Spring aspect 两种方式实现五种增强

    我们都知道spring中AOP（面向切面编程）支持多种增强类型，使之我们能更注重核心业务，而那些交叉业务（切面）则由增强来处理，我们来看一下配置增强的两种方式：注解和XML

注解：

1.引入jar包（上传图片不能用，只能粘贴了）

aopalliance.jar

com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar

commons-logging-1.2.jar

log4j-1.2.16.jar

spring-aop-4.2.0.RELEASE.jar

spring-aspects-4.2.0.RELEASE.jar

spring-beans-4.2.0.RELEASE.jar

spring-context-4.2.0.RELEASE.jar

spring-core-4.2.0.RELEASE.jar

spring-expression-4.2.0.RELEASE.jar

spring-test-4.2.0.RELEASE.jar

2.cn.aop---MyAspect.java(我们可以注释其他一个个测，因为抛出异常增强需要在UserdaoImpl.java中构建一个错误) 

package cn.aop;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class MyAspect {
    //前置
@Before("execution(public * *(..))")//execution(public * *(..))所有方法增强
public void beforeAspect(){
    
    System.out.println("前置增强");
}

//后置
@AfterReturning("execution(public * *(..))")
public void AfterReturningAspect(){
    
    System.out.println("后置增强");
}

//环绕
/*@Around("execution(public * *(..))")
public void AroundAspect(ProceedingJoinPoint po){
    
    System.out.println("环绕前增强");
    try {
        po.proceed();
    } catch (Throwable e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    System.out.println("环绕后增强");
}*/

//异常
@AfterThrowing("execution(public * *(..))")
public void AfterThrowingAspect(){
    
    System.out.println("异常增强");
}

//最终
@After("execution(public * *(..))")
public void AfterAspect(){
    
    System.out.println("最终增强");
}
}

3.cn.entity--Userdao.java

package cn.entity;

public interface Userdao {
public void dofirst();
public void dosecond();
}

4.cn.entity--UserdaoImpl.java

package cn.entity;

public class UserDaoImpl implements Userdao{

    @Override
    public void dofirst() {
        // TODO Auto-generated method stub
        System.out.println("例子一");
    }

    @Override
    public void dosecond() {
        // TODO Auto-generated method stub
        System.out.println("例子二");
    }

}

5.cn.test--ASpectTest.java

package cn.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import cn.entity.Userdao;

public class ASpectTest {
@Test
public void AspectTestBefore(){
     ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
      Userdao dao = (Userdao)context.getBean("daoimpl");
      dao.dofirst();
      dao.dosecond();
      
    
 }
}

6.applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd
     http://www.springframework.org/schema/aop
         http://www.springframework.org/schema/aop/spring-aop-4.1.xsd">
 <!-- 目标对象-->
   <bean id="daoimpl" class="cn.entity.UserDaoImpl"></bean>
   <!-- 增强 -->
   <bean class="cn.aop.MyAspect"></bean>
   <aop:aspectj-autoproxy/>
    </beans>
    

XML:（）

其他不变，cn.aop---MyAspect.java这个类改为（注解去掉，变为普通类）：

package cn.aop;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class MyAspect {
    //前置

public void beforeAspect(){
    
    System.out.println("前置增强");
}

//后置

public void AfterReturningAspect(){
    
    System.out.println("后置增强");
}


public void AroundAspect(ProceedingJoinPoint po){
    
    System.out.println("环绕前增强");
    try {
        po.proceed();
    } catch (Throwable e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    System.out.println("环绕后增强");
}

//异常

public void AfterThrowingAspect(){
    
    System.out.println("异常增强");
}

//最终

public void AfterAspect(){
    
    System.out.println("最终增强");
}
}

applicationContext.xml改变配置

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd
     http://www.springframework.org/schema/aop
         http://www.springframework.org/schema/aop/spring-aop-4.1.xsd">
 <!-- 目标对象-->
   <bean id="daoimpl" class="cn.entity.UserDaoImpl"></bean>
   <!-- 增强 -->
   <bean id="aspectAdvice" class="cn.aop.MyAspect"></bean>
  <aop:config>
    
     <aop:pointcut expression="execution(public * *(..))" id="allpointcut"/>
    <aop:aspect ref="aspectAdvice">
    <!-- 前置 -->
      <aop:before method="beforeAspect" pointcut-ref="allpointcut"/>
      <!-- 后置 -->
      <aop:after-returning method="AfterReturningAspect" pointcut-ref="allpointcut"/>
      <!-- 环绕 -->
      <aop:around method="AroundAspect" pointcut-ref="allpointcut"/>
      <!-- 异常抛出 -->
      <aop:after-throwing method="AfterThrowingAspect" pointcut-ref="allpointcut"/>
      <!-- 最终增强 -->
      <aop:after method="AfterAspect" pointcut-ref="allpointcut"/>
      
    </aop:aspect>
  </aop:config>
    </beans>
    

   今天就到这里！！！