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。此位置可能在应用程序生命周期内更改，并且可能位于共享网络设备上。

坦率地说，HelpSet类需要一个类加载程序，所以我想我的帮助集文件必须在类路径中，还是有其他方法？提前谢谢。

Answer 1

这应该可以通过创建和使用您自己的ClassLoader来实现。您最想使用的候选ClassLoader是URLClassLoader。

您可能有如下代码：

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，以根据共享目录获得自己的目录，而不是基于系统类路径。所以就像这样：

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));
}