Question

可能重复：
HTML does not display my Java Applet with a JLabel

我有Java Applet的下一个代码源：

package m2mcom.web;
import m2mcom.entities.AutomatedTelnetClient;
import javax.swing.JApplet;
import javax.swing.SwingUtilities;
import javax.swing.JLabel;

public class Displaytext extends JApplet {
//Called when this applet is loaded into the browser.
public void init() {
    //Execute a job on the event-dispatching thread; creating this applet's GUI.
    try {
        SwingUtilities.invokeAndWait(new Runnable() {
            public void run() {
                AutomatedTelnetClient telnet = new AutomatedTelnetClient();
                String answer = telnet.request();
                JLabel lbl = new JLabel(answer);
                add(lbl);
            }
        });
    } catch (Exception e) {
        System.err.println("createGUI didn't complete successfully");
    }
}
}

telnet请求在AutomatedTelnetClient类中生成，一旦获得响应，会话也将关闭。当我执行.html文件时，没有绘制任何内容，屏幕为空。任何人都知道为什么会这样做。是否有其他方法可以将字符串添加到Applet中？难道问题是来自SwingUtilities的inovkeAndWait？

这是HTML：

<HTML>
<HEAD>
</HEAD>
<BODY>
<div >
<APPLET CODE="m2mcom.web.Displaytext.class" WIDTH="800" HEIGHT="500">
</APPLET>
</div>
</BODY>
</HTML>

Answer 1

尽量不要运行

AutomatedTelnetClient telnet = new AutomatedTelnetClient();

在SwingUtilities线程中。 b / c telnet请求很可能是异步调用。尝试直接运行上面的代码而不使用线程，看看你得到了什么。

--- --- UPDATE

另一个问题可能是我的代码中的最后一行，它将标签添加到applet的contentPane组件中。这可能是问题所在。

如果这两个修复程序不起作用，则很可能您的 AutomatedTelnetClient 类逻辑中存在问题。

package m2mcom.web;
import m2mcom.entities.AutomatedTelnetClient;
import javax.swing.JApplet;
import javax.swing.SwingUtilities;
import javax.swing.JLabel;

public class Displaytext extends JApplet {
//Called when this applet is loaded into the browser.
public void init() {
    //Execute a job on the event-dispatching thread; creating this applet's GUI.
    try {

                AutomatedTelnetClient telnet = new AutomatedTelnetClient();
                String answer = telnet.request();
                JLabel lbl = new JLabel(answer);
                getContentPane().add(lbl);



    } catch (Exception e) {
        System.err.println("createGUI didn't complete successfully");
    }
}
}

Java Applet SwingUtilities空屏幕

1 个答案: