Java 自定义注解与注解解析实例

package mydefineComponent;

import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.cglib.core.SpringNamingPolicy;
import org.springframework.cglib.proxy.Enhancer;

public class FactoryBeanTest<T> implements InitializingBean, FactoryBean<T> {
	
	private String innerClassName;
	
	public void setInnerClassName(String innerClassName) {
		this.innerClassName = innerClassName;
	}
	
	@Override
	public void afterPropertiesSet() throws Exception {
		// TODO Auto-generated method stub
		
	}

	@Override
	public T getObject() throws Exception {
		Class innerClass = Class.forName(innerClassName);
		if (innerClass.isInterface()) {
			return (T) InterfaceProxy.newInstance(innerClass);
		} else {
			Enhancer enhancer = new Enhancer();
			enhancer.setSuperclass(innerClass);
			enhancer.setNamingPolicy(SpringNamingPolicy.INSTANCE);
			enhancer.setCallback(new MethodInterceptorImpl());
			return (T) enhancer.create();
		}
	}
	

	@Override
	public Class<?> getObjectType() {
		try {
			return Class.forName(innerClassName);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		return null;
	}

	@Override
	public boolean isSingleton() {
		// TODO Auto-generated method stub
		return true;
	}
	
}

package mydefineComponent;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class InterfaceProxy implements InvocationHandler {
	

	@Override
	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		System.out.println("ObjectProxy execute:" + method.getName());
		return method.invoke(proxy, args);
	}
	
	public static <T> T newInstance(Class<T> innerInterface) {
		ClassLoader classLoader = innerInterface.getClassLoader();
		Class[] interfaces = new Class[] { innerInterface };
		InterfaceProxy proxy = new InterfaceProxy();
		return (T) Proxy.newProxyInstance(classLoader, interfaces, proxy);
	}
}

package mydefineComponent;

import java.lang.reflect.Method;

import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;

public class MethodInterceptorImpl implements MethodInterceptor{

	@Override
	public Object intercept(Object o, Method method, Object[] objects,
			MethodProxy methodProxy) throws Throwable {
		System.out.println("MethodInterceptorImpl:" + method.getName());
		return methodProxy.invokeSuper(o, objects);
	}
	
	

}

package mydefineComponent;

@MyDefineComponent
public class ScanClass1 {

	public void print() {
		System.out.print("scanclass1");
	}
}

package mydefineComponent;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MyDefineComponentTest {

	public static void main(String[] args) {
		 AnnotationConfigApplicationContext acc = new AnnotationConfigApplicationContext("mydefineComponent");
		 ScanClass1 scanClass = acc.getBean(ScanClass1.class);
		 scanClass.print();
	}

}

MethodInterceptorImpl:print
scanclass1

package com.my.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ ElementType.TYPE, ElementType.METHOD }) //可以用在方法或者类上面
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Fooish {
	
	String[] tags() default { "all" };
}

package com.my.annotation;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class MyFooishHandler implements ApplicationContextAware, InitializingBean{

    private ApplicationContext applicationContext;
    
	private List<String> allFooish = new ArrayList<>();

	@Override
	public void afterPropertiesSet() throws Exception {
		scanFooishClass();
        scanFooishMethod();
        System.out.println(allFooish);
		
	}

	/**
	 * 查找 用 Fooish 注解的 方法
	 */
	private void scanFooishMethod() throws Exception{
		final Map<String, Object> permissionMap = applicationContext.getBeansWithAnnotation(Fooish.class);
		System.out.println("this is permissionMap" + permissionMap.toString());
        for (final Object permissionObject : permissionMap.values()) {
            final Class<? extends Object> permissionClass = permissionObject.getClass();
            final Fooish annotation = permissionClass.getAnnotation(Fooish.class);
            if(annotation != null) {
                allFooish.addAll(Arrays.asList(annotation.tags()));
            }
        }


		
	}

	private void scanFooishClass() throws Exception{
		final Map<String, Object> controllerMap = applicationContext.getBeansWithAnnotation(Fooish.class);
        for (final Object controllerObject : controllerMap.values()) {
            final Class<? extends Object> controllerClass = controllerObject.getClass();
            for (Method method : controllerClass.getDeclaredMethods()) {
                Fooish fooish = method.getAnnotation(Fooish.class);
              if (fooish != null) {
                    allFooish.addAll(Arrays.asList(fooish.tags()));
                }
            }
        }

	}

	@Override
	public void setApplicationContext(ApplicationContext applicationContext)
			throws BeansException {
		 this.applicationContext = applicationContext;
		
	}

}

package com.my.controller;

import java.io.File;
import java.io.IOException;
import java.util.List;

import javax.annotation.Resource;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import com.my.annotation.Fooish;
import com.my.model.Student;
import com.my.service.FirstPageService;
import com.my.service.QRCodeUtil;

@RestController
@Fooish(tags={"this_is_class"})
public class FirstPageController {

	@Value(value = "${erweima.location:D:/Workspaces/MyEclipse 2015/entrance/src/main/resources/erweima.png}")
	private String imgPath;

	@Resource
	private FirstPageService firstPageService;

	@RequestMapping(value = "/", method = RequestMethod.GET)
	@Fooish(tags={"this_is_method"})
	String home() {
		return firstPageService.getString();
	}

	

}