与大多数技术一样, AOP 已经形成了自己的术语。描述切面的常用术语有通知(advice)、切点(pointcut)和连接点(join point)。从今天开始,我们对spring的切面编程做一个总结。她们都是你漫漫长路上,只配错过的好姑娘。
spring中的aop
spring的切面可以应用以下的5种类型的通知:
- 前置通知(Before):在目标方法被调用之前调用通知功能;
- 后置通知(After):在目标方法完成之后调用通知,此时不会关心方法的输出是什么;
- 返回通知(After-returning):在目标方法成功执行之后调用通知;
- 异常通知(After-throwing):在目标方法抛出异常后调用通知;
- 环绕通知(Around):通知包裹了被通知的方法,在被通知的方法调用之前和调用之后执行自定义的行为。
对于spring中aop的支持,主要分为@AspectJ 注解驱动的切面和基于xml的spring的配置。以下我们对这两种配置做一个简单的了解。测试的代码目录如下:
以后可能对于spring的关于aop学习,这个目录可能会添加代码。application-xml.xml是学习xml配置的,application-aop.xml是学习@Aspectj注解配置的。
springaop的xml配置方式
一、我们的application-xml.xml文件内容如下:
<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"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"><bean id="myService" class="com.linux.huhx.business.service.MyAspectService3"/><bean id="myAspect" class="com.linux.huhx.aspect.XmlUserfulAspect"/><aop:config><aop:aspect id="xmlAspect1" ref="myAspect"><aop:pointcut id="businessService" expression="execution(* com.linux.huhx.business.service.MyAspectService3.*())"/><aop:before method="beforeExecute" pointcut-ref="businessService"/><aop:after method="afterExecute" pointcut-ref="businessService"/></aop:aspect></aop:config> </beans>
二、我们的切面类XmlUserfulAspect如下:
package com.linux.huhx.aspect;/*** @Author: huhx* @Date: 2017-12-15 下午 12:31* @Desc: 切面类*/ public class XmlUserfulAspect {public void beforeExecute() {System.out.println("before execute.");}public void afterExecute() {System.out.println("after execute.");} }
三、我们简单的定义一个应用切面的服务类
package com.linux.huhx.business.service;/*** @Author: huhx* @Date: 2017-12-15 下午 12:28*/ public class MyAspectService3 {public void serviceMethod() {System.out.println("my aspect service1 method.");} }
四、在main的类中我们对上述的切面进行测试
package com.linux.huhx.main;import com.linux.huhx.business.service.MyAspectService3; import org.junit.Before; import org.junit.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;/*** @Author: huhx* @Date: 2017-12-15 下午 12:32* @Desc: 基于xml配置的aop测试主体类*/ public class XmlServiceMain {private ApplicationContext context = null;@Beforepublic void initApplicationContext() {context = new ClassPathXmlApplicationContext("application-xml.xml");}@Testpublic void aspectServiceTest_1() {MyAspectService3 myAspectService1 = context.getBean("myService", MyAspectService3.class);myAspectService1.serviceMethod();} }
打印的结果如下:
before execute.
my aspect service1 method.
after execute.
