Spring AOP @AspectJ进阶

@AspectJ可以使用切点函数定义切点，我们还可以使用逻辑运算符对切点进行复核运算得到复合的切点，为了在切面中重用切点，我们还可以对切点进行命名，以便在其他的地方引用定义过的切点。当一个连接点匹配多个切点时，需要考虑织入顺序的问题，此外一个重要的问题是如何再增强中访问连接点上下文的信息。

Waiter接口：

package com.yyq.aspectJAdvanced;
public interface Waiter {
    void greetTo(String name);
    void serveTo(String name);
}

NaiveWaiter实现类：

package com.yyq.aspectJAdvanced;
public class NaiveWaiter implements Waiter {
    @Override
    public void greetTo(String name) {
        System.out.println("NaiveWaiter：greet to " + name + "...");
    }
    @Override
    public void serveTo(String name) {
        System.out.println("NaiveWaiter：serving to " + name + "...");
    }
    public void smile(String clientName,int times){
        System.out.println("NaiveWaiter:smile to  "+clientName+ times+"times...");
    }
}

 NaughtyWaiter实现类：

package com.yyq.aspectJAdvanced;
public class NaughtyWaiter implements Waiter {
    public void greetTo(String clientName) {
        System.out.println("NaughtyWaiter:greet to " + clientName + "...");
    }
    public void serveTo(String clientName) {
        System.out.println("NaughtyWaiter:serving " + clientName + "...");
    }
    public void joke(String clientName, int times) {
        System.out.println("NaughtyWaiter:play " + times + " jokes to " + clientName + "...");
    }
}

Seller接口：

package com.yyq.aspectJAdvanced;
public interface Seller {
  int sell(String goods, String clientName);
}

SmallSeller实现类：

package com.yyq.aspectJAdvanced;
public class SmartSeller implements Seller {
    public int sell(String goods,String clientName) {
        System.out.println("SmartSeller: sell "+goods +" to "+clientName+"...");
        return 100;
    }

    public void checkBill(int billId){
        if(billId == 1) throw new IllegalArgumentException("iae Exception");
        else throw new RuntimeException("re Exception");
    }
}

beans.xml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:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
    <aop:aspectj-autoproxy proxy-target-class="true"/>
    <bean id="naiveWaiter" class="com.yyq.aspectJAdvanced.NaiveWaiter"/>
    <bean id="naughtyWaiter" class="com.yyq.aspectJAdvanced.NaughtyWaiter"/>
    <bean id="seller" class="com.yyq.aspectJAdvanced.SmartSeller"/>
 <!--
    <bean class="com.yyq.aspectJAdvanced.TestAspect"/>

    <bean class="com.yyq.aspectJAdvanced.TestAspect2"/>
    <bean class="com.yyq.aspectJAdvanced.TestAspect3"/>
    <bean class="com.yyq.aspectJAdvanced.TestAspect4"/>
    <bean class="com.yyq.aspectJAdvanced.TestAspect5"/>
    <bean id="naiveWaiter2" class="com.yyq.aspectJAdvanced.NaiveWaiter2"/>
    <bean class="com.yyq.aspectJAdvanced.TestAspect6"/>
    <bean class="com.yyq.aspectJAdvanced.TestAspect7"/>
    <bean class="com.yyq.aspectJAdvanced.TestAspect8"/>
-->
</beans>

1、切点符合运算

    使用切点符合运算符，我们将拥有强大而灵活的切点表达能力。

TestAspect：切点符合运算定义切面

package com.yyq.aspectJAdvanced;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class TestAspect {
    //与非运算
    @Before("!target(com.yyq.aspectJAdvanced.NaiveWaiter) && execution(* serveTo(..))")
    public void notServeInNaiveWaiter(){
        System.out.println("--notServeInNaiveWaiter() executed!--");
    }
    //与运算
    @After("within(com.yyq.aspectJAdvanced.*) && execution(* greetTo(..))")
    public void greetToFun(){
        System.out.println("--greetToFun() executed!--");
    }
    //或运算
    @AfterReturning("target(com.yyq.aspectJAdvanced.Waiter) || target(com.yyq.aspectJAdvanced.Seller)")
    public void waiterOrSeller(){
        System.out.println("--waiterOrSeller() executed!--");
    }
}

测试方法：

 @Test
    public void pointAspectJTest() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        Waiter naiveWaiter = (Waiter) ctx.getBean("naiveWaiter");
        Waiter naughtyWaiter = (Waiter) ctx.getBean("naughtyWaiter");
        naiveWaiter.greetTo("John");
        naiveWaiter.serveTo("John");
        naughtyWaiter.greetTo("Tom");
        naughtyWaiter.serveTo("Tom");
    }

输出结果：

NaiveWaiter：greet to John...

