AOP实现方法

原文地址

http://michael-softtech.iteye.com/blog/650779

(1)使用ProxyFactoryBean的代理

Java代码

1. package chapter4;

2. public interface Performable {

3. public void perform() throws Exception;

4. }

5. package chapter4;

6. import java.util.Random;

7. public class Artist implements Performable {

8. public void perform() throws Exception {

9. int num = new Random().nextInt(100);

10. if(num >= 50) {

11. throw new Exception(String.valueOf(num));

12. } else {

13. System.out.println(num);

14. }

15. }

16. }

17. package chapter4;

18. public class Audience {

19. public Audience() {

20. }

21. public void takeSeats() {

22. System.out.println("The audience is taking their seats.");

23. }

24. public void turnOffCellPhones() {

25. System.out.println("The audience is turning off " + "their cellphones");

26. }

27. public void applaud() {

28. System.out.println("CLAP CLAP CLAP CLAP CLAP");

29. }

30. public void demandRefund() {

31. System.out.println("Boo! We want our money back!");

32. }

33. }

34. package chapter4;

35. import java.lang.reflect.Method;

36. import org.springframework.aop.AfterReturningAdvice;

37. import org.springframework.aop.MethodBeforeAdvice;

38. import org.springframework.aop.ThrowsAdvice;

39. public class AudienceAdvice

40. implements MethodBeforeAdvice, AfterReturningAdvice, ThrowsAdvice {

41. private Audience audience;

42. public void setAudience(Audience audience) {

43. this.audience = audience;

44. }

45. public void before(Method method, Object[] args, Object target)

46. throws Throwable {

47. audience.takeSeats();

48. audience.turnOffCellPhones();

49. }

50. public void afterReturning(Object returnValue, Method method, Object[] args,

51. Object target) throws Throwable {

52. audience.applaud();

53. }

54. public void afterThrowing(Exception ex) {

55. audience.demandRefund();

56. }

57. }

Xml代码

1. <?xml version="1.0" encoding="UTF-8"?>

2. <beans xmlns="http://www.springframework.org/schema/beans"

3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

4. xmlns:aop="http://www.springframework.org/schema/aop"

5. xmlns:tx="http://www.springframework.org/schema/tx"

6. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

7. <bean id="audience" class="chapter4.Audience" />

8. <bean id="audienceAdvice" class="chapter4.AudienceAdvice" >

9. <property name="audience" ref="audience" />

10. </bean>

11. <bean id="audienceAdvisor" class="org.springframework.aop.aspectj.AspectJExpressionPointcu

    tAdvisor">

12. <property name="advice" ref="audienceAdvice" />

13. <property name="expression" value="execution(* *.perform(..))" />

14. </bean>

15. <bean id="artistTarget" class="chapter4.Artist" />

16. <bean id="artist" class="org.springframework.aop.framework.ProxyFactoryBean" >

17. <property name="target" ref="artistTarget" />

18. <property name="interceptorNames" value="audienceAdvisor" />

19. <property name="proxyInterfaces" value="chapter4.Performable" />

20. </bean>

21. </beans>

(2)隐式使用ProxyFactoryBean的aop代理

DefaultAdvisorAutoProxyCreator实现了BeanPostProcessor，它将自动检查advisor的pointcut是否匹配bean的方法，如果匹配会替换bean为一个proxy，并且应用其advice。

Xml代码

1. <?xml version="1.0" encoding="UTF-8"?>

2. <beans xmlns="http://www.springframework.org/schema/beans"

3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

4. xmlns:aop="http://www.springframework.org/schema/aop"

5. xmlns:tx="http://www.springframework.org/schema/tx"

6. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

7. <bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyC

   reator" />

8. <bean id="audience" class="chapter4.Audience" />

9. <bean id="audienceAdvice" class="chapter4.AudienceAdvice" >

10. <property name="audience" ref="audience" />

11. </bean>

12. <bean id="audienceAdvisor" class="org.springframework.aop.aspectj.AspectJExpressionPointcu

    tAdvisor">

13. <property name="advice" ref="audienceAdvice" />

14. <property name="expression" value="execution(* *.perform(..))" />

15. </bean>

16. <bean id="artist" class="chapter4.Artist" />

17. </beans>

(3)使用注解的aop代理

xml中增加了一个<aop:aspectj-autoproxy />，它创建了AnnotationAwareAspectJAutoProxyCreator在spring中，这个类将自动代理匹配的类的放方法。和上个例子中DefaultAdvisorAutoProxyCreator做同样的工作。

Java代码

1. package chapter4;

2. import org.aspectj.lang.annotation.AfterReturning;

3. import org.aspectj.lang.annotation.AfterThrowing;

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

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

6. import org.aspectj.lang.annotation.Pointcut;

7. @Aspect

8. public class Audience {

9. public Audience() {

10. }

11. @Pointcut("execution(* *.perform(..))")

12. public void pointcut(){}

13. @Before("pointcut()")

14. public void takeSeats() {

15. System.out.println("The audience is taking their seats.");

16. }

17. @Before("pointcut()")

18. public void turnOffCellPhones() {

19. System.out.println("The audience is turning off " + "their cellphones");

20. }

21. @AfterReturning("pointcut()")

22. public void applaud() {

23. System.out.println("CLAP CLAP CLAP CLAP CLAP");

24. }

25. @AfterThrowing("pointcut()")

26. public void demandRefund() {

27. System.out.println("Boo! We want our money back!");

28. }

29. }

Xml代码

1. <?xml version="1.0" encoding="UTF-8"?>

2. <beans xmlns="http://www.springframework.org/schema/beans"

3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

4. xmlns:aop="http://www.springframework.org/schema/aop"

5. xmlns:tx="http://www.springframework.org/schema/tx"

6. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

7. <aop:aspectj-autoproxy />

8. <bean id="audience" class="chapter4.Audience" />

9. <bean id="artist" class="chapter4.Artist" />

10. </beans>

(4)使用aop配置文件的自动代理

采用这种方法，不用加<aop:aspectj-autoproxy />

Java代码

1. package chapter4;

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

3. @Aspect

4. public class Audience {

5. public Audience() {

6. }

7. public void pointcut() {

8. }

9. public void takeSeats() {

10. System.out.println("The audience is taking their seats.");

11. }

12. public void turnOffCellPhones() {

13. System.out.println("The audience is turning off " + "their cellphones");

14. }

15. public void applaud() {

16. System.out.println("CLAP CLAP CLAP CLAP CLAP");

17. }

18. public void demandRefund() {

19. System.out.println("Boo! We want our money back!");

20. }

21. }

Xml代码

1. <?xml version="1.0" encoding="UTF-8"?>

2. <beans xmlns="http://www.springframework.org/schema/beans"

3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

4. xmlns:aop="http://www.springframework.org/schema/aop"

5. xmlns:tx="http://www.springframework.org/schema/tx"

6. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

7. <bean id="audience" class="chapter4.Audience" />

8. <aop:config>

9. <aop:aspect ref="audience">

10. <aop:before method="takeSeats" pointcut="execution(* *.perform(..))" />

11. <aop:before method="turnOffCellPhones" pointcut="execution(* *.perform(..))" />

12. <aop:after-returning method="applaud" pointcut="execution(* *.perform(..))" />

13. <aop:after-throwing method="demandRefund" pointcut="execution(* *.perform(..))" />

14. </aop:aspect>

15. </aop:config>

16. <bean id="artist" class="chapter4.Artist" />

17. </beans>