JavaHelp:是否可以从类路径之外的位置加载帮助？

Question

我希望能够从类路径之外的自定义位置加载 javahelp 内容。此位置可能会在应用程序的生命周期中发生变化，并且可能位于共享网络设备上。

不幸的是，HelpSet 类需要类加载器，所以我猜我的帮助集文件必须位于类路径中，或者还有其他方法吗？提前致谢。

Answer 1

这应该可以通过创建和使用您自己的类加载器来实现。您最有可能想要使用的候选类加载器是 URLClassLoader .

您的代码可能如下所示:

JHelp helpViewer = null;
try {
  // Get the classloader of this class.
  ClassLoader cl = JavaHelpTest.class.getClassLoader();
  // Use the findHelpSet method of HelpSet to create a URL referencing the helpset file.
  // Note that in this example the location of the helpset is implied as being in the same
  // directory as the program by specifying "jhelpset.hs" without any directory prefix,
  // this should be adjusted to suit the implementation.
  URL url = HelpSet.findHelpSet(cl, "jhelpset.hs");
  // Create a new JHelp object with a new HelpSet.
  helpViewer = new JHelp(new HelpSet(cl, url));
}

您需要更改获取 ClassLoader 的行，以根据共享目录获取您自己的 ClassLoader，而不是基于系统类路径的行。所以像这样:

JHelp helpViewer = null;
try {
  // Get the class loader of the shared directory. Note that directories are
  // required to have a trailing '/' or '\'.
  ClassLoader cl = new URLClassLoader(new URL[] {new URL("file:///path/to/share/")});
  // Use the findHelpSet method of HelpSet to create a URL referencing the helpset file.
  // Note that in this example the location of the helpset is implied as being in the same
  // directory as the program by specifying "jhelpset.hs" without any directory prefix,
  // this should be adjusted to suit the implementation.
  URL url = HelpSet.findHelpSet(cl, "jhelpset.hs");
  // Create a new JHelp object with a new HelpSet.
  helpViewer = new JHelp(new HelpSet(cl, url));
}