Spring教程

Spring初学快速入门
安装Spring工具套件到Eclipse
Spring快速入门
- Spring hello world实例
- Spring松耦合实例
Spring自动装配Bean
Spring JDBC支持
Spring JavaConfig
- Spring JavaConfig实例
- Spring JavaConfig @Import实例
Spring 依赖注入(DI)
Spring Bean基础
Spring表达式语言
Spring自动组件扫描
- Spring自动扫描组件
- Spring过滤器组件自动扫描
Spring AOP (面向方面编程)
Spring AOP + AspectJ框架
- Spring AOP+AspectJ注解实例
- Spring AOP+AspectJ在XML配置实例
Spring Hibernate支持
Spring E-mail支持
Spring与其它Web框架集成

Spring AOP+AspectJ注解实例

在本教程中，我们将向你展示如何将AspectJ注解集成到Spring AOP框架。在这个Spring AOP+ AspectJ 示例中，让您轻松实现拦截方法。

常见AspectJ的注解：

@Before – 方法执行前运行
@After – 运行在方法返回结果后
@AfterReturning – 运行在方法返回一个结果后，在拦截器返回结果。
@AfterThrowing – 运行方法在抛出异常后，
@Around – 围绕方法执行运行，结合以上这三个通知。

注意

Spring AOP 中没有 AspectJ 支持，请阅读内置 Spring AOP 例子。

1. 目录结构

看到这个例子的目录结构。

2. Spring Beans

普通 bean 中有几个方法，后来通过 AspectJ 注解拦截。

package com.zyiz.customer.bo;

public interface CustomerBo {

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

package com.zyiz.customer.bo.impl;

import com.zyiz.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. 启用AspectJ

在 Spring 配置文件，把“<aop:aspectj-autoproxy />”，并定义Aspect(拦截)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.zyiz.customer.bo.impl.CustomerBoImpl" />

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

</beans>

4. AspectJ @Before

在下面例子中，logBefore()方法将在 customerBo接口的 addCustomer()方法的执行之前被执行。

AspectJ的“切入点”是用来声明哪种方法将被拦截，应该参考Spring AOP切入点指南，支持切入点表达式的完整列表。

File : LoggingAspect.java

package com.zyiz.aspect;

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

@Aspect
public class LoggingAspect {

	@Before("execution(* com.zyiz.customer.bo.CustomerBo.addCustomer(..))")
	public void logBefore(Joinzyiz joinzyiz) {

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

}

运行

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

输出结果

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

5. AspectJ @After

在下面例子中，logAfter()方法将在 customerBo 接口的 addCustomer()方法的执行之后执行。

File : LoggingAspect.java

package com.zyiz.aspect;

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

@Aspect
public class LoggingAspect {

	@After("execution(* com.zyiz.customer.bo.CustomerBo.addCustomer(..))")
	public void logAfter(Joinzyiz joinzyiz) {

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

	}

}

运行它

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

输出结果

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

6. AspectJ @AfterReturning

在下面例子中，logAfterReturning()方法将在 customerBo 接口的addCustomerReturnValue()方法执行之后执行。此外，还可以截取返回的值使用“returning”属性。

要截取返回的值，对“returning”属性(结果)的值必须用相同的方法参数(结果)。

File : LoggingAspect.java

package com.zyiz.aspect;

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

@Aspect
public class LoggingAspect {

   @AfterReturning(
      pointcut = "execution(* com.zyiz.customer.bo.CustomerBo.addCustomerReturnValue(..))",
      returning= "result")
   public void logAfterReturning(Joinzyiz joinzyiz, Object result) {

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

运行它

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

输出结果

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()方法抛出异常logAfterThrowing()方法将被执行。

File : LoggingAspect.java

package com.zyiz.aspect;

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

@Aspect
public class LoggingAspect {

   @AfterThrowing(
      pointcut = "execution(* com.zyiz.customer.bo.CustomerBo.addCustomerThrowException(..))",
      throwing= "error")
    public void logAfterThrowing(Joinzyiz joinzyiz, Throwable error) {

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

    }
}

运行它

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

输出结果

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()方法将在customerBo接口的addCustomerAround()方法执行之前执行，必须定义“joinzyiz.proceed();” 控制何时拦截器返回控制到原来的addCustomerAround()方法。

File : LoggingAspect.java

package com.zyiz.aspect;

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

@Aspect
public class LoggingAspect {

   @Around("execution(* com.zyiz.customer.bo.CustomerBo.addCustomerAround(..))")
   public void logAround(ProceedingJoinzyiz joinzyiz) throws Throwable {

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

   }
	
}

运行它

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

输出结果

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

总结

它总是建议采用最少 AspectJ 注解。这是关于Spring AspectJ 的一篇相当长的文章。进一步的解释和例子，请访问下面的参考链接。

下载源代码 – http://pan.baidu.com/s/1boo4f9P

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