java从不同类写入jTextArea

Question

只是想知道是否可以从一个单独的类附加到一个类中的jTextArea？我基本上有一个简单的类，它一直在运行计算，我想在我在自己的类中创建的GUI上查看输出。该程序通过系统执行良好。出来println但我现在想在我的文本区查看。非常感谢您的指导

更新-下面的代码是我正在运行的。讨论的领域如下（这是一个相当大的类的方法）：

System.out.println("From Server:" + sentenceFromServer);

我希望这个输出被写入一个单独的jTextArea，它位于下一个类下面的另一个类中

客户端类

public void run() {
   SocketForm form = new SocketForm();
    //File file=null;

  long startTime; // Starting time of program, in milliseconds.
  long endTime;   // Time when computations are done, in milliseconds.
  double time; 
  System.out.println("Variables Set");
  String serverName = "localhost";
   try {
    //if (args.length >= 1)
       // serverName = args[0];
  InetAddress serverIPAddress = InetAddress.getByName(serverName);

    //get server port;
    int serverPort = form.cliportNo;
    //if (args.length >= 2)
      //  serverPort = Integer.parseInt(args[1]);
    //create socket
    DatagramSocket clientSocket = new DatagramSocket();
    //get input from keybaord
    byte[] sendData = new byte[byteSize];
    //BufferedReader inFromUser = new BufferedReader(new InputStreamReader (System.in));
    //while (true){
    //String sentence = inFromUser.readLine();
    startTime = System.currentTimeMillis();
    //sendData = sentence.getBytes();
    System.out.println("About to identify image");
    String fileName = "/Users/Andrew/Desktop/pic.jpg";
    File f = new File(fileName);

    FileInputStream fis = null;
    try {
        fis = new FileInputStream(f);
        System.out.println("Total file size to read in bytes is : " + fis.available());

    } catch (IOException e) {}


 Path path = Paths.get("/Users/Andrew/Desktop/pic.jpg");
 //byte[] data = Fles.readAllBytes(path);
  sendData = Files.readAllBytes(path);   

    try {
    for( int index = 0; index < sendData.length ; index += byteSize ) {
     DatagramPacket packet = new DatagramPacket( sendData, index, Math.min( byteSize, sendData.length-index ), serverIPAddress, serverPort);
     clientSocket.send(packet);
    //DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, serverIPAddress, serverPort);

    //receive datagram
    byte[] receiveData = new byte [byteSize];

    DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
    clientSocket.receive(receivePacket);
    //print output
    String sentenceFromServer = new String(receivePacket.getData());
    System.out.println("From Server:" + sentenceFromServer);
    }
    System.out.println("The End");
    }
    catch (Exception e) {}
    //close client socket
            //clientSocket.close();
        endTime = System.currentTimeMillis();
  time = endTime - startTime;
      System.out.println("Time :" + time);
   // }
}
   catch (Exception e) {}
}

SocketForm类（GUI）

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(SocketForm.class.getName()).log(java.util.logging.Level.SEV
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new SocketForm().setVisible(true);
        }
    });
}
// Variables declaration - do not modify                     
private javax.swing.ButtonGroup buttonGroup1;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JScrollPane jScrollPane2;
private javax.swing.JTabbedPane jTabbedPane1;
public static javax.swing.JTextArea jTextArea1;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;

// End of variables declaration                   

}

Answer 1

建议：

• 为GUI类提供一个公共方法public void appendText(String text)，它只将文本字符串附加到JTextArea
• 任何希望将文本附加到JTextArea的外部类只需要对具有此方法的类具有有效引用，然后需要调用它
• 必须小心确保只在Swing事件线程EDT上调用此方法
• 由于您将从一段长时间运行的代码中执行此操作，因此您需要在Swing事件线程的下执行此长时间运行的代码。一个SwingWorker可以很好地解决这个问题。谷歌和学习教程，因为它将非常有用 您应该具体考虑使用^ {< CD2> }，并使用发布/处理方法对将字符串从服务器发送到JTestaReA，在Swing e < /b>通风> b> d/b> iSp补丁 t/b> Head或Edt.<李>
• 永远不要像上面的代码中所显示的那样，拥有一个空的catch块，catch (IOException e) {}。这相当于闭着眼睛驾驶摩托车。是的，一开始可能看起来很有趣，但结局几乎总是很糟糕

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编辑
你说：

"If it is as you say only suitable to run it on the EDT how can this be defined inside the thread which is already running?"

我知道两种方法：

1. 后台线程使用SwingWorker，并使用发布/处理方法对。查看SwingWorker教程，因为这里有详细介绍，或者
2. 使用标准的后台线程，将任何Swing调用放入传递给SwingUtilities.invokeLater(...)方法的Runnable中