spring之AspectJ面向切面编程

spring之AspectJ面向切面编程

面向切面编程，实现方式有三种，最常用的是

1、实现InvocationHandler接口:这样需要根据代理的类

2、基于Spring 的AOP方式:这种和实现接口一样，也需要有个新的类来代理

3、基于Aspectj + 自定义注解来实现，这个很完美，对外调用不需要重写类

使用Aspectj注解实现切面编程

增加jar包：
dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.8.9</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.9</version>
        </dependency>
       
切面：
//使用@Aspect实现面向切面编程：如controller方法调用的耗时
@Aspect
@Component
public class TimerAspectInterceptor {

private Logger logger = LoggerFactory.getLogger(TimerAspectInterceptor.class);

@Pointcut("execution(* cn.web.controller.UserController..*(..))")
public void controllerMethodPointCut() {

}

//匹配那些有指定注解的连接点@Logable(带用这个注解的所有方法作为连接点)
@Pointcut("@annotation(cn.web.controller.Logable)")
public void multiMethodPointCut() {

}

/*@Before(value="controllerMethodPointCut()")
public void before2(JoinPoint point) {
Object[] args = point.getArgs();
logger.info("before..args={}", args.length);
}
@Before(value = "beforePointcut(param)", argNames = "param") 
public void beforeAdvice(String param) { 
          System.out.println("===========before advice param:" + param); 
}

@After("controllerMethodPointCut()")
public void after() {
logger.info("after..");
}

@AfterReturning(value = "controllerMethodPointCut()")
public void afterReturn() {
logger.info("afterReturn..");
}
*/
@AfterThrowing(value = "controllerMethodPointCut()")
public void afterThrow() {
logger.info("afterThrow..");
}

//@Around(value = "controllerMethodPointCut() || multiMethodPointCut()")
//@Around(value = "controllerMethodPointCut()")
@Around("multiMethodPointCut()") //环饶通知如果原有抛出异常，会调用afterThrow()
public void aroundControllerMethod(ProceedingJoinPoint joinPoint) throws Throwable {
long start = System.currentTimeMillis();
//回调目标的原有方法
joinPoint.proceed();
logger.info("op=look method={} cost={}", joinPoint.getSignature().getName(),
System.currentTimeMillis() - start);
}

}

连接点：
使用注解作为连接点

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Logable {
//long timeoutMillis() default 0;
}