Spring学习笔记（三）

Spring学习笔记（三）

AOP

一、使用Annotation方式实现AOP。步骤：

1. xml里加入配置：<aop:aspectj-autoproxy />

   <?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"
       xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       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
               http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
       
       <context:annotation-config />
       <context:component-scan base-package="com.wangj.spring" />
       <aop:aspectj-autoproxy />
       
   </beans>

2. 再引入如下jar包:(注意：必须引入第三个jar)
3. @Aspect注解这个类
4. @Before @After等来注解方法
5. 写明切入点（execution(...)）
6. 将拦截器类交给Spring管理（@Component注解这个类）

   @Aspect
   @Component
   public class LogInterceptor {
       @Before("execution(public void com.wangj.spring.dao.impl.UserDaoImpl.save(com.wangj.spring.model.User))")
       public void before() {
           System.out.println("method before");
       }
       
       @After("execution(public void com.wangj.spring.dao.impl.UserDaoImpl.save(com.wangj.spring.model.User))")
       public void after() {
           System.out.println("method after(finally)");
       }
   }

二、织入点语法

execution(public * *(..)) // 作用于任何类任何方法
execution(* set*(..)) // 作用于任何以set开头的方法
execution(* com.wangj.spring.dao.impl.UserDaoImpl.*(..)) //作用于UserDaoImpl类的所有方法
execution(* com.wangj.spring.dao..*.*(..)) //作用于com.wangj.spring.dao包（包括所有子包）里的所有类的所有方法
execution(public void com.wangj.spring.dao.impl.UserDaoImpl.save(com.wangj.spring.model.User)) // 作用于UserDaoImpl类的save(User)方法

三、Annotation详解

　　1. @Pointcut 织入点集合

@Aspect
@Component
public class LogInterceptor {
    @Pointcut("execution(* com.wangj.spring.dao..*.*(..))")
    public void pointcutMethod() {}
    
//    @Before("execution(public void com.wangj.spring.dao.impl.UserDaoImpl.save(com.wangj.spring.model.User))")
    @Before("pointcutMethod()")
    public void before() {
        System.out.println("method before");
    }
    
//    @After("execution(public void com.wangj.spring.dao.impl.UserDaoImpl.save(com.wangj.spring.model.User))")
    @After("pointcutMethod()")
    public void after() {
        System.out.println("method after(finally)");
    }
}

　　2. @Before @After @AfterReturning @AfterThrowing @Around

@Aspect
@Component
public class LogInterceptor {
    @Pointcut("execution(* com.wangj.spring.dao..*.*(..))")
    public void pointcutMethod() {}
    
//    @Before("execution(public void com.wangj.spring.dao.impl.UserDaoImpl.save(com.wangj.spring.model.User))")
    @Before("pointcutMethod()")
    public void before() {
        System.out.println("method before");
    }
    
//    @After("execution(public void com.wangj.spring.dao.impl.UserDaoImpl.save(com.wangj.spring.model.User))")
    @After("pointcutMethod()") // 方法执行完切入即使方法产生了异常
    public void after() {
        System.out.println("method after(finally)");
    }
    
    @AfterReturning("pointcutMethod()") // 方法正常执行完后切入
    public void afterReturning() {
        System.out.println("method afterReturning");
    }
    
    @AfterThrowing("pointcutMethod()") // 方法抛出异常时切入
    public void afterThrowing() {
        System.out.println("method afterThrowing");
    }
    
    @Around("myMethod()") // 环绕即在方法前、后都可以加逻辑
    public void aroundMethod(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("method around start");
        pjp.proceed();
        System.out.println("method around end");
    }
}

四、使用XML方式实现AOP

<?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"
    xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:tx="http://www.springframework.org/schema/tx"
    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
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
    
    <context:annotation-config />
    <context:component-scan base-package="com.wangj.spring" />
    <!-- <aop:aspectj-autoproxy /> -->
    
    <bean id="logInterceptor" class="com.wangj.spring.aop.LogInterceptor2"></bean>
    
    <aop:config>
        <aop:pointcut id="daoPointcut" expression="execution(public * com.wangj.spring.dao..*.*(..)))"></aop:pointcut>
        <aop:aspect id="logAspect" ref="logInterceptor">
            <!-- <aop:before method="before" pointcut="execution(public * com.wangj.spring.dao..*.*(..))" /> --> <!-- 不使用全局pointcut -->
            <aop:before method="before" pointcut-ref="daoPointcut" />
            <aop:after method="after" pointcut-ref="daoPointcut" />
            <aop:after-returning method="afterReturning" pointcut-ref="daoPointcut" />
            <aop:after-throwing method="afterThrowing" pointcut-ref="daoPointcut"/>
            <aop:around method="aroundMethod" pointcut-ref="daoPointcut"/>
        </aop:aspect>
    </aop:config>
    
</beans>