快速入门
基于注解的AOP开发步骤：
- 创建目标接口和目标类(内部有切点)
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| package cn.imqinhao.anno;
public interface TargetInterface {
public void save();
}
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| package cn.imqinhao.anno;
import org.springframework.stereotype.Component;
public class Target implements TargetInterface {
@Override
public void save() {
System.out.println("save running...");
}
}
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- 创建切面类(内部有增强方法)
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| package cn.imqinhao.anno;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
public class MyAspect {
public void before() {
System.out.println("前置增强...");
}
}
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- 将目标类和切面类的对象创建权交给spring
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| package cn.imqinhao.anno;
import org.springframework.stereotype.Component;
@Component("target")
public class Target implements TargetInterface {
@Override
public void save() {
System.out.println("save running...");
}
}
|
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| package cn.imqinhao.anno;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
/**
* @author qinhao
* @version 1.0
*/
@Component("myAspect")
public class MyAspect {
public void before() {
System.out.println("前置增强...");
}
}
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- 在切面类中使用注解配置织入关系
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| package cn.imqinhao.anno;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
@Component("myAspect")
@Aspect
public class MyAspect {
@Before("execution(* cn.imqinhao.anno.*.*(..))")
public void before() {
System.out.println("前置增强...");
}
}
|
- 在配置文件中开启组件扫描和AOP的自动代理
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| <?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:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
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/context http://www.springframework.org/schema/context/spring-context.xsd
">
<context:component-scan base-package="cn.imqinhao.anno" />
<aop:aspectj-autoproxy />
</beans>
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- 测试
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| package cn.imqinhao.test;
import cn.imqinhao.anno.TargetInterface;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext-anno.xml")
public class AnnoTest {
@Autowired
private TargetInterface target;
@Test
public void test1() {
target.save();
}
}
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运行结果：
前置增强…
save running…
注解通知的类型
通知的配置语法：@通知注解(“切点表达式”)
切点表达式的抽取
同xml配置aop一样，我们可以将切点表达式抽取。抽取方式是在切面内定义方法，在该方法上使用@Pointcut注解定义切点表达式，然后在在增强注解中进行引用。具体如下:
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| package cn.imqinhao.anno;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;
@Component("myAspect")
@Aspect
public class MyAspect {
@Around("pointCut()")
public Object around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
System.out.println("环绕前增强...");
Object proceed = proceedingJoinPoint.proceed();
System.out.println("环绕后增强...");
return proceed;
}
@After("MyAspect.pointCut()")
public void after() {
System.out.println("最终增强...");
}
@Pointcut("execution(* cn.imqinhao.anno.*.*(..))")
public void pointCut(){}
}
|
运行结果：
环绕前增强…
save running…
环绕后增强…
最终增强…
