Spring入门篇学习笔记

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();

 	}

}

巴特西

学习 Spring (十五) Advisor

示例

源码：learning-spring

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