【发布时间】：2014-06-20 08:38:53
【问题描述】：
当 DrawOvalInputs.html 运行并调用 DrawOvalInputs 的类文件时，我的 JApplet 产生了错误。到目前为止，我只能将它作为一个实际的应用程序运行（这就是 main 在块引用中的原因）。
我对这个程序的目标是能够运行一个 .html 文件以在 Java 控制台上以中等安全设置启动 JApplet，但无论我做什么，它都无法运行。
在来到这里之前，我已经浏览了很多页面并进行了搜索。遗憾的是，我无法弄清楚这个 JApplet，所以如果有人能指导我正确的方向，我将不胜感激！
我的代码如下：
DrawOvalInputs.java
package drawovalapplet;
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.Graphics;
import javax.swing.JApplet;
import javax.swing.JOptionPane;
/**
* This applet inputs a number of values, and then computes the size of
* an oval with those given values.
*
* @author [Redacted]
* @version 2014-05-02, [Redacted]
*/
public class DrawOvalInputs extends JApplet
{
private static int x; //left edge of the oval
private static int y; //top edge of the oval
private static int width; //width of oval
private static int height; //height of oval
private static int windowWidth; //Holds necessary width of window.
private static int windowHeight; //Holds necessary height of window.
private static int windowBox; //Holds box form of window.
@Override
public void init()
{
try
{
/** Collect the input values. */
Input.inputAll();
/** creates dimensions for box */
windowWidth = width + x + 50;
windowHeight = height + y + 50;
/**
* If... else... function to gather data to create
* a fitting box for the oval
*/
if(windowWidth > windowHeight)
windowBox = windowWidth;
else
windowBox = windowHeight;
} catch (Input.CanceledException ex) {
System.exit(1);
}
}
@Override
public void paint(Graphics g)
{
super.paint(g);
g.drawOval(x, y, width, height);
} // end method pain
/**
* Main entry point.
* <p> Execute:
* <pre>java drawovalapplet.DrawOvalInputs</pre>
*
* @param args not used.
*/
/*public static void main(String args[])
{
Frame frame = new Frame("DrawOvalInputs");
DrawOvalInputs drawOval = new DrawOvalInputs();
drawOval.init();
drawOval.start();
frame.add(drawOval);
frame.setSize(drawOval.windowBox, drawOval.windowBox);
frame.setVisible(true);
}*/
//------------------------------- Nested Classes --------------------------------
/**
* Enumeration of the name and value of the input values.
*/
private enum Input
{
/**
* Message for the entering the x coordinate.
*/
XVALUE("Enter the argument for the x coordinate of the upper left corner of the oval to be drawn:"),
/**
* Message for the entering the y coordinate.
*/
YVALUE("Enter the argument for the y coordinate of the upper left corner of the oval to be drawn:"),
/**
* Message for entering the width.
*/
WIDTHVALUE("Enter the desired width of the oval to be drawn:"),
/**
* Message for entering the height.
*/
HEIGHTVALUE("Enter the desired height of the oval:");
/**
* String to use in messages (from the constructor).
*/
protected String invitation;
/**
* String to use for error messages.
*/
protected String error = "Not an integer value--please re-enter:";
/**
* Value of this {@literal <variable>}.
*/
protected int value;
/**
* @param label string to use in messages
*/
Input(String invitation)
{
this.invitation = invitation;
}
public static void inputAll() throws CanceledException
{
/* Decide which input value is currently being used. */
int count = 0;
/* Collect the input numbers. */
for(Input input : Input.values())
{
/* Set up the invitation to enter each number. */
String message = input.invitation;
/* Loop until the user inputs an acceptably formatted number. */
while(true) // repetition environment
{
String response;
/* Null return from the JOptionPane indicates CANCEL was pressed. */
if( (response = JOptionPane.showInputDialog(message)) == null)
throw new CanceledException();
message = input.error; // just in case
try
{
input.value = Integer.parseInt(response);
break; // success in acquiring value
}
catch(NumberFormatException nfe) {}// ignore all, and try again
}
count++;
if(count == 1)
x = input.value;
else if(count == 2)
y = input.value;
else if (count == 3)
width = input.value;
else if (count == 4)
height = input.value;
else
System.out.println("Error. Revise.");
}
}
@SuppressWarnings("serial")
public static class CanceledException extends Exception {}
}
}
DrawOvalInputs.html 我已经用 DrawOvalInputs.java 和下面的那个以及 .class 来运行它。
<html>
<body>
<applet code=drawovalapplet.DrawOvalInputs.java width=400 height=400>
</applet>
</body>
</html>
谢谢！
【问题讨论】：
-
更新： 在查看了用于创建小程序的 Netbeans 页面（如下）后，我尝试了使用 JDK 1.8 和 1.7 以 JApplet 和 Applet 格式呈现的所有格式考虑到可能有什么不对劲或损坏。两个 JDK 都重新安装以防万一，但仍然没有任何功能。 netbeans.org/kb/docs/web/applets.html
-
你为什么评论
/*public static void main(String args[]) -
我相信 JApplet 应该能够在浏览器中运行，并被初始化为 JApplet 而不是常规桌面应用程序。或者至少，从它们被访问和运行的两种不同形式中。如果我理解正确，它会通过浏览器如下所述的覆盖方法运行。
public void init();public void start();public void stop();public void init();public void destroy(); -
public void paint();而不是第二个初始化，对不起。 -
“我对这个程序的目标是能够运行一个 .html 文件来启动 JApplet..” 对于部署 Java 桌面应用程序，最好的选择是通常安装应用程序。使用Java Web Start。 JWS 适用于 Windows、OS X 和 *nix。
标签： java html netbeans applet japplet