AspectJ主要使用注解的方式来实现AOP,Spring AOP偏重编程的方式

1.示例接口

public interface Waiter {
   void greetTo(String name);
   void serveTo(String name);
}

public class NaiveWaiter implements Waiter {
    public void greetTo(String name) {
        System.out.println("greet to "+name+"...");
    }
    public void serveTo(String name){
        System.out.println("serving "+name+"...");
    }
}

2.定义切面

2.1 使用Aspect注解定义一个切面
2.2 Before表示增强类型中的前置增强
2.3 execution表示切点表达式

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

@Aspect
public class PreGreetingAspect{
    @Before("execution(* greetTo(..))")
    public void beforeGreeting(){
        System.out.println("How are you");
    }
}

3.生成切面代理

3.1 使用AspectJProxyFactory

即编程模式

    @Test
    public void proxy(){
        Waiter target = new NaiveWaiter();
        AspectJProxyFactory factory = new AspectJProxyFactory();
        factory.setTarget(target);
        factory.addAspect(PreGreetingAspect.class);
        Waiter proxy = factory.getProxy();
        proxy.greetTo("John");
        proxy.serveTo("John");
    }

输出结果:

How are you
greet to John...
serving John...

3.2 xml模式

aop:aspectj-autoproxy是AnnotationAwareAspectJAutoProxyCreator的简约模式

    <aop:aspectj-autoproxy/>
    <!--bean class="org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator"/-->
    <bean id="waiter" class="aop.smart.advice.NaiveWaiter" />
    <bean class="aop.smart.aspectj.example.PreGreetingAspect" />

3.2 注解模式(EnableAspectJAutoProxy)

@Configuration
@EnableAspectJAutoProxy
public class AspectJConfig {

    @Bean("waiter")
    public Waiter getWaiter()
    {
        return new NaiveWaiter();
    }

    @Bean
    public PreGreetingAspect getPreGreetingAspect()
    {
        return new PreGreetingAspect();
    }
}

4.增强类型

修改

    public void serveTo(String name){
        System.out.println("serving "+name+"...");

        throw new RuntimeException();
    }

@Aspect
public class TestGreetingAspect {

    @Before("execution(* greetTo(..))")
    public void beforeGreeting(){
        System.out.println("beforeGreeting");
    }

    @AfterReturning("execution(* greetTo(..))")
    public void afterReturningGreeting(){
        System.out.println("afterReturningGreeting");
    }

    @Around("execution(* greetTo(..))")
    public void aroudGreeting(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("before aroudGreeting before");
        pjp.proceed();
        System.out.println("after aroudGreeting");
    }

    @AfterThrowing("execution(* serveTo(..))")
    public void afterThrowingGreeting() throws Throwable {
        System.out.println("afterThrowingGreeting");
    }

    @After("execution(* serveTo(..))")
    public void afterGreeting() throws Throwable {
        System.out.println("afterGreeting");
    }
}

结果输出

before aroudGreeting before
beforeGreeting
greet to John...
afterReturningGreeting
after aroudGreeting
serving John...
afterThrowingGreeting
afterGreeting

5.切点表达式

5.1@annotation
表示标记某个注解的所有方法

    @AfterReturning("@annotation(aop.smart.anno.NeedTest)")
    public void atAnnotaionTest(){
        System.out.println("atAnnotaionTest() executed!");
    }
    @NeedTest
    public void serveTo(String name){
        System.out.println("serving "+name+"...");

        //throw new RuntimeException();
    }

5.2 execution

5.3 args和@args

5.4 within

6.命名切点

public class TestNamePointcut {
    @Pointcut("within(com.smart.*)")
    private void inPackage(){}
//  
//  @Pointcut("execution(* greetTo(..)))")
//    protected void greetTo(){}
//
    @Pointcut("inPackage() and greetTo()")
    public void inPkgGreetTo(){}
}
    @Before("TestNamePointcut.inPkgGreetTo()")
    public void pkgGreetTo(){
        System.out.println("--pkgGreetTo() executed!--");
    }

7.排序(Ordered)

@Aspect
public class OrderGreetingAspect implements Ordered {
    @Around("execution(* greetTo(..))")
    public void beforeGreeting(ProceedingJoinPoint point) throws Throwable {
        System.out.println("OrderGreetingAspect");
        point.proceed();
    }


    @Override
    public int getOrder() {
        return 1;
    }
}

@Aspect
public class Order2GreetingAspect implements Ordered {
    @Around("execution(* greetTo(..))")
    public void beforeGreeting(ProceedingJoinPoint point) throws Throwable {
        System.out.println("Order2GreetingAspect");
        point.proceed();
    }

    @Override
    public int getOrder() {
        return 2;
    }
}

    @Test
    public void orderTest(){
        Waiter target = new NaiveWaiter();
        AspectJProxyFactory factory = new AspectJProxyFactory();
        factory.setTarget(target);
        factory.addAspect(OrderGreetingAspect.class);
        factory.addAspect(Order2GreetingAspect.class);
        Waiter proxy = factory.getProxy();
        proxy.greetTo("John");
        proxy.serveTo("John");
    }

测试结果:

OrderGreetingAspect
Order2GreetingAspect
greet to John...
serving John...

8.绑定连接点信息

如上ProceedingJoinPoint

9.绑定连接点方法入参

@Around("execution(* greetTo(..)) && args(name)")
    public void beforeGreeting(ProceedingJoinPoint point,String name) throws Throwable {
        System.out.println("Order2GreetingAspect");
        point.proceed();
    }