JdkDynamicAopProxy

[ovidiusnassos]

Hi,

I have obtained a JdkDynamicAopProxy.
I need to invoke a method from target class via reflection.
I now only method name and parameters, i don't have a "Method object".

How can i do this?

Best regards.

[denis.zhdanov]

Reflection tutorial

Btw, I don't think that it's really necessary to get JdkDynamicAopProxy object and explicitly call a method on it.

[ovidiusnassos]

I obtained this JdkDynamicAopProxy from the bean container.
The target class have @Secured annotation and the bean injected is JdkDynamicAopProxy.

[al0]

Ok, but it does not explain why you need to use reflection. Did I miss something?

I obtained this JdkDynamicAopProxy from the bean container.
The target class have @Secured annotation and the bean injected is JdkDynamicAopProxy.

[jamestastic]

What is it that you're trying to do with the JdkDynamicAopProxy? If you simply want to invoke a method via reflection, you don't need anything Spring-specific. Here's an example:

		MyClass myClass = new MyClass();
		Method method = myClass.getClass().getMethod("printHelloWorld");
		method.invoke(myClass);

Here, MyClass is a class that implements a public void printHelloWorld() {}

[Ovidiu Ariton]

I have a generic mapping class where i decide what method to call and the target spring bean based on my business logic.

At this point i now the method name who have a generic signature and the spring bean.

When i want to invoke the method i have a proxy to the bean, not the bean itself.

Object bean = ctx.getBean("myBean");
Class c = AopUtils.getTargetClass(bean);
Method m = c.getMethod(methodName, new Class[] { Param1.class, Param2.class });
Object obj =AopUtils.invokeJoinpointUsingReflection(contrlooe r, m, new Object[] { param1Instance, param2Instance });

At this point i receive this error:

Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoi npointUsingReflection(AopUtils.java:307)
... 30 more

My target class have a @Secured annotation.

What i am doing wrong?

[al0]

1. Is method that you are trying to call a member of some interface implemented by your class? If so then you need not go for target class - just call it directly on the proxy. If not - then it is the most likely severe design error. Rethink your solution once more.
2. From your snippet is absolutely unclear what is "contrlooe r", how you have obtained it and if it has something in common with your target object.
3. And to reach your object you may do something like this (as created proxy likely to be instansce of Advised)
   

       static public <T> T getUltimateTarget(T target) {
           while (target != null && target instanceof Advised)
               try {
                   target = (T) ((Advised) target).getTargetSource().getTarget();
               } catch (Exception e) {
                   ... Do something or rethros
               }
           return target;
       }

4. And BTW, why you fetch bean from context by name - with some relatively rare exceptions it smells

I have a generic mapping class where i decide what method to call and the target spring bean based on my business logic.

At this point i now the method name who have a generic signature and the spring bean.

When i want to invoke the method i have a proxy to the bean, not the bean itself.

Object bean = ctx.getBean("myBean");
Class c = AopUtils.getTargetClass(bean);
Method m = c.getMethod(methodName, new Class[] { Param1.class, Param2.class });
Object obj =AopUtils.invokeJoinpointUsingReflection(contrlooe r, m, new Object[] { param1Instance, param2Instance });

At this point i receive this error:

Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoi npointUsingReflection(AopUtils.java:307)
... 30 more

My target class have a @Secured annotation.

What i am doing wrong?

[Ovidiu Ariton]

1. I declared an interface and i make my class implement that interface (correct design)
2. "controller" is the proxy object obtained from spring container
4. i corrected my code

I resolve the problem by obtaining the "method" object from the interface implemented by my class, not from the class.

Thanks for responses.

Best regards.