Java 小程序，加载本机 dll 时出现问题

发布于 2024-10-25 20:54:11 字数 1667 浏览 1 评论 0原文

我正在编写一个 Java 小程序，它加载在非托管 C++ 中创建的 dll。我正在编写一些基本测试来加载它。

代码如下：

DLL：

#define DllExport _declspec(dllexport)
DllExport int calc();


DllExport int calc() {
return 1000;
}

小程序：

import java.applet.*;
import java.awt.*;


public class app extends Applet {

   int width, height;
   private native int calc();

   public void init() {
   try {
       System.loadLibrary("appletdll.dll");
       setBackground( Color.black );
   }
   catch(Exception e) {
       setBackground( Color.red );
               // for debugging, is there another way to for example print 
               // exception messages in an applet?
   }

   //width = getSize().width;
   width = calc();
   height = getSize().height;
  }

  public void paint( Graphics g ) {
     g.setColor( Color.green );
     for ( int i = 0; i < 10; ++i ) {
         g.drawLine( width, height, i * width / 10, 0 );
     }
  }
}

运行小程序的 HTML：

<html>
<head><title>simple page</title></head>
<body>

<applet width=400 height=400 code="app.class" archive="apptest.jar"> </applet> 

</body>
</html>

在 Firefox 中运行时，我得到的只是黑色的 400x400 背景。在 applerviewer 中运行时，我在 calc() 上收到 UnsatisfiedLinkError。

使用本指南对 .jar 进行签名： http://wiki.plexinfo.net/index.php?title=How_to_sign_JAR_files

在我的文件夹中有：应用程序类，应用测试.jar, 小程序dll.dll, 小程序.htm，
myKeystore

我可能做错了很多，我只是想让一些基础知识发挥作用。我一直在查看 applet+dll 指南，但它们大多已经过时了。如果有什么不清楚的地方，尽管问。

谢谢

原文

I am writing a Java applet which loads dll's created in unmanaged C++. I am writing some basic test to get it loading.

Here's the code:

The DLL:

#define DllExport _declspec(dllexport)
DllExport int calc();


DllExport int calc() {
return 1000;
}

The applet:

import java.applet.*;
import java.awt.*;


public class app extends Applet {

   int width, height;
   private native int calc();

   public void init() {
   try {
       System.loadLibrary("appletdll.dll");
       setBackground( Color.black );
   }
   catch(Exception e) {
       setBackground( Color.red );
               // for debugging, is there another way to for example print 
               // exception messages in an applet?
   }

   //width = getSize().width;
   width = calc();
   height = getSize().height;
  }

  public void paint( Graphics g ) {
     g.setColor( Color.green );
     for ( int i = 0; i < 10; ++i ) {
         g.drawLine( width, height, i * width / 10, 0 );
     }
  }
}

The HTML running the applet:

<html>
<head><title>simple page</title></head>
<body>

<applet width=400 height=400 code="app.class" archive="apptest.jar"> </applet> 

</body>
</html>

All I am getting when running in Firefox is a black 400x400 background.
When running in applerviewer, I get an UnsatisfiedLinkError on calc().

The .jar is signed using this guide:
http://wiki.plexinfo.net/index.php?title=How_to_sign_JAR_files

In the folder I have:
app.class,
apptest.jar,
appletdll.dll,
applet.htm,
myKeystore

I am probably doing alot wrong, I am just trying to get some basics working. I've been looking at applet+dll guides but they are mostly outdated.
If there is anything that is not clear, just ask.

Thanks

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