advisor 就像一个小的自包含的方面，只有一个 advice
切面自身通过一个 bean 表示，并且必须实现某个 advice 接口，同时 advisor 也可以很好的利用 AspectJ 的切入点表达式
Spring 通过配置文件中 aop:advisor 元素支持 advisor，实际使用中，大多数情况下它会和 transactional advice 配合使用
为了定义一个 advisor 的优先级以便让 advice 可以有序，可以使用 order 属性来定义 advisor 的顺序
示例
添加切面：
public class ConcurrentOperationExecutor implements Ordered {
private static final int DEFAULT_MAX_RETRIES = 2;
private int maxRetries = DEFAULT_MAX_RETRIES;
private int order = 1;
public void setMaxRetries(int maxRetries) {
this.maxRetries = maxRetries;
}
public int getOrder() {
return this.order;
}
public void setOrder(int order) {
this.order = order;
}
public Object doConcurrentOperation(ProceedingJoinPoint pjp) throws Throwable {
int numAttempts = 0;
PessimisticLockingFailureException lockFailureException;
do {
numAttempts++;
System.out.println("Try times : " + numAttempts);
try {
return pjp.proceed();
} catch (PessimisticLockingFailureException ex) {
lockFailureException = ex;
}
} while (numAttempts <= this.maxRetries);
System.out.println("Try error : " + numAttempts);
throw lockFailureException;
}
}
添加类：
@Service
public class InvokeService {
public void invoke() {
System.out.println("InvokeService ......");
}
public void invokeException() {
throw new PessimisticLockingFailureException("");
}
}
添加配置：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<context:component-scan base-package="com.karonda.aop.schema"></context:component-scan>
<aop:config>
<aop:aspect id="concurrentOperationRetry" ref="concurrentOperationExecutor">
<aop:pointcut id="idempotentOperation"
expression="execution(* com.karonda.aop.schema.advisors.service.*.*(..)) " />
<aop:around pointcut-ref="idempotentOperation" method="doConcurrentOperation" />
</aop:aspect>
</aop:config>
<bean id="concurrentOperationExecutor" class="com.karonda.aop.schema.advisors.ConcurrentOperationExecutor">
<property name="maxRetries" value="3" />
<property name="order" value="100" />
</bean>
</beans>
添加测试类：
@RunWith(BlockJUnit4ClassRunner.class)
public class TestAOPSchemaAdvisors extends UnitTestBase {
public TestAOPSchemaAdvisors() {
super("classpath:spring-aop-schema-advisors.xml");
}
@Test
public void testSave() {
InvokeService service = super.getBean("invokeService");
service.invoke();
System.out.println();
service.invokeException();
}
}