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 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();
    }

}

源码：learning-spring

学习 Spring (十五) Advisor

原文：https://www.cnblogs.com/victorbu/p/10504407.html