Spring基于注解@AspectJ的AOP

Spring除了支持XML方式配置AOP，还支持注解方式：使用@AspectJ风格的切面声明。

但是用注解方式需要在XML启用对@AspectJ的支持<aop:aspectj-autoproxy/>，将在Spring上下文创建一个AnnotationAwareAspectJAutoProxyCreator类，它会自动代理一些Bean，这些Bean的方法需要与使用@Aspect注解的Bena中所定义的切点相匹配，而这些切点又是使用@Pointcut注解定义出来的，下面来看下例子(PS:我的例子都没有携带参数)：

前置通知：使用org.aspectj.lang.annotation 包下的@Before注解声明；
@Before(value = "切入点表达式或命名切入点", argNames = "参数列表参数名")
后置返回通知：使用org.aspectj.lang.annotation 包下的@AfterReturning注解声明；
@AfterReturning(  
value="切入点表达式或命名切入点",  
pointcut="切入点表达式或命名切入点",  
argNames="参数列表参数名",  
returning="返回值对应参数名")

后置最终通知：使用org.aspectj.lang.annotation 包下的@After注解声明；
@After (  
value="切入点表达式或命名切入点",  
argNames="参数列表参数名")

package cn.com.ztz.spring.service;  
  
public interface ShowService {  
    public void show();  
} 

package cn.com.ztz.spring.service;  
  
public class ShowServiceImpl implements ShowService{  
    @Override  
    public void show() {    
        showBefore();  
        //showError();//异常测试  
        showEnd();  
    }  
    public void showBefore(){  
        System.out.println("showBefore============");  
    }  
    public void showError(){  
        System.out.println("showError============");  
        throw new RuntimeException();  
    }  
    public void showEnd(){  
        System.out.println("showEnd===============");  
    }  
}

package cn.com.ztz.spring.service;

import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;

@Aspect
public class AudienceAspect {
	//定义切点
	@Pointcut("execution(* cn.com.ztz.spring.service.ShowServiceImpl.show(..))")
	public void performance(){
		//该方法的内容不重要，该方法的本身只是个标识，供@Pointcut注解依附
	}
	//前置通知
	@Before("performance()")
	public void taskSeats(){  
        System.out.println("等候节目开始===");  
    }  
	//后置通知
	@After("performance()")
    public void applaud(){  
        System.out.println("鼓掌=========");  
    }
	//后置异常通知
	@AfterThrowing("performance()")
    public void demandRefund(){  
        System.out.println("退钱离场======");  
    }  
}

<!-- 启用@AspectJ支持 -->
	<aop:aspectj-autoproxy/>
	<bean id="show" class="cn.com.ztz.spring.service.ShowServiceImpl"/>
	<bean id="audienceAspect" class="cn.com.ztz.spring.service.AudienceAspect"/>

public static void main(String[] args) {
		ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");    
        ShowService hs = ctx.getBean("show", ShowService.class);    
        System.out.println("======================================");  
        hs.show(); 
        System.out.println("======================================"); 
	}

======================================
等候节目开始===
showBefore============
showEnd===============
鼓掌=========
======================================

注解环绕通知

像Spring基于XML的AOP一样，@AspectJ注解的使用不仅只限定与定义前置和后置通知类型。我们还可以创建环绕通知，使用环绕通知需要使用@Around。

@Around (  
value="切入点表达式或命名切入点",  
argNames="参数列表参数名")

public interface ShowService {  
    public void show(String param);  
}

@Override  
    public void show(String param) {
    	System.out.println("around==========="+param); 
    } 

@Aspect
public class AudienceAspect {
	//定义切点
	@Pointcut("execution(* cn.com.ztz.spring.service.ShowServiceImpl.show(..))")
	public void performance(){
		//该方法的内容不重要，该方法的本身只是个标识，供@Pointcut注解依附
	}
	@Around("performance()")
	public Object aroundAdvice(ProceedingJoinPoint pjp) throws Throwable {    
        System.out.println("around before advice===========");    
        Object retVal = pjp.proceed(new Object[] {"around"});    
        System.out.println("around after advice===========");    
        return retVal;   
    }
}

======================================
around before advice===========
around===========around
around after advice===========
======================================

引入
@AspectJ风格的引入声明在切面中使用org.aspectj.lang.annotation包下的@DeclareParents声明

@DeclareParents(  
value="AspectJ语法类型表达式",  
defaultImpl="引入接口的默认实现类")  

package cn.com.ztz.spring.service;

public interface DeclareService {  
    public void declare();  
}

package cn.com.ztz.spring.service;
public class DeclareServiceImpl implements DeclareService {  
    @Override  
    public void declare() {  
        System.out.println("declare=====================");  
    }  
} 

package cn.com.ztz.spring.service;

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.DeclareParents;

@Aspect
public class AudienceAspect {
	@DeclareParents(value="cn.com.ztz.spring.service.ShowServiceImpl+",
			defaultImpl=cn.com.ztz.spring.service.DeclareServiceImpl.class)
	private DeclareService declareService;}

public static void main(String[] args) {
		ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");    
		DeclareService hs = ctx.getBean("show", DeclareService.class);    
        System.out.println("======================================");  
        hs.declare(); 
        System.out.println("======================================"); 
	}

======================================
declare=====================
======================================

Spring基于注解@AspectJ的AOP

原文：http://blog.csdn.net/luckey_zh/article/details/46780165