java - Java中TCP的几个问题

Question

好的，首先它会连接到服务器，所以连接没有问题，下面的代码显示连接并向服务器发送消息，当我单击运行时它不会打开 JFrame，窗口我可以在哪里看到我的工具...我还试图将我从 jMessage.getText 获得的内容发送到 ows，但我在这一行收到错误消息:

String process = jMessage.getText();

我还想调用 osw.write(process);仅当我单击 bSend 按钮时，如何在 main 方法中使用它？请看一下代码，还记得第一个问题，我的 JFrame 不会在新窗口中打开显示我的工具，它只是在 netbeans 控制台打印出 System.out.println:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package tcpservidor;

import java.io.*;
import java.net.InetAddress;
import java.net.Socket;

/**
 *
 * @author Damage
 */
public class TeKServer extends javax.swing.JFrame {

/**
 * Creates new form TeKServer
 */
public TeKServer() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    jLabel1 = new javax.swing.JLabel();
    jScrollPane1 = new javax.swing.JScrollPane();
    textArea = new javax.swing.JTextArea();
    jMessage = new javax.swing.JTextField();
    bSendMessage = new javax.swing.JButton();
    jLabel2 = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jLabel1.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
    jLabel1.setText("Chat Client");

    textArea.setColumns(20);
    textArea.setRows(5);
    textArea.setEnabled(false);
    jScrollPane1.setViewportView(textArea);

    bSendMessage.setText("Send");
    bSendMessage.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            bSendMessageActionPerformed(evt);
        }
    });

    jLabel2.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
    jLabel2.setText("Message");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addGap(0, 0, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                    .addComponent(jLabel1)
                    .addGap(294, 294, 294))
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                    .addComponent(jLabel2)
                    .addGap(303, 303, 303))))
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addComponent(jScrollPane1)
                        .addComponent(jMessage))
                    .addContainerGap())
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                    .addGap(0, 291, Short.MAX_VALUE)
                    .addComponent(bSendMessage, javax.swing.GroupLayout.PREFERRED_SIZE, 81, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(286, 286, 286))))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 319, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(jLabel2)
            .addGap(3, 3, 3)
            .addComponent(jMessage, javax.swing.GroupLayout.PREFERRED_SIZE, 61, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(bSendMessage)
            .addContainerGap())
    );

    pack();
}// </editor-fold>

private void bSendMessageActionPerformed(java.awt.event.ActionEvent evt) {
    // TODO add your handling code here:


}

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /*
     * Set the Nimbus look and feel
     */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /*
     * If Nimbus (introduced in Java SE 6) is not available, stay with the
     * default look and feel. For details see
     * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(TeKServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(TeKServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(TeKServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(TeKServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>
    /** Define a host server */
        String host = "192.168.0.8";
        /** Define a port */
        int port = 7777;

        StringBuffer instr = new StringBuffer();
        String TimeStamp;
        System.out.println("SocketClient initialized");
        try {
        /** Obtain an address object of the server */
        InetAddress address = InetAddress.getByName(host);
        /** Establish a socket connetion */
        Socket connection = new Socket(address, port);
        System.out.println("Connection Established!");
        /** Instantiate a BufferedOutputStream object */
        BufferedOutputStream bos = new BufferedOutputStream(connection.
        getOutputStream());

        /** Instantiate an OutputStreamWriter object with the optional character
        * encoding.
        */
        OutputStreamWriter osw = new OutputStreamWriter(bos, "US-ASCII");
        TimeStamp = new java.util.Date().toString();

        String process = jMessage.getText();
        /** Write across the socket connection and flush the buffer */
        osw.write(process);
        osw.flush();
         /** Instantiate a BufferedInputStream object for reading
        /** Instantiate a BufferedInputStream object for reading
        * incoming socket streams.
        */

        BufferedInputStream bis = new BufferedInputStream(connection.
            getInputStream());
        /**Instantiate an InputStreamReader with the optional
        * character encoding.
        */

        InputStreamReader isr = new InputStreamReader(bis, "US-ASCII");

        /**Read the socket's InputStream and append to a StringBuffer */
        int c;
        while ( (c = isr.read()) != 13)
            instr.append( (char) c);

        /** Close the socket connection. */
        connection.close();
        System.out.println(instr);
        }
        catch (IOException f) {
        System.out.println("IOException: " + f);
        }
        catch (Exception g) {
        System.out.println("Exception: " + g);
        }

    /*
     * Create and display the form
     */
    java.awt.EventQueue.invokeLater(new Runnable() {

        @Override
        public void run() {
            new TeKServer().setVisible(true);
        }
    });
}
// Variables declaration - do not modify
private javax.swing.JButton bSendMessage;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
public javax.swing.JTextField jMessage;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea textArea;
// End of variables declaration
}

Answer 1

线

String process = jMessage.getText();

导致编译错误，因为它是在 static main 方法中声明的，其中 jMessage 是一个实例变量。由于您在 main 方法中有很多代码，我建议将其提取到 launchApp 方法中并像这样调用它:

new TeKServer().launchApp();

在新的 launchApp() 方法中，您将替换

java.awt.EventQueue.invokeLater(new Runnable() {

    @Override
    public void run() {
        new TeKServer().setVisible(true);
    }
});

与

setVisible(true);

I'd like to call osw.write(process); ONLY when I click the bSend button

如果您想这样做，您可以将 osw 维护为全局成员变量但是无限期地保持套接字打开是通常是一种不好的方法。建议仅在需要时打开套接字，写入并关闭。