spring学习--4

参考书籍《spring in action》

 

1. AOP

before you wak the walk, you have to learn to walk the walk.

1) advice---the job of an aspect (what and when)

/before

/after

/after-returning

/after throwing

/around: beforen and after

2) join points---a point in the execution of the application where an aspect can be plugged in.

3)pointcuts---where the advice should be woven

4)aspects--- advice & joincuts

5)introduction---add new methods or attributes to existing classes.

6)weaving---the process of applyng aspects to target object to create a

 new proxied object.

/compile time

/class load time

/runtime

2. spring 对AOP的支持方式

1）classic spring proxy-based AOP

2）pure-POJO aspects

3) @AspectJ annotation driven aspects.

4) injected AspectJ aspects.

 

3.creating aspect in spring

1）selecting join points with pointcuts.

eg:

execution(* concert.Performance.perform())
and bean('woodstock')

2) creating annotated aspects

@Aspect
public class Audience {
@Pointcut("execution(** concert.Performance.perform(..))")
public void performance() {}
@Before("performance()")
public void silenceCellPhones() {
System.out.println("Silencing cell phones");
}
@Before("performance()")
public void takeSeats() {
System.out.println("Taking seats");
}
@AfterReturning("performance()")
public void applause() {
System.out.println("CLAP CLAP CLAP!!!");
}
@AfterThrowing("performance()")
public void demandRefund() {
System.out.println("Demanding a refund");
}
}

配置：

@Configuration
@EnableAspectJAutoProxy
@ComponentScan
public class ConcertConfig {
@Bean
public Audience audience() {
return new Audience();
}
}

3）handling params in advice

4) annotation introductions

dynamic language like ruby and groovy can add new methods to an object or class.