AnnotationProcessor      Annotation 处理的接口，实现类是DefaltAnnotationProcessor :

public class DefaultAnnotationProcessor implements AnnotationProcessor {
   
    protected javax.naming.Context context = null;
   
    public DefaultAnnotationProcessor(javax.naming.Context context) {
        this.context = context;
    }

    /**
     * Call postConstruct method on the specified instance.
     */
    public void postConstruct(Object instance)
        throws IllegalAccessException, InvocationTargetException {
       
        Method[] methods = instance.getClass().getDeclaredMethods();
        Method postConstruct = null;
        for (int i = 0; i < methods.length; i++) {
            if (methods[i].isAnnotationPresent(PostConstruct.class)) {
                if ((postConstruct != null)
                        || (methods[i].getParameterTypes().length != 0)
                        || (Modifier.isStatic(methods[i].getModifiers()))
                        || (methods[i].getExceptionTypes().length > 0)
                        || (!methods[i].getReturnType().getName().equals("void"))) {
                    throw new IllegalArgumentException("Invalid PostConstruct annotation");
                }
                postConstruct = methods[i];
            }
        }

        // At the end the postconstruct annotated
        // method is invoked
        if (postConstruct != null) {
            boolean accessibility = postConstruct.isAccessible();
            postConstruct.setAccessible(true);
            postConstruct.invoke(instance);
            postConstruct.setAccessible(accessibility);
        }
       
    }
   
   
    /**
     * Call preDestroy method on the specified instance.
     */
    public void preDestroy(Object instance)
        throws IllegalAccessException, InvocationTargetException {
       
        Method[] methods = instance.getClass().getDeclaredMethods();
        Method preDestroy = null;
        for (int i = 0; i < methods.length; i++) {
            if (methods[i].isAnnotationPresent(PreDestroy.class)) {
                if ((preDestroy != null)
                        || (methods[i].getParameterTypes().length != 0)
                        || (Modifier.isStatic(methods[i].getModifiers()))
                        || (methods[i].getExceptionTypes().length > 0)
                        || (!methods[i].getReturnType().getName().equals("void"))) {
                    throw new IllegalArgumentException("Invalid PreDestroy annotation");
                }
                preDestroy = methods[i];
            }
        }

        // At the end the postconstruct annotated
        // method is invoked
        if (preDestroy != null) {
            boolean accessibility = preDestroy.isAccessible();
            preDestroy.setAccessible(true);
            preDestroy.invoke(instance);
            preDestroy.setAccessible(accessibility);
        }
       
    }
   
   
    /**
     * Inject resources in specified instance.
     */
    public void processAnnotations(Object instance)
        throws IllegalAccessException, InvocationTargetException, NamingException {
       
        if (context == null) {
            // No resource injection
            return;
        }
       
        // Initialize fields annotations
        Field[] fields = instance.getClass().getDeclaredFields();
        for (int i = 0; i < fields.length; i++) {
            if (fields[i].isAnnotationPresent(Resource.class)) {
                Resource annotation = (Resource) fields[i].getAnnotation(Resource.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(EJB.class)) {
                EJB annotation = (EJB) fields[i].getAnnotation(EJB.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(WebServiceRef.class)) {
                WebServiceRef annotation =
                    (WebServiceRef) fields[i].getAnnotation(WebServiceRef.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(PersistenceContext.class)) {
                PersistenceContext annotation =
                    (PersistenceContext) fields[i].getAnnotation(PersistenceContext.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(PersistenceUnit.class)) {
                PersistenceUnit annotation =
                    (PersistenceUnit) fields[i].getAnnotation(PersistenceUnit.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
        }
       
        // Initialize methods annotations
        Method[] methods = instance.getClass().getDeclaredMethods();
        for (int i = 0; i < methods.length; i++) {
            if (methods[i].isAnnotationPresent(Resource.class)) {
                Resource annotation = (Resource) methods[i].getAnnotation(Resource.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(EJB.class)) {
                EJB annotation = (EJB) methods[i].getAnnotation(EJB.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(WebServiceRef.class)) {
                WebServiceRef annotation =
                    (WebServiceRef) methods[i].getAnnotation(WebServiceRef.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(PersistenceContext.class)) {
                PersistenceContext annotation =
                    (PersistenceContext) methods[i].getAnnotation(PersistenceContext.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(PersistenceUnit.class)) {
                PersistenceUnit annotation =
                    (PersistenceUnit) methods[i].getAnnotation(PersistenceUnit.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
        }

    }
   
   
    /**
     * Inject resources in specified field.
     */
    protected static void lookupFieldResource(javax.naming.Context context,
            Object instance, Field field, String name)
        throws NamingException, IllegalAccessException {
   
        Object lookedupResource = null;
        boolean accessibility = false;
       
        if ((name != null) &&
                (name.length() > 0)) {
            lookedupResource = context.lookup(name);
        } else {
            lookedupResource = context.lookup(instance.getClass().getName() + "/" + field.getName());
        }
       
        accessibility = field.isAccessible();
        field.setAccessible(true);
        field.set(instance, lookedupResource);
        field.setAccessible(accessibility);
    }

    /**
     * Inject resources in specified method.
     */
    protected static void lookupMethodResource(javax.naming.Context context,
            Object instance, Method method, String name)
        throws NamingException, IllegalAccessException, InvocationTargetException {
       
        if (!method.getName().startsWith("set")
                || method.getParameterTypes().length != 1
                || !method.getReturnType().getName().equals("void")) {
            throw new IllegalArgumentException("Invalid method resource injection annotation");
        }
       
        Object lookedupResource = null;
        boolean accessibility = false;
       
        if ((name != null) &&
                (name.length() > 0)) {
            lookedupResource = context.lookup(name);
        } else {
            lookedupResource =
                context.lookup(instance.getClass().getName() + "/" + method.getName().substring(3));
        }
       
        accessibility = method.isAccessible();
        method.setAccessible(true);
        method.invoke(instance, lookedupResource);
        method.setAccessible(accessibility);
    }
   

}