Spring07：AOP

AOP：面向切面编程

Aop 在 不改变原有代码的情况下 , 去增加新的功能

通过 Spring API 实现AOP

<dependencies>
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.9.4</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>5.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.1</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.1</version>
    </dependency>
</dependencies>

public interface UserService {

    public void add();
    public void delete();
    public void update();
    public void search();

}

目标业务类

public class UserServiceImpl implements UserService{

    public void add() {
        System.out.println("增加用户");
    }

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

    public void update() {
        System.out.println("修改用户");
    }

    public void search() {
        System.out.println("查询用户");
    }
}

public class Log implements MethodBeforeAdvice {
    //method : 要执行的目标对象的方法
    //objects : 被调用的方法的参数
    //Object : 目标对象
    public void before(Method method, Object[] objects, Object o) throws Throwable {
        System.out.println(o.getClass().getName()+"的"+method.getName()+"方法被执行了");
    }
}

public class AfterLog implements AfterReturningAdvice {
    //returnValue 返回值
    //method被调用的方法
    //args 被调用的方法的对象的参数
    //target 被调用的目标对象
    public void afterReturning(Object returnValue, Method method, Object[] objects, Object target) throws Throwable {
        System.out.println("执行了"+target.getClass().getName()+"的"+method.getName()+"方法，返回值："+returnValue);
    }
}

beans.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.xsd">

    <!--注册bean-->
    <bean id="userService" class="com.wgg.service.UserServiceImpl"/>
    <bean id="log" class="com.wgg.log.Log"/>
    <bean id="afterLog" class="com.wgg.log.AfterLog"/>

    <!--aop的配置-->
    <aop:config>
        <!--切入点，*后跟空格-->
        <aop:pointcut id="pointcut" expression="execution(* com.wgg.service.UserServiceImpl.*(..))"/>

        <!--切入点执行-->
        <aop:advisor advice-ref="log" pointcut-ref="pointcut"/>
        <aop:advisor advice-ref="afterLog" pointcut-ref="pointcut"/>
    </aop:config>
</beans>

测试

public class MyTest {
    @Test
    public void test(){
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        UserService userService = (UserService) context.getBean("userService");
        userService.update();
    }
}

自定义类来实现Aop

自定义切入类

public class DiyPointcut {

    public void before(){
        System.out.println("----------方法执行前---------------");
    }

    public void after(){
        System.out.println("-----------方法执行后----------------");
    }
}

<!--注册bean-->
<bean id="userService" class="com.wgg.service.UserServiceImpl"/>
<bean id="diy" class="com.wgg.config.DiyPointcut"/>

<!--aop的配置-->
<aop:config>
    <aop:aspect ref="diy">
        <aop:pointcut id="diyPointcut" expression="execution(* com.wgg.service.UserServiceImpl.*(..))"/>
        <aop:before pointcut-ref="diyPointcut" method="before"/>
        <aop:after pointcut-ref="diyPointcut" method="after"/>
    </aop:aspect>

</aop:config>

测试

public class MyTest {
    @Test
    public void test(){
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        UserService userService = (UserService) context.getBean("userService");
        userService.add();
    }
}

使用注解实现

使用注解实现的增强类

@Aspect
public class AnnotationPointcut {
    @Before("execution(* com.wgg.service.UserServiceImpl.*(..))")
    public void before(){
        System.out.println("-------方法执行前-----------");
    }

    @After("execution(* com.wgg.service.UserServiceImpl.*(..))")
    public void after(){
        System.out.println("-----------方法执行后-----------");
    }

    @Around("execution(* com.wgg.service.UserServiceImpl.*(..))")
    public void around(ProceedingJoinPoint jp) throws Throwable {
        System.out.println("环绕前");
        System.out.println("签名："+jp.getSignature());

        //执行目标方法
        Object proceed = jp.proceed();
        System.out.println("环绕后");
        System.out.println(proceed);
    }
}

注册bean，添加注解支持

<bean id="userService" class="com.wgg.service.UserServiceImpl"/>
<bean id="annotationPointcut" class="com.wgg.config.AnnotationPointcut"/>
<aop:aspectj-autoproxy/>

测试

@Test
public void test(){
    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
    UserService userService = (UserService) context.getBean("userService");
    userService.add();
}