不能从在Tomcat的自定义类加载器加载的类注释 [英] Can't get annotations from classes loaded by custom classloader in tomcat
问题描述
由于类 org.popper.example.pages.Login
@Page(name="Login")
public interface Login {
}
出口 C:\\ POS \\ example.jar
及以下的servlet
exported to c:\pos\example.jar
and the following servlet
public class PopperServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public static void main(String[] args) throws MalformedURLException, ClassNotFoundException {
URLClassLoader ucl = new URLClassLoader(new URL[] {new File("c:/pos/example.jar").toURI().toURL()});
System.out.println(Arrays.asList(ucl.loadClass("org.popper.example.pages.Login").getAnnotations()));
}
public PopperServlet() throws MalformedURLException, ClassNotFoundException {
URLClassLoader ucl = new URLClassLoader(new URL[] {new File("c:/pos/example.jar").toURI().toURL()});
System.out.println(Arrays.asList(ucl.loadClass("org.popper.example.pages.Login").getAnnotations()));
}
}
运行code作为主要显示了预期的结果。
Running the code as main shows the expected result
[@org.popper.fw.annotations.Page(name=Login)]
运行code作为的servlet在Tomcat中没有找到注释
Running the code as servlet in tomcat doesn't find the annotations
[]
谁能告诉我,为什么?
Can anybody tell me why?
推荐答案
这是与往常一样!方面的类加载器层次结构
It's the same as always: Regard the classloader-hierarchy!
new URLClassLoader(new URL[] {new File("c:/pos/example.jar").toURI().toURL()}, PopperServlet.class.getClassloader());
做的伎俩。但令人惊讶的是注释都没有发现,而不是的ClassNotFoundException
或 NoClassDefError
,这就是我所期待的时候都没有发现注解加载类时...
did the trick. But it's surprising that annotations aren't found instead a ClassNotFoundException
or NoClassDefError
, thats what I expected when annotations are not found when loading a class...
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