码
package chatbox.server;
import static java.lang.System.out;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Scanner;
public class Server {
public final static int DEFAULT_PORT = 5000;
private ServerSocket socket;
private ArrayList<Socket> clients;
public Server(int port) throws IOException {
System.out.println("Server is now online");
System.out.println("port: " + port);
this.socket = new ServerSocket(port);
System.out.println("Listening socket established");
System.out.println("Waiting for connections...");
this.clients = new ArrayList<Socket>();
while (true) {
try {
final Socket connection = this.socket.accept();
this.clients.add(connection);
Runnable incomingMsg = new Runnable() {
private InputStream inputStream = connection.getInputStream();
private InputStreamReader reader = new InputStreamReader(
inputStream);
private Scanner scanner = new Scanner(reader);
@Override
public void run() {
while (true) {
if (scanner.hasNextLine()) {
String msg = scanner.nextLine();
System.out.println("Handling message: \"" + msg
+ "\"");
notifyAllConnections(msg);
}
}
}
};
Thread thread = new Thread(incomingMsg);
thread.setUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread thread, Throwable exc) {
try {
connection.close();
} catch (IOException e1) {
e1.printStackTrace();
} finally {
clients.remove(connection);
System.out.println("Removed connection");
}
}
});
thread.start();
System.out.println("Added new connection");
} catch (IOException exc) {
System.out
.println("Error occurred.");
}
}
}
protected void notifyAllConnections(String msg) {
for (Socket sock : this.clents) {
try {
OutputStream out = sock.getOutputStream();
PrintStream printer = new PrintStream(out);
printer.println(msg);
printer.flush();
} catch (IOException exc) {
System.out.println("Message was not fully broadcast");
}
}
}
public static void main(String[] args) {
try {
Server server = new Server(
Server.DEFAULT_PORT);
} catch (IOException exc) {
System.out
.println("Could not create the server socket.");
exc.printStackTrace();
String servername = "localhost";
try {
new Client(servername, 5000);
} catch (Exception ex) {
out.println("Error" + ex.getMessage());
}
}
}
}
客户代码
package chatbox.client
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import java.io.*;
import java.util.*;
import java.net.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import static java.lang.System.out;
public class Client extends JFrame {
private PrintWriter pw;
private Scanner scanner;
private JPanel chatAndSend;
private JTextArea chatWindow;
private JScrollPane mainScroll;
private JTextArea chatText;
private JScrollPane miniScroll;
private JButton send;
private Socket client;
public Client(String servername, int port) throws Exception {
this.client = new Socket(servername, port);
this.scanner = new Scanner(new InputStreamReader(
this.client.getInputStream()));
this.pw = new PrintWriter(this.client.getOutputStream());
makeGUI();
new MessagesThread().start();
}
public void makeGUI() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setLayout(new BorderLayout());
this.chatWindow = new JTextArea(10, 20);
this.chatWindow.setEditable(false);
this.chatWindow.setLineWrap(true);
this.mainScroll = new JScrollPane(chatWindow,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
this.add(this.mainScroll, BorderLayout.NORTH);
this.chatAndSend = new JPanel();
this.chatAndSend.setLayout(new FlowLayout());
this.chatText = new JTextArea(1, 1);
this.chatText.setLineWrap(true);
this.miniScroll = new JScrollPane(chatText,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
this.chatAndSend.add(this.miniScroll);
this.send = new JButton();
this.send.setText("SEND");
this.send.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
pw.println(chatText.getText());
pw.flush();
}
});
this.chatAndSend.add(this.send);
this.add(this.chatAndSend, BorderLayout.SOUTH);
this.setVisible(true);
this.pack();
}
class MessagesThread extends Thread {
public void run() {
String line;
try {
while (true) {
line = scanner.nextLine();
chatWindow.append(line + "\n");
}
} catch (Exception exception) {
System.out.println(exception.getMessage());
}
}
}
}
答案 0 :(得分：4)
while (scanner.hasNextLine()) { 修改
我查看并运行了您的新代码。你是否看到你试图在catch块中创建一个永远不会被调用的新客户端？
最重要的是 - 在运行代码时使用调试器来查看代码正在执行或未执行的操作。添加println语句（更多）。如果你这样做了，你就会发现永远不会调用Client的构造函数，并且会知道你试着调用它的代码来查看原因。
答案 1 :(得分：0)
不确定这是否是您的问题之一，但我不知道在Server类中进行foreach循环是否安全，因为您可以从一个线程迭代并在同一时间从另一个线程添加列表，这可能是foreach循环的问题。如果我错了，请纠正我。 （或者只是从foreach中删除可能会对其造成伤害？）