springaop中关于注解的方式
这里面设计的代码比较多,主要是为了测试不同的知识点。这里全部贴出代码,后续再做整理。后续我们对这两种的配置方式做一个比较细致的过程讲解。使用aspectj,我们需要在pom.xml文件中添加依赖:
<dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.8.11</version> </dependency>
一、application-aop.xml的文件内容如下
<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"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"><aop:aspectj-autoproxy/><bean id="myService1" class="com.linux.huhx.business.service.MyAspectService1"/><bean id="myService2" class="com.linux.huhx.business.service.MyAspectService2"/><!--declare an aspect--><bean id="myAspect" class="com.linux.huhx.aspect.NotVeryUsefulAspect"/><bean id="myAspect1" class="com.linux.huhx.aspect.LittleUserfulAspect"/> </beans>
二、两个测试切面的服务类如下:
- MyAspectService1:这里面主要测试切面的5种类型的通知。
package com.linux.huhx.business.service;import java.io.FileNotFoundException;/*** @Author: huhx* @Date: 2017-12-15 上午 10:08* @Desc: 一个简单的测试aspect的实类*/ public class MyAspectService1 {public void serviceMethod() {System.out.println("myaspect service1 method.");}public String returnServiceMethod() {return "return huhx.";}public String throwExceptionMethod() {System.out.println("throw exception method.");try {throw new FileNotFoundException("not found class.");} catch (FileNotFoundException e) {e.printStackTrace();}return "hello world";}public String aroundServiceMethod1() {System.out.println("around service method.");return "huhx";} }
- MyAspectService2.java:这里面测试切面传递参数。
package com.linux.huhx.business.service;import java.util.Map;/*** @Author: huhx* @Date: 2017-12-15 上午 11:17*/ public class MyAspectService2 {public void serviceMethod_1(Map<String, String> map) {System.out.println("service method." + map);} }
三、两个切面的类如下
- NotVeryUsefulAspect:是针对于上述的MyAspectService1类的,为了测试5种通知类型。
package com.linux.huhx.aspect;import org.aspectj.lang.ProceedingJoinPoint; import org.aspectj.lang.annotation.*;/*** @Author: huhx* @Date: 2017-12-15 上午 9:51* @Desc: 定义一个aspect*/@Aspect public class NotVeryUsefulAspect {private static final String pointCutString = "execution(* com.linux.huhx.business.service.MyAspectService1.*())";@Before(pointCutString)public void beforeExecute() {System.out.println("before advice.");}@After(pointCutString)public void afterExecute() {System.out.println("after advice.");}@AfterReturning(value = pointCutString, returning = "retVal")public void afterReturingExecute1(String retVal) {System.out.println("after throwing " + retVal);}@AfterThrowing(value = pointCutString, throwing = "exception")public void afterThrowingExecute1(Throwable exception) {System.out.println("throwing in advice show message: " + exception.getMessage());}@Around(value = pointCutString)public void arundExecute1(ProceedingJoinPoint pjp) throws Throwable{System.out.println("before around.");System.out.println(pjp.proceed());System.out.println("after around.");} }
- LittleUserfulAspect:是对应于MyAspectService2类的,为了测试切面中参数的传递。
package com.linux.huhx.aspect;import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut;import java.util.Map;/*** @Author: huhx* @Date: 2017-12-15 上午 11:16* @Desc: 定义一个切面*/ @Aspect public class LittleUserfulAspect {@Pointcut("execution(* com.linux.huhx.business.service.MyAspectService2.*(..)) && args(map,..)")public void anyMethod(Map<String, String> map) {}@Before(value = "anyMethod(map)")public void beforeExecute(Map map) {System.out.println("before execute." + map);} }
四、我们的测试主体类ServiceMain
package com.linux.huhx.main;import com.linux.huhx.business.service.MyAspectService1; import com.linux.huhx.business.service.MyAspectService2; import org.junit.Before; import org.junit.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;import java.util.HashMap; import java.util.Map;/*** @Author: huhx* @Date: 2017-12-15 上午 10:13* @Desc: 测试的main类*/ public class ServiceMain {private ApplicationContext context = null;@Beforepublic void initApplicationContext() {context = new ClassPathXmlApplicationContext("application-aop.xml");}@Testpublic void aspectServiceTest_1() {MyAspectService1 myAspectService1 = context.getBean("myService1", MyAspectService1.class);myAspectService1.serviceMethod();}@Testpublic void aspectServiceTest_2() {MyAspectService1 myAspectService1 = context.getBean("myService1", MyAspectService1.class);myAspectService1.returnServiceMethod();}@Testpublic void aspectServiceTest_3() {MyAspectService1 myAspectService1 = context.getBean("myService1", MyAspectService1.class);myAspectService1.throwExceptionMethod();}@Testpublic void aspectServiceTest_4() {MyAspectService1 myAspectService1 = context.getBean("myService1", MyAspectService1.class);myAspectService1.aroundServiceMethod1();}/* 其它的切面实现类 */@Testpublic void aspectServiceTest_5() {MyAspectService2 myAspectService2 = context.getBean("myService2", MyAspectService2.class);Map<String, String> dataMap = new HashMap<>();dataMap.put("username", "linux");dataMap.put("password", "12345");myAspectService2.serviceMethod_1(dataMap);} }
友情链接