package com.yiibai.customer.bo;

public interface CustomerBo {

	void addCustomer();
	
	String addCustomerReturnValue();
	
	void addCustomerThrowException() throws Exception;
	
	void addCustomerAround(String name);
}

package com.yiibai.customer.bo.impl;

import com.yiibai.customer.bo.CustomerBo;

public class CustomerBoImpl implements CustomerBo {

	public void addCustomer(){
		System.out.println("addCustomer() is running ");
	}
	
	public String addCustomerReturnValue(){
		System.out.println("addCustomerReturnValue() is running ");
		return "abc";
	}
	
	public void addCustomerThrowException() throws Exception {
		System.out.println("addCustomerThrowException() is running ");
		throw new Exception("Generic Error");
	}
	
	public void addCustomerAround(String name){
		System.out.println("addCustomerAround() is running, args : " + name);
	}
}

4. 啟用AspectJ

在 Spring 配置文件，把“<aop:aspectj-autoproxy />”，并定義Aspect(攔截)和普通的bean。

File : applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
	http://www.springframework.org/schema/aop 
	http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">

	<aop:aspectj-autoproxy />

	<bean id="customerBo" class="com.yiibai.customer.bo.impl.CustomerBoImpl" />

	<!-- Aspect -->
	<bean id="logAspect" class="com.yiibai.aspect.LoggingAspect" />

</beans>

4. AspectJ @Before

在下面例子中，logBefore()方法將在 customerBo接口的 addCustomer()方法的執(zhí)行之前被執(zhí)行。

AspectJ的“切入點(diǎn)”是用來(lái)聲明哪種方法將被攔截，應(yīng)該參考Spring AOP切入點(diǎn)指南，支持切入點(diǎn)表達(dá)式的完整列表。

File : LoggingAspect.java

package com.yiibai.aspect;

import org.aspectj.lang.JoinYiibai;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class LoggingAspect {

	@Before("execution(* com.yiibai.customer.bo.CustomerBo.addCustomer(..))")
	public void logBefore(JoinYiibai joinYiibai) {

		System.out.println("logBefore() is running!");
		System.out.println("hijacked : " + joinYiibai.getSignature().getName());
		System.out.println("******");
	}

}

運(yùn)行

CustomerBo customer = (CustomerBo) appContext.getBean("customerBo");
customer.addCustomer();

輸出結(jié)果

logBefore() is running!
hijacked : addCustomer
******
addCustomer() is running

5. AspectJ @After

在下面例子中，logAfter()方法將在 customerBo 接口的 addCustomer()方法的執(zhí)行之后執(zhí)行。

File : LoggingAspect.java

package com.yiibai.aspect;

import org.aspectj.lang.JoinYiibai;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.After;

@Aspect
public class LoggingAspect {

	@After("execution(* com.yiibai.customer.bo.CustomerBo.addCustomer(..))")
	public void logAfter(JoinYiibai joinYiibai) {

		System.out.println("logAfter() is running!");
		System.out.println("hijacked : " + joinYiibai.getSignature().getName());
		System.out.println("******");

	}

}

運(yùn)行它

CustomerBo customer = (CustomerBo) appContext.getBean("customerBo");
customer.addCustomer();

輸出結(jié)果

addCustomer() is running 
logAfter() is running!
hijacked : addCustomer
******

6. AspectJ @AfterReturning

在下面例子中，logAfterReturning()方法將在 customerBo 接口的addCustomerReturnValue()方法執(zhí)行之后執(zhí)行。此外，還可以截取返回的值使用“returning”屬性。

要截取返回的值，對(duì)“returning”屬性(結(jié)果)的值必須用相同的方法參數(shù)(結(jié)果)。

File : LoggingAspect.java

package com.yiibai.aspect;

import org.aspectj.lang.JoinYiibai;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.AfterReturning;

@Aspect
public class LoggingAspect {

   @AfterReturning(
      pointcut = "execution(* com.yiibai.customer.bo.CustomerBo.addCustomerReturnValue(..))",
      returning= "result")
   public void logAfterReturning(JoinYiibai joinYiibai, Object result) {

	System.out.println("logAfterReturning() is running!");
	System.out.println("hijacked : " + joinYiibai.getSignature().getName());
	System.out.println("Method returned value is : " + result);
	System.out.println("******");
   }
}

運(yùn)行它

CustomerBo customer = (CustomerBo) appContext.getBean("customerBo");
	customer.addCustomerReturnValue();

輸出結(jié)果

addCustomerReturnValue() is running 
logAfterReturning() is running!
hijacked : addCustomerReturnValue
Method returned value is : abc
******

7. AspectJ @AfterReturning

在下面的例子中，如果 customerBo 接口的addCustomerThrowException()方法拋出異常logAfterThrowing()方法將被執(zhí)行。

File : LoggingAspect.java

package com.yiibai.aspect;

import org.aspectj.lang.JoinYiibai;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.AfterThrowing;

@Aspect
public class LoggingAspect {

   @AfterThrowing(
      pointcut = "execution(* com.yiibai.customer.bo.CustomerBo.addCustomerThrowException(..))",
      throwing= "error")
    public void logAfterThrowing(JoinYiibai joinYiibai, Throwable error) {

	System.out.println("logAfterThrowing() is running!");
	System.out.println("hijacked : " + joinYiibai.getSignature().getName());
	System.out.println("Exception : " + error);
	System.out.println("******");

    }
}

運(yùn)行它

CustomerBo customer = (CustomerBo) appContext.getBean("customerBo");
customer.addCustomerThrowException();

輸出結(jié)果

addCustomerThrowException() is running 
logAfterThrowing() is running!
hijacked : addCustomerThrowException
Exception : java.lang.Exception: Generic Error
******
Exception in thread "main" java.lang.Exception: Generic Error
	//...

8. AspectJ @Around

在下面例子中，logAround()方法將在customerBo接口的addCustomerAround()方法執(zhí)行之前執(zhí)行，必須定義“joinYiibai.proceed();” 控制何時(shí)攔截器返回控制到原來(lái)的addCustomerAround()方法。

File : LoggingAspect.java

package com.yiibai.aspect;

import org.aspectj.lang.ProceedingJoinYiibai;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Around;

@Aspect
public class LoggingAspect {

   @Around("execution(* com.yiibai.customer.bo.CustomerBo.addCustomerAround(..))")
   public void logAround(ProceedingJoinYiibai joinYiibai) throws Throwable {

	System.out.println("logAround() is running!");
	System.out.println("hijacked method : " + joinYiibai.getSignature().getName());
	System.out.println("hijacked arguments : " + Arrays.toString(joinYiibai.getArgs()));
		
	System.out.println("Around before is running!");
	joinYiibai.proceed(); //continue on the intercepted method
	System.out.println("Around after is running!");
		
	System.out.println("******");

   }
	
}

運(yùn)行它

CustomerBo customer = (CustomerBo) appContext.getBean("customerBo");
customer.addCustomerAround("yiibai");

輸出結(jié)果

logAround() is running!
hijacked method : addCustomerAround
hijacked arguments : [yiibai]
Around before is running!
addCustomerAround() is running, args : yiibai
Around after is running!
******

總結(jié)

它總是建議采用最少 AspectJ 注解。這是關(guān)于Spring AspectJ 的一篇相當(dāng)長(zhǎng)的文章。進(jìn)一步的解釋和例子，請(qǐng)?jiān)L問(wèn)下面的參考鏈接。

下載源代碼 – http://pan.baidu.com/s/1boo4f9P

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