如何在 Java 小程序中正确指定代码库和存档? [英] How to specify correctly codebase and archive in Java applet?
问题描述
我使用 firefox 版本 > 3.5 (3.5.,3.6.,4.*) 并且我尝试指定 archive 和 codebase 属性正确，但它不起作用.我的小程序的主类位于 archive 中，在运行时加载的一些必要类位于 codebase 中.如果我仅指定 archive，则小程序已加载，但 codebase 中的类丢失.如果我指定 archive 和 codebase 则无法加载小程序.看起来小程序尝试从 codebase 文件夹加载主类，而不查看 archive 文件.
I use firefox version > 3.5 (3.5.,3.6.,4.*) and I try to specify archive and codebase property correctly but it doesn't work. My main class for applet is situated in the archive and some necessary classes that are loaded during runtime are situated in the codebase. If I specify only the archive then the applet is loaded but the classes from codebase are missing. If I specify the archive and the codebase then the applet can't be loaded. It looks like applet try to load main class from codebase folder and doesn't look into the archive file.
<html>
<body>
<applet width=600 height=300 code="MyClass.class"
type="application/x-java-applet;jpi-version=6"
archive="http://myurl.com/archive/myjar.jar"
codebase="http://myurl.com/classes">
no applet
</applet>
</body>
</html>
主类位于 http://myurl.com/archive/myjar.jar 中，运行时类位于在 http://myurl.com/classes 中.
Main class is situated in http://myurl.com/archive/myjar.jar and runtime classes are situated in http://myurl.com/classes.
推荐答案
属性 codebase 指定小程序的基本 URL - 包含小程序代码的目录.它用于在 archive 属性中搜索 jar 文件，以便相对于 codebase 搜索 archive 属性中的所有 jar.
所以.当您将 archive="http://myurl.com/archive/myjar.jar" 和 codebase="http://myurl.com/classes" 一起使用时意思是:找到 "http://myurl.com/archive/myjar.jar" 在"http://myurl.com/classes" 文件夹.
IE.完整的搜索路径是 "http://myurl.com/classes/http://myurl.com/archive/myjar.jar".当然也找不到！
此外，如果没有 codebase 属性，则无法找到其 jar 文件未在 archive 属性中指定的类.IE.如果没有 codebase，则无法在 "http://myurl.com/中找到您的课程类"文件夹.
Attribute codebase specifies the base URL of the applet - the directory that contains the applet's code. It is used while searching jar files in archive attribute, in such a way that all jars in archive attribute are searched relative to codebase.
So. When you use archive="http://myurl.com/archive/myjar.jar" and codebase="http://myurl.com/classes" together it means: find "http://myurl.com/archive/myjar.jar" in "http://myurl.com/classes" folder.
I.e. the full search path is "http://myurl.com/classes/http://myurl.com/archive/myjar.jar". And of course it can't be found!
Also, classes, whose jar-files aren't specified in the archive attribute, can't be found without codebase attribute. I.e. if there is no codebase then there is no way to find your classes in "http://myurl.com/classes" folder.
您可以在使用 Applet 标签部署教程中找到更多详细信息.
You can find more details in the Deploying With the Applet Tag tutorial.
我建议以下解决方案:
- 将
myjar.jar放在http://myurl.com/classes文件夹中； - 假设您的 MyClass.class 位于 default 包中，并且位于 "http://myurl.com/archive/myjar.jar"，下面的代码应该可以工作:
- Place
myjar.jarin thehttp://myurl.com/classesfolder; - Assuming your MyClass.class is in default package, and in the "http://myurl.com/archive/myjar.jar", the following code should work:
<小时>
<html>
<body>
<applet width=600 height=300 code="MyClass"
type="application/x-java-applet;jpi-version=6"
archive="myjar.jar"
codebase="http://myurl.com/classes">
no applet
</applet>
</body>
</html>
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