加载:未找到类 MyApplet:java.lang.ClassNotFoundException.为什么我会得到这个，当包中有类文件时? [英] load: class MyApplet not found : java.lang.ClassNotFoundException. Why am i getting this,when the class file is there in the package?

问题描述

当我尝试运行小程序时出现以下异常:

I get the following exception when i try to run the applet :

load: class MyApplet not found.
java.lang.ClassNotFoundException: MyApplet
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.io.BufferedInputStream.fill(Unknown Source)
at java.io.BufferedInputStream.read1(Unknown Source)
at java.io.BufferedInputStream.read(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.net.HttpURLConnection.getResponseCode(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader.getBytes(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader.access$000(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
... 9 more
Exception: java.lang.ClassNotFoundException: MyApplet

小程序代码:

import javax.swing.*;
import java.awt.*;

public class MyApplet extends JApplet {

public JFrame frame;
public JPanel panel;
public JButton button;

public void init() {
    frame = new JFrame();
    panel = new JPanel();
    button = new JButton("click me ");
    panel.setBackground(Color.RED);
    panel.add(button);
    frame.add(panel);
    frame.setSize(300,300);
    frame.setVisible(true);
}   
}

html 代码:

<applet code="MyApplet" codebase="AppletPackage" archive="JAR.jar" height="800" width="800">

JAR.jar 文件包含一个包 Appletpackage，这个包包含一个名为 MyApplet.class

为什么我会收到此异常?我犯了什么错误?

Why do i get this exception ? Whare have i made the mistake ?

推荐答案

archive 参数相对于 codebase 参数进行解析.因此，在您的情况下，插件将查找文件 AppletPackage/JAR.jar 中包含的文件 MyApplet.class.

The archive parameter is resolved relative to the codebase parameter. So in your case the plugin will look for a file MyApplet.class included in a file AppletPackage/JAR.jar.

您应该将其更改为以下内容:

You should change this to the following:

<applet code="AppletPackage.MyApplet" archive="JAR.jar" height="800" width="800">

这将解析为 JAR.jar 内的 AppletPackage/MyApplet.class 与 HTML 文件位于同一目录中.

This will resolve to AppletPackage/MyApplet.class inside JAR.jar in the same directory as the HTML file.

这篇关于加载:未找到类 MyApplet:java.lang.ClassNotFoundException.为什么我会得到这个，当包中有类文件时?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！