如果咱们在同一个办法自定义多个AOP，如何执行执行程序？
有一种答案是指定order，order越小越先执行。这种答案不算错，然而有些全面。
更改Aspect的Order有三中形式，1：通过实现org.springframework.core.Ordered接口；2：通过注解@Order(1) ；3：通过配置文件配置
咱们试验采纳注解的形式，定义两个Aspect：
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Log {
String description() default "";
}
order=1001
代码块
java
@Aspect
@Component
@Order(1001)
public class LogAspect {
private final Logger logger \= LoggerFactory.getLogger(this.getClass());
//日志注解
@Pointcut(value \= "@annotation(com.meituan.pay.mapi.aspect.Log)")
public void logAspect() {
}
//申明前置告诉
@Before("logAspect()")
public void doBefore(JoinPoint point) {
logger.info("logAspect:doBefore");
return;
}
//申明后置告诉
@AfterReturning(pointcut \= "logAspect()", returning \= "returnValue")
public void doAfterReturning(JoinPoint point, Object returnValue) {
logger.info("logAspect:doAfterReturning");
}
//申明例外告诉
@AfterThrowing(pointcut \= "logAspect()", throwing \= "e")
public void doAfterThrowing(Exception e) {
logger.info("logAspect:doAfterThrowing");
}
//申明最终告诉
@After("logAspect()")
public void doAfter() {
logger.info("logAspect:doAfter");
}
//申明盘绕告诉
@Around("logAspect()")
public Object doAround(ProceedingJoinPoint pjp) throws Throwable {
logger.info("logAspect:doAround-start");
Object obj \= pjp.proceed();
logger.info("logAspect:doAround-end");
return obj;
}
}
**SignAspect：**
代码块
java
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Sign {
String description() default "";
}
order=1002
代码块
java
@Aspect
@Component
@Order(1002)
public class SignAspect {
private final Logger logger \= LoggerFactory.getLogger(this.getClass());
//日志注解
@Pointcut(value \= "@annotation(com.meituan.pay.mapi.aspect.Sign)")
public void signAspect() {
}
//申明前置告诉
@Before("signAspect()")
public void doBefore(JoinPoint point) {
logger.info("signAspect:doBefore");
return;
}
//申明后置告诉
@AfterReturning(pointcut \= "signAspect()", returning \= "returnValue")
public void doAfterReturning(JoinPoint point, Object returnValue) {
logger.info("signAspect:doAfterReturning");
}
//申明例外告诉
@AfterThrowing(pointcut \= "signAspect()", throwing \= "e")
public void doAfterThrowing(Exception e) {
logger.info("signAspect:doAfterThrowing");
}
//申明最终告诉
@After("signAspect()")
public void doAfter() {
logger.info("signAspect:doAfter");
}
//申明盘绕告诉
@Around("signAspect()")
public Object doAround(ProceedingJoinPoint pjp) throws Throwable {
logger.info("signAspect:doAround-start");
Object obj \= pjp.proceed();
logger.info("signAspect:doAround-end");
return obj;
}
}
**测试：**
代码块
java
@Service
public class AspectTestService {
private static final Logger LOGGER \= LoggerFactory.getLogger(AspectTestService.class);
@Sign
@Log
public void testAspect() {
LOGGER.info("执行办法");
}
}
**最终输入：**
代码块
java
LogAspect (LogAspect.java:55) logAspect:doAround\-start
LogAspect (LogAspect.java:30) logAspect:doBefore
SignAspect (SignAspect.java:54) signAspect:doAround\-start
SignAspect (SignAspect.java:29) signAspect:doBefore
AspectTestService (AspectTestService.java:19) 执行办法
SignAspect (SignAspect.java:56) signAspect:doAround\-end
SignAspect (SignAspect.java:48) signAspect:doAfter
SignAspect (SignAspect.java:36) signAspect:doAfterReturning
LogAspect (LogAspect.java:57) logAspect:doAround\-end
LogAspect (LogAspect.java:49) logAspect:doAfter
LogAspect (LogAspect.java:37) logAspect:doAfterReturning
**论断：**
从下面的测试咱们看到，的确是order越小越是最先执行，但更重要的是最先执行的最初完结。
AOP就是面向切面编程，什么是切面，画一个图来了解下：
由此得出：
- spring aop就是一个同心圆，要执行的办法为圆心，最外层的order最小
- 从最外层依照LogAspect、SignAspect的程序顺次执行doAround办法，doBefore办法
- 而后执行method办法
- 最初依照SignAspect、LogAspect的程序顺次执行doAfter、doAfterReturn办法
- 也就是说对多个AOP来说，先before的，肯定后after
利用举例：
如果咱们要在同一个办法事务提交后执行本人的AOP，那么把事务的AOP order设置为2，本人的AOP order设置为1，而后在doAfterReturn里边解决本人的业务逻辑
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