https://github.com/enginooby-practice/spring-aop

Configured by Java code
https://github.com/enginooby-practice/spring-aop

java spring-aop

Last synced: 9 days ago
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Configured by Java code

• Host: GitHub
• URL: https://github.com/enginooby-practice/spring-aop
• Owner: enginooby-practice
• Created: 2020-07-07T14:03:41.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2020-08-18T16:18:59.000Z (over 4 years ago)
• Last Synced: 2024-11-07T15:37:58.276Z (2 months ago)
• Topics: java, spring-aop
• Language: Java
• Homepage:
• Size: 42.5 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Practice Topics

## Configuration

1. Add dependencies:

   - Spring framework [[URL]()]

   - AspectJ Weaver: supports AOP (avoid Beta version) 

[[URL](https://mvnrepository.com/artifact/org.aspectj/aspectjweaver)]

2. Create Spring AOP Java configuaration class with *__@Configuration__*, *__@EnableAspectJAutoProxy__*, *__@ComponentScan__* 

[[JavaConfig](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/JavaConfig.java)].

3. Create bean class with *__@Component__* 

[[Account](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/dao/AccountDAO.java)].

4. Create Main app class 

[[LoggingApp](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/LoggingApp.java)]

   1. Read Spring config Java class to get the context 

   ```

   AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(JavaConfig.class);

   ```

   2. Get bean class from Spring container 

   ```

   BeanClass aBean = context.getBean("aBean", BeanClass.class);

   ```

   3. Call business methods of the bean

   4. Close the context: ```context.close();```

5. Create Aspect class with *__@Aspect__* and *__@Component__* (to group related Advices) 

[[LoggingAspect](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/aspect/LoggingAspect.java)] 

   1. Setup logger [java.util.logging.Logger] or use *__@Logger__* from Lombok (to log Advices output in the same thread? as Spring)

   2. Setup Pointcut declarations with *__@Pointcut__* (to associate business methods of bean with Advices)

   3. Create Advices (to execute whatever code with associated business methods)

## Concepts

- *__@EnableAspectJAutoProxy__*

- AnnotationConfigApplicationContext

- Aspect with *__@Aspect__*

- Advice 

[[LoggingAspect](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/aspect/LoggingAspect.java)]

  - *__@Before:__* run before the method

  - *__@AfterReturning:__* run after the method (success execution), use *```returning```* to get returning result 

  - *__@AfterThrowing:__* run after the method (if exception thrown), use *```throwing```* and ```Throwable``` the capture the exception, can not handle exception

  - *__@After:__* run after the method (regardless of outcome)

  - *__@Around:__* run before and after the method, use ```ProceedingJoinPoint.proceed()``` to execute target method when desired,  can handle/rethrow exception using ```try catch``` block 

- Pointcut expression: ```execution(return_type package.class.method(params))```

  - Wildcards

[[LoggingAspect](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/aspect/LoggingAspect.java)]

    - (): no args

    - (*): one arg, any types

    - (..): zero or more args, any types

    - (fully qualified classname)

  - Declare with *__@Pointcut__* 

[[CommonAspect](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/aspect/CommonExpress.java)]

  - Combine pointcut expressions using &&, ||, !

[[CommonAspect](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/aspect/CommonExpress.java)]

- *__@Order:__* Decide the execution order of all Advices in a Aspect

  - Lower numbers have higher predence

  - Negative numbers are allowed

  - Does not have to be consecutive

- JoinPoint: contains metadata of the business method

[[TestingAspect](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/aspect/TestingAspect.java)]

  - Get method signature by ```MethodSignature``` and ```JoinPoint.getSignature()```

  - Get method parameters by ```Objec[]``` and ```JoinPoint.getArgs()```

## Notes - Tips

- 📌 Quick copy fully qualified classname from that class

- 📌 Group related advices into one Aspect to order with *__@Order__* (i.e., logging aspect, testing aspect)

- 📌 Declare public pointcut expressions in a common Aspect to share with other Aspects 

[[CommonAspect](https://github.com/cpulover-practice/spring-aop/blob/master/src/com/cpulover/aop/aspect/CommonExpress.java)].

- ℹ️ Order execution: *__@Before__* -> *__@Around__* (before) -> Business method -> *__@Around__* (after) -> *__@After__* -> *__@AfterThrowing__*