找到和运行私有注释方法的最简单方法是什么？

Question

import org.apache.commons.lang3.reflect.MethodUtils;

import javax.annotation.PostConstruct;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Created by dims on 13.10.2016.
 */
public class CallPrivateMethodTest {

   @Retention(RUNTIME)
   @Target(METHOD)
   public @interface MyAnnotation {
   }

   public static class MyClass {

      @MyAnnotation
      private void myMethod() {
         System.out.println("myMethod() ran");
      }
   }

   public static void main(String[] args) {

      MyClass myObject = new MyClass();

      List<Method> methods = MethodUtils.getMethodsListWithAnnotation(myObject.getClass(), MyAnnotation.class);


      for(int i=0; i<methods.size(); ++i) {
         try {
            methods.get(i).invoke(myObject);
         } catch (IllegalAccessException e) {
            e.printStackTrace();
         } catch (InvocationTargetException e) {
            e.printStackTrace();
         }
      }
   }
}

Answer 1

必须对方法调用setAccessible(true)。

请参见AccessibleObject的Javadoc，它是方法的超类型。

在您的示例中：

methods.get(i).setAccessible(true);
methods.get(i).invoke(myObject);

MyClass myObject = new MyClass ();

Method[] allMethods = myObject.getClass ().getDeclaredMethods ();
List<Method> annotatedMethods = Arrays.stream (allMethods)
                                      .filter (m -> m.getAnnotation (MyAnnotation.class) != null)
                                      .collect (Collectors.toList ());

for (Method method: annotatedMethods) {
  try {
    method.setAccessible (true);
    method.invoke (myObject);
  } catch (IllegalAccessException e) {
    e.printStackTrace ();
  } catch (InvocationTargetException e) {
    e.printStackTrace ();
  }
}