新手学习笔记Spring AOP全自动编程

业务类

package oyb.service;

public interface IUserService {
    public void add();
    public void delete();
}

package oyb.service;

public class UserServiceImpl implements IUserService {
    @Override
    public void add() {
        System.out.println("添加用户。。。。");
    }

    @Override
    public void delete() {
        System.out.println("删除用户");
    }
}

切面类

package oyb.aspect;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

public class MyAspect implements MethodInterceptor{

    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
        return methodInvocation.proceed();
    }
}

Spring配置文件

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       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/context
                            http://www.springframework.org/schema/context/spring-context.xsd
                            http://www.springframework.org/schema/aop
                            http://www.springframework.org/schema/aop/spring-aop.xsd">

    <!--配置UserService-->
    <bean id="userService" class="oyb.service.UserServiceImpl"></bean>

    <!--默认情况下Spring的AOP生成的代理是JDK的Proxy实现的-->
    <!--配置切面对象-->
    <bean id="myAspect" class="oyb.aspect.MyAspect"></bean>

    <!--proxy-target-class为true表示开启cglib增强-->
    <aop:config proxy-target-class="true">

        <aop:pointcut id="myPointcut" expression="execution(* oyb.service.*.*(..))"></aop:pointcut>
        <!--通知 关联 切入点-->
        <aop:advisor advice-ref="myAspect" pointcut-ref="myPointcut"></aop:advisor>
    </aop:config>

</beans>

package oyb.test;


import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import oyb.service.IUserService;

public class test {

    @Test
    public void test(){
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");

        IUserService userService = (IUserService) context.getBean("userService");
        userService.add();

    }
}

测试结果：

之前一直抛出Bean named 'myAspect' must be of type [org.aopalliance.aop.Advice],这个异常，检查之后发现切面类MyAspect中没有实现MethodInterceptor接口，所以会报这个错误。

这个简单的案例当中，导入了com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar这个包

这里简单介绍一下AspectJ，AspectJ是一个基于Java语言的AOP框架，在Spring 2.0以后新增了对AspectJ切点表达式支持，在新版本的Spring当中，大部分都使用AspectJ的方式来进行开发。

 下面介绍一下AspectJ的几种通知类型

1.before:前置通知，主要应用到各种校验。在方法执行前执行，如果通知抛出异常，方法将进行不了。

2.afterReturning:后置通知，主要应用于常规数据处理。方法执行如果抛出异常，则也执行不了。在方法执行后执行，可以获得方法的返回值。

3.around：环绕通知，

4.afterThrowing:抛出异常通知,方法抛出异常时执行，否则无法执行

5.after:最终通知，方法执行完毕之后执行，无论是否抛出异常

例子：

1.导入相应的包(基于xml配置)：

2.业务类

package oyb.service;

public interface IUserService {
    public void add();
    public void delete();
    public void update();
}

package oyb.service.impl;

import oyb.service.IUserService;

public class UserServiceImpl implements IUserService {
    @Override
    public void add() {
        System.out.println("添加用户。。。");
    }

    @Override
    public void delete() {
        System.out.println("删除用户。。。");
    }

    @Override
    public void update() {
        System.out.println("更新用户。。。");
    }
}

3.切面类

package oyb.aspect;

import org.aspectj.lang.JoinPoint;

public class MyAspect {

    public void myBefore(JoinPoint joinPoint){
        System.out.println("前置通知");
    }
    public void myReturning(JoinPoint joinPoint){
        System.out.println("后置通知");
    }
}

配置文件

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       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/context
                            http://www.springframework.org/schema/context/spring-context.xsd
                            http://www.springframework.org/schema/aop
                            http://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="userService" class="oyb.service.impl.UserServiceImpl"></bean>

    <bean id="myAspect" class="oyb.aspect.MyAspect"></bean>

    <aop:config>
        <aop:aspect ref="myAspect">
            <aop:pointcut id="myPointcut" expression="execution(* oyb.service.impl.UserServiceImpl.*(..))"/>
            <!--前置通知-->
            <aop:before method="myBefore" pointcut-ref="myPointcut"></aop:before>
            <!--后置通知
           
            -->
            <aop:after-returning method="myReturning" pointcut-ref="myPointcut" ></aop:after-returning>
        </aop:aspect>
    </aop:config>

</beans>

测试类

package oyb.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import oyb.service.IUserService;

public class test {

    @Test
    public  void test(){

        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        IUserService userService = (IUserService) context.getBean("userService");
        userService.add();
    }
}

测试结果

 使用注解

Spring配置文件中

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       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/context
                            http://www.springframework.org/schema/context/spring-context.xsd
                            http://www.springframework.org/schema/aop
                            http://www.springframework.org/schema/aop/spring-aop.xsd">

    <context:component-scan base-package="oyb"></context:component-scan>

    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>



</beans>

业务类中添加注解如图

切面类

package oyb.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class MyAspect {

    //声明公共切入点
    @Pointcut("execution(* oyb.service.impl.UserServiceImpl.*(..))")
    public void myPointcut(){

    }
    @Before(value ="myPointcut()")
    public void myBefore(JoinPoint joinPoint){
        System.out.println("前置通知");
    }

    @AfterReturning(value = "myPointcut()")
    public void myReturning(JoinPoint joinPoint){

        System.out.println("后置通知");
    }
}

测试类

package oyb.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import oyb.service.IUserService;

public class test {

    @Test
    public  void test(){

        ApplicationContext context = new ClassPathXmlApplicationContext("beans2.xml");
        IUserService userService = (IUserService) context.getBean("userService");
        userService.add();
    }
}

测试结果如图：