--greetToFun() executed!--

--waiterOrSeller() executed!--

NaiveWaiter：serving to John...

--waiterOrSeller() executed!--

NaughtyWaiter:greet to Tom...

--greetToFun() executed!--

--waiterOrSeller() executed!--

--notServeInNaiveWaiter() executed!--

NaughtyWaiter:serving Tom...

--waiterOrSeller() executed!--

 

2、命名切点

    切点直接声明在增强方法处被称为匿名切点，匿名切点只能在声明处使用。如果希望在其他地方重用一个切点，我们可以通过@Pointcut注解以及切面类方法对切点进行命名。

TestNamePointcut：命名切点类

package com.yyq.aspectJAdvanced;
import org.aspectj.lang.annotation.Pointcut;
public class TestNamePointcut {
    //通过注解方法inPackage()对该切点进行命名，方法可视域修饰符为private，表明该命名切点只能在本切面类中使用
    @Pointcut("within(com.yyq.aspectJAdvaned.*)")
    private void inPackage(){}
    @Pointcut("execution(* greetTo(..))")
    protected void greetTo(){}
    @Pointcut("inPackage() and greetTo()")
    public void inPkgGreetTo(){}
}

TestAspect2：切面实现类

package com.yyq.aspectJAdvanced;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
@Aspect
public class TestAspect2 {
    @Before("TestNamePointcut.inPkgGreetTo()")
    public void pkgGreetTo(){
        System.out.println("--pkgGreetTo() executed!--");
    }
    @Before("target(com.yyq.aspectJAdvanced.NaiveWaiter) || TestNamePointcut.inPkgGreetTo()")
    public void pkgGreetToNotnaiveWaiter(){
        System.out.println("--pkgGreetToNotnaiveWaiter() executed!--");
    }
}

测试方法：

@Test
    public void pointAspectJTest2() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        NaiveWaiter naiveWaiter = (NaiveWaiter) ctx.getBean("naiveWaiter");
        naiveWaiter.smile("Andy", 2);
    }

输出结果：

--pkgGreetToNotnaiveWaiter() executed!--

NaiveWaiter:smile to  Andy2times...

 

3、增强织入的顺序

    一个连接点可以同时匹配多个切点，切点对应的增强在连接点上的织入顺序的安排主要有以下3种情况：

    1）如果增强在同一个切面类中声明，则依照增强在切面类中定义的顺序进行织入；

    2）如何增强位于不同的切面类中，且这些切面类都实现了org.springframework.core.Order接口，则由接口方法的顺序号决定（顺序号小的先织入）；

    3）如果增强位于不同的切面类中，且这些切面类没有实现org.springframework.core.Order接口，织入的顺序是不确定的。

 

4、访问连接点信息

    AspectJ使用org.aspectj.lang.JoinPoint接口表示目标类连接点对象，如果是环绕增强时，使用org.aspectj.lang.ProceedingJoinPoint表示连接点对象，该类是JoinPoint的子接口，任何一个增强方法都可以通过将第一个入参声明为JoinPoint访问到连接点上下文的信息。

TestAspect3：切面实现类

@Aspect
public class TestAspect3 {
    @Around("execution(* greetTo(..)) && target(com.yyq.aspectJAdvanced.NaiveWaiter)")
    public void joinPointAccess(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("---joinPointAccess---");
        System.out.println("args[0]:" + pjp.getArgs()[0]);
        System.out.println("signature:" + pjp.getTarget().getClass());
        pjp.proceed();
        System.out.println("---joinPointAccess---");
    }
}

测试方法：

 @Test
    public void pointAspectJTest3() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        Waiter naiveWaiter = (Waiter) ctx.getBean("naiveWaiter");
        naiveWaiter.greetTo("Andy");
    }

输出结果：

---joinPointAccess---

args[0]:Andy

signature:class com.yyq.aspectJAdvanced.NaiveWaiter

NaiveWaiter：greet to Andy...

