Java 单服务器和多客户端的通信死锁

我是Java初学者，正在编写聊天服务器应用程序。该应用程序有助于n个客户端之间的聊天

当前问题 在我下面的代码中，Chatinterface classis是客户端类。在我打开Chatinterfaceclass的两个实例之后，当我试图通过在文本区域中输入消息进行通信时。我在另一个客户端实例窗口中没有收到消息，反之亦然。要么我的套接字无法通信，要么存在其他问题

预期产量

两个客户端都必须通信，并且消息必须显示在各自的窗口中

谁能告诉我出了什么问题，我在哪里可以更正代码

无论如何，我粘贴我的客户端和服务器代码以进行详细分析

package stack;

import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SpringLayout;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
class Chatinterface implements ActionListener {
    private JFrame frame;
    JTextArea textArea_1;
    JTextArea textArea_2;
    JButton btnNewButton;
    JButton btnNewButton_1;
    Socket client;
    BufferedReader read;
    PrintWriter write;
    String getmsg;
    String gettext;
    public Chatinterface(){
        communicate();
        displaygui();
    }
    private void communicate() {
        // TODO Auto-generated method stub
        try {
            client = new Socket("localhost",3420);
            read = new BufferedReader(new InputStreamReader(client.getInputStream()));
            write = new PrintWriter(client.getOutputStream(),true);
            if(getmsg!=null)
            {
                while(true)
                {
                    textArea_2.setText(getmsg);
                }
            }

        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private void displaygui() {
        frame = new JFrame();
        frame.setResizable(false);
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        SpringLayout springLayout = new SpringLayout();
        frame.getContentPane().setLayout(springLayout);
        textArea_1 = new JTextArea();
        springLayout.putConstraint(SpringLayout.NORTH, textArea_1, 171, SpringLayout.NORTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.WEST, textArea_1, 10, SpringLayout.WEST, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.SOUTH, textArea_1, -10, SpringLayout.SOUTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.EAST, textArea_1, 340, SpringLayout.WEST, frame.getContentPane());
        frame.getContentPane().add(textArea_1);
        textArea_2 = new JTextArea();
        textArea_2.setWrapStyleWord(true);
        textArea_2.setEditable(false);
        springLayout.putConstraint(SpringLayout.NORTH, textArea_2, 10, SpringLayout.NORTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.WEST, textArea_2, 0, SpringLayout.WEST, textArea_1);
        springLayout.putConstraint(SpringLayout.SOUTH, textArea_2, 160, SpringLayout.NORTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.EAST, textArea_2, 0, SpringLayout.EAST, textArea_1);
        frame.getContentPane().add(textArea_2);
        btnNewButton = new JButton("Send");
        springLayout.putConstraint(SpringLayout.NORTH, btnNewButton, -76, SpringLayout.SOUTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.WEST, btnNewButton, 5, SpringLayout.EAST, textArea_1);
        springLayout.putConstraint(SpringLayout.SOUTH, btnNewButton, -27, SpringLayout.SOUTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.EAST, btnNewButton, 82, SpringLayout.EAST, textArea_1);
        frame.getContentPane().add(btnNewButton);
        btnNewButton.addActionListener(this);
        btnNewButton.setActionCommand("S");
        btnNewButton_1 = new JButton("Logout");
        springLayout.putConstraint(SpringLayout.NORTH, btnNewButton_1, 50, SpringLayout.NORTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.WEST, btnNewButton_1, -65, SpringLayout.EAST, btnNewButton);
        springLayout.putConstraint(SpringLayout.SOUTH, btnNewButton_1, 108, SpringLayout.NORTH, frame.getContentPane());
        springLayout.putConstraint(SpringLayout.EAST, btnNewButton_1, 0, SpringLayout.EAST, btnNewButton);
        frame.getContentPane().add(btnNewButton_1);
        btnNewButton_1.addActionListener(this);
        btnNewButton_1.setActionCommand("L");
        frame.setVisible(true);
    }
    public static void main(String args[])
    {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    new Chatinterface();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {

        if(arg0.getActionCommand().equals("S"))
        {   
            String gettext2;
            gettext2 = textArea_1.getText();
            textArea_2.append(gettext2);
            textArea_1.setText("");
            write.println(gettext2);
        }

        if(arg0.getActionCommand().equals("L")){
            try {
                read.close();
                write.close();
                client.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

下面是服务器类的代码

package stack;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.*;
public class Server1  {
    public static void main(String[] args) throws Exception {
        Socket s;
        ServerSocket server = new ServerSocket(3420);
        while(true)
        {
            s = server.accept();
            Handler handler1 = new Handler(s);
            Thread t1 = new Thread(handler1);
            t1.start();


        }
    }
}

下面是处理程序类

package stack;

import java.io.*;
import java.net.*;

public class Handler implements Runnable {

    Socket s;

    String getmsg = null;
    String sendmsg;

    public Handler(Socket s) {
        this.s = s;

    }

    public void run() {

        try {
            BufferedReader reader1;
            PrintWriter writer1;
            reader1 = new BufferedReader(new InputStreamReader(
                    s.getInputStream()));
            writer1 = new PrintWriter(s.getOutputStream(), true);
            sendmsg = reader1.readLine();

            while (true) {
                if (reader1 == null) {

                    s.close();
                } else {
                    writer1.println(sendmsg);
                }
            }

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

---

您的代码很难阅读和理解。尝试使用相关的变量名。试着专注于与问题相关的代码

我不知道你的问题是什么，但我肯定这里有问题：

e.getActionCommand() == "s"

这里呢

if (e.getActionCommand() == "L")

在测试指针相等性时，这些都是不正确的，而不是内容读取更多

所以写下：

e.getActionCommand().equals("s")

及

对于任何进一步的问题：

使用调试器 使用日志

---

正如ben75所说，代码很难阅读，并且有一些错误。让我提供一些建议，以帮助您：

1-不要在构造函数中创建功能。这是您在Chatinterface中执行的操作。构造函数应该只创建对象。然后您可以添加一个名为execute的方法来完成这项工作

private void execute()
{
    ...
}

2-我还没有测试通信部分，但它应该可以在客户端和服务器之间正常通信。我运行Chatinterface，代码正确到达这一行：

write.println(gettext2);

3-您没有看到消息的错误原因是，在构造函数中，它正在调用Communication和displaygui。Communication中的代码应显示从服务器收到的消息：

        if(getmsg!=null)
        {
            while(true)
            {
                textArea_2.setText(getmsg);
            }
        }

但这段代码在开始时只执行一次，getmsg为null，执行控制再也不会回到这段代码。 我假设您试图在客户机中创建一个不同的线程，该线程将执行此代码并进入无限循环

如果您对通信客户端服务器有疑问，可以使用Wireshark或tcpdump嗅探通信

---

这里没有死锁。

我已经编辑了我的问题，并在上面提供了清晰的描述。我还简化了代码。

        if(getmsg!=null)
        {
            while(true)
            {
                textArea_2.setText(getmsg);
            }
        }