Aop（面向切面编程）
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使用注解的方式：
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加入相应的jar包：
- com.springsource.org.aopalliance-1.0.0.jar
- com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar
- sping-aspects-4.3.3.RELEASE.jar
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创建一个切面类
package com.alibaba.wlq.invoke; import java.util.Arrays; import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
//@Aspect:表示该类为切面类
@Aspect
//@Component:表示该类由Spring管理
@Component
public class logAspect {
//@Before:表示before方法在被通知的程序类的方法执行之前执行
//execution():表示需要被通知的类中的add方法，add方法可以用通配符表示，那就表示该类中所有的方法都要被通知
@Before(value="execution(* com.alibaba.wlq.invoke.ArithmeticImp.add(double,double))")
//JoinPoint:是程序执行中的一个精确执行点，例如类中的一个方法。它是一个抽象的概念，在实现AOP时，并不需要去定义一个join point
public void before(JoinPoint joinpoint) {
//获得被通知程序类的参数，返回类型是一个数组
Object[] args = joinpoint.getArgs();
//获取被通知程序类的方法名，返回类型是字符串
String name = joinpoint.getSignature().getName();
System.out.println("alibaba------>the method "+name+" begin with"+Arrays.asList(args));
} //@After:后置通知，表示在类的方法执行后、类中的return方法执行前执行
@After(value="execution(* com.alibaba.wlq.invoke.ArithmeticImp.add(double,double))")
public void after() {
System.out.println("alibaba------>the method *** end result");
}
} -
创建被通知的类的接口
package com.alibaba.wlq.invoke; public interface Arithmetic {
public double add(double a,double b);
} -
创建被通知的类并且继承接口重写其中的方法
package com.alibaba.wlq.invoke; import org.springframework.stereotype.Component; @Component
public class ArithmeticImp implements Arithmetic{ @Override
public double add(double a, double b) {
double result = a + b;
System.out.println(result);
return result;
} } -
配置文件中的配置
<?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-4.2.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd"> <!-- 包扫描，前提加入aop的jar包 -->
<context:component-scan base-package="com.alibaba.wlq"></context:component-scan>
<!-- 开启切面注解 -->
<aop:aspectj-autoproxy/>
</beans> -
测试类
package com.alibaba.wlq.test; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; import com.alibaba.wlq.controller.UsersController;
import com.alibaba.wlq.invoke.Arithmetic;
import com.alibaba.wlq.invoke.ArithmeticImp; public class Test2 { public static void main(String[] args) {
// TODO Auto-generated method stub
ApplicationContext app = new ClassPathXmlApplicationContext("app3.xml");
Arithmetic arith = (Arithmetic) app.getBean("arithmeticImp");
arith.add(15.0, 20.0);
}
} -
打印结果
alibaba------>the method add begin with[15.0, 20.0]
35.0
alibaba------>the method *** end result
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使用xml配置文件
导入相应的jar包
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创建接口并且创建相应的类实现该接口
package com.alibaba.wlq.invoke; public interface Metic {
public double add(double a,double b);
public double sub(double a,double b);
public double mul(double a,double b);
public double div(double a,double b);
}package com.alibaba.wlq.invoke; public class MeticImp implements Metic{ @Override
public double add(double a, double b) {
double result = a + b;
System.out.println(result);
return result;
} @Override
public double sub(double a, double b) {
double result = a - b;
System.out.println(result);
return result;
} @Override
public double mul(double a, double b) {
double result = a * b;
System.out.println(result);
return result;
} @Override
public double div(double a, double b) {
double result = a / b;
System.out.println(result);
return result;
} } -
创建切面类
package com.alibaba.wlq.invoke; import java.util.Arrays; import org.aspectj.lang.JoinPoint; public class Invoke {
public void before(JoinPoint joinPoint) {
Object[] args = joinPoint.getArgs();
String name = joinPoint.getSignature().getName();
System.out.println("alibaba------>the method "+name+" begin with "+Arrays.asList(args));
}
public void after(JoinPoint joinPoint) {
String name = joinPoint.getSignature().getName();
System.out.println("alibaba------>the method "+name+" end result:");
}
public void afterreturn(Object result) {
System.out.println("result:========"+result);
}
} -
配置文件
<?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"
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-4.2.xsd"> <!-- 定义被通知的程序类 -->
<bean id="metic" class="com.alibaba.wlq.invoke.MeticImp"></bean> <!-- 定义切面类的Bean -->
<bean id="invoke" class="com.alibaba.wlq.invoke.Invoke"></bean> <!-- 配置切面 -->
<aop:config>
<!-- 定义表达式、切点 -->
<aop:pointcut expression="execution(* com.alibaba.wlq.invoke.*.*(..))" id="point"/>
<!-- 定义切面 -->
<aop:aspect ref="invoke">
<!-- 定义前置通知 -->
<aop:before method="before" pointcut-ref="point" />
<!-- 定义后置通知 -->
<aop:after method="after" pointcut-ref="point"/>
<!-- 定义返回通知returning属性值得名称要和方法中的参数名称一致 -->
<aop:after-returning method="afterreturn" pointcut-ref="point" returning="result"/>
</aop:aspect>
</aop:config>
</beans> -
测试类
package Test; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; import com.alibaba.wlq.invoke.Metic; public class Test1 {
public static void main(String[] args) {
ApplicationContext app = new ClassPathXmlApplicationContext("app.xml");
Metic arith = (Metic) app.getBean("metic");
arith.add(15, 10);
}
} -
输出结果
alibaba------>the method add begin with [15.0, 10.0]
25.0
alibaba------>the method add end result:
result:========25.0