您需要做的就是遍历类型层次结构，直到找到所需的内容或用尽所有要检查的内容.这可以通过递归来完成，也可以通过循环来完成

What you'll need to do is walk the types hierarchy, until you either find what you want, or run out of things to check. That can be done with recursion, or could be done with a loop

您需要的关键方法是您的代码希望是这样的:

Your code would want to be something like:

// Define your media type constants here
MediaType FOO = MediaType.parse("application/foo");

// Work out the file's type
MediaType type = detector.detect(stream, metadata);

// Is it one we want in the tree?
while (type != null && !type.equals(MediaType.OCTET_STREAM)) {
   if (type.equals(MediaType.Application_XML)) {
       doThingForXML();
   } else if (type.equals(MediaType.APPLICATION_ZIP)) { 
       doThingForZip();
   } else if (type.equals(FOO)) {
       doThingForFoo();
   } else {
       // Check parent
       type = registry.getSuperType(type);
   }
}