---joinPointAccess---

 

5、绑定连接点方法入参

    args()用于绑定连接点方法的入参；@annotation()用于绑定连接点方法的注解对象；而@args()用于绑定连接点方法入参的注解。

TestAspect4：切面实现类

@Aspect
public class TestAspect4 {
    @Before("target(com.yyq.aspectJAdvanced.NaiveWaiter) && args(name,num,..)")
    public void bindJoinPointParams(int num, String name) {
        System.out.println("---bindJoinPointParams---");
        System.out.println("name:" + name);
        System.out.println("num:" + num);
        System.out.println("---bindJoinPointParams---");
    }
}

测试方法：

@Test
    public void pointAspectJTest4() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        NaiveWaiter naiveWaiter = (NaiveWaiter) ctx.getBean("naiveWaiter");
        naiveWaiter.smile("Andy", 3);
    }

输出结果：

---bindJoinPointParams---

name:Andy

num:3

---bindJoinPointParams---

NaiveWaiter:smile to  Andy 3 times...

 

6、绑定代理对象

    使用this()或target()可绑定被代理对象实例，在通过类实例名绑定对象时，还依然具有原来连接点匹配的功能，只不过类名是通过增强方法中同名入参的类型间接决定罢了。

TestAspect5：切面实现类

@Aspect
public class TestAspect5 {
    @Before("this(waiter)")
    public void bindProxyObj(Waiter waiter){
        System.out.println("---bindProxyObj---");
        System.out.println(waiter.getClass().getName());
        System.out.println("---bindProxyObj---");
    }
}

测试方法：

@Test
    public void pointAspectJTest5() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        Waiter waiter = (Waiter) ctx.getBean("naiveWaiter");
        waiter.greetTo("Yang");
    }

输出结果：

---bindProxyObj---

com.yyq.aspectJAdvanced.NaiveWaiter$$EnhancerByCGLIB$$fefafe52

---bindProxyObj---

NaiveWaiter：greet to Yang...

 

7、绑定类注解对象

    @within()和@target()函数可以将目标类的注解对象绑定到增强方法中，我们通过@within()演示注解绑定的操作。

TestAspect6：切面测试类

@Aspect
public class TestAspect6 {
    @Before("@within(m)")
    public void bindTypeAnnoObject(Monitorable m) {
        System.out.println("---bindTypeAnnoObject---");
        System.out.println(m.getClass().getName());
        System.out.println("---bindTypeAnnoObject---");
    }
}

测试方法：

@Test
    public void pointAspectJTest6() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        Waiter waiter = (Waiter) ctx.getBean("naiveWaiter2");
        ((NaiveWaiter2)waiter).greetTo("Yang");
    }

输出结果：

---bindTypeAnnoObject---

$Proxy4

---bindTypeAnnoObject---

NaiveWaiter：greet to Yang...

 

8、绑定返回值

    在后置增强中，我们可以通过returning绑定连接点方法的返回值。

TestAspect7：切面实现类

@Aspect
public class TestAspect7 {
    @AfterReturning(value = "target(com.yyq.aspectJAdvanced.SmartSeller)", returning = "retVal")
    public void bindReturnValue(int retVal) {
        System.out.println("---bindReturnValue---");
        System.out.println("returnValue:" + retVal);
        System.out.println("---bindReturnValue---");
    }
}

测试方法：

 @Test
    public void pointAspectJTest7() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        SmartSeller seller = (SmartSeller) ctx.getBean("seller");
        seller.sell("Beer", "John");
    } 

输出结果：

SmartSeller: sell Beer to John...

---bindReturnValue---

returnValue:100

---bindReturnValue---

 

9、绑定抛出的异常

    和通过切点函数绑定连接点信息不同，连接点抛出的异常必须使用AfterThrowing注解的throwing成员进行绑定。

TestAspect8：切面实现类

@Aspect
public class TestAspect8 {
    @AfterThrowing(value = "target(com.yyq.aspectJAdvanced.SmartSeller)", throwing = "iae")
    public void bindException(IllegalArgumentException iae) {
        System.out.println("---bindException---");
        System.out.println("exception:" + iae.getMessage());
        System.out.println("---bindException---");
    }
}

测试方法：

 @Test
    public void pointAspectJTest8() {
        String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
        SmartSeller seller = (SmartSeller) ctx.getBean("seller");
        seller.checkBill(1);
    }

输出结果：

---bindException---

exception:iae Exception

---bindException---

 

java.lang.IllegalArgumentException: iae Exception