springAop 环绕通知MethodInterceptor实现对结果进行缓存的计算器

Aop原理

SpringAop 原理就是动态代理

对于实现接口的目标类使用的是jdk动态代理

对于没有实现任何接口的目标类,使用的是cglib的动态代理

代理类是程序在运行期间由JVM根据反射等机制动态生成的自动生成代理类和代理对象。

所谓动态就是指在程序运行前不存在代理类的字节码文件。

SpringAop的配置方式

三种配置方式

一：SpringAop1.x 使用ProxyFactoryBean手动配置

二：SpringAop2.x 基于命名控件的配置

三：Annotation 基于注解的配置(推荐)

Advice类型

SpringAop支持五种类型的通知(增强)

注意：多个Advice之间不允许有耦合，即多个Advice之间不允许有业务交叉。

(1):SpringAop1.x 使用ProxyFactoryBean 手动代理

配置方式:

基本用法: 添加jar包

 <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <!--ioc01-core-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
        </dependency>
        <!--ioc01-bean-->
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
        </dependency>
        <!--ioc01-context-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </dependency>
        <!--ioc01-expression-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
        </dependency>
        <!--Aop依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
        </dependency>
        <!--cglib技术-->
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
        </dependency>

1:配置Advice通知

1定义增强类，实现相应的接口

package springaop06.advice;

import org.aopalliance.intercept.Joinpoint;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;

/**
 * package_name:springaop06.advice
 *
 * @author:徐亚远 Date:2020/2/20 13:22
 * 项目名:springDemo01
 * Description:TODO
 * Version: 1.0
 **/

public class CacheAdvice implements MethodInterceptor {
    //定义一个缓存
    Map<Key, Object> cache = new HashMap<>();

    /**
     * Implement this method to perform extra treatments before and
     * after the invocation. Polite implementations would certainly
     * like to invoke {@link Joinpoint#proceed()}.
     *
     * @param invocation the method invocation joinpoint
     * @return the result of the call to {@link Joinpoint#proceed()};
     * might be intercepted by the interceptor
     * @throws Throwable if the interceptors or the target object
     *                   throws an exception
     */
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        Method method = invocation.getMethod();
        Object[] args = invocation.getArguments();
        Object target = invocation.getThis();
        Key key = new Key();
        key.setMethod(method);
        key.setArgs(args);
        key.setTarget(target);
        //判断是否执行过这个方法
        if (cache.containsKey(key)) {
            //如果执行过直接返回值
            return cache.get(key);
        }
        System.out.println("methodName:"+method.getName()+" "+"args:"+Arrays.toString(args)+" "+"target"+target);
        Object proceed = invocation.proceed();
        //如果没有执行过这个方法把它加入到缓存中将结果加入到缓存中
        cache.put(key, proceed);
        return proceed;
    }
}

自定义Key

package springaop06.advice;

import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Objects;

/**
 * package_name:springaop06.key
 *
 * @author:徐亚远 Date:2020/2/20 13:42
 * 项目名:springDemo01
 * Description:自定义Key,判断方法是否被执行过的三要素:method args target
 * Version: 1.0
 **/

public class Key {
    private Method method;
    private Object[] args;
    private Object target;

    //判断Key的唯一性重写hashCode()和equals()方法
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Key key = (Key) o;
        return Objects.equals(method, key.method) &&
                Arrays.equals(args, key.args) &&
                Objects.equals(target, key.target);
    }

    @Override
    public int hashCode() {

        int result = Objects.hash(method, target);
        result = 31 * result + Arrays.hashCode(args);
        return result;
    }

    public Method getMethod() {
        return method;
    }

    public void setMethod(Method method) {
        this.method = method;
    }

    public Object[] getArgs() {
        return args;
    }

    public void setArgs(Object[] args) {
        this.args = args;
    }

    public Object getTarget() {
        return target;
    }

    public void setTarget(Object target) {
        this.target = target;
    }
}

对结果计算的接口

package springaop06.service;


/**
 * package_name:springaop06.service
 *
 * @author:徐亚远 Date:2020/2/20 13:26
 * 项目名:springDemo01
 * Description:TODO
 * Version: 1.0
 **/
public interface CacheService {
    int add(int a,int b);
    double del(int a,int b);
}

对结果进行计算的实现类

package springaop06.service.impl;

import springaop06.service.CacheService;

/**
 * package_name:springaop06.service.impl
 *
 * @author:徐亚远 Date:2020/2/20 13:27
 * 项目名:springDemo01
 * Description:TODO
 * Version: 1.0
 **/

public class CacheServiceImpl implements CacheService {
    @Override
    public int add(int a, int b) {
        System.out.println("cacheServiceImpl  add();");
        return a+b;
    }

    @Override
    public double del(int a, int b) {
        System.out.println("cacheServiceImpl  del()");
        return a-b;
    }
}

配置spring.xml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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <!--springaop 1.x配置-->
    <!--目标类实例-->
    <bean id="cacheServiceTarget" class="springaop06.service.impl.CacheServiceImpl"/>

    <!--配置通知-->
    <bean id="cacheAdvice" class="springaop06.advice.CacheAdvice"/>

    <!--配置advisor-->
    <bean id="cacheAdvisor" class="org.springframework.aop.support.NameMatchMethodPointcutAdvisor">
        <!--配置通知-->
        <property name="advice" ref="cacheAdvice"/>
        <!--配置切点-->
        <property name="mappedNames">
            <list>
                <value>add</value>
                <value>del</value>
            </list>
        </property>
    </bean>
    <!--配置代理-->
    <bean id="cacheService" class="org.springframework.aop.framework.ProxyFactoryBean">
        <!--配置目标类实例-->
        <property name="target" ref="cacheServiceTarget"/>
        <!--配置目标实例接口列表-->
        <property name="interfaces">
            <list>
                <value>springaop06.service.CacheService</value>
            </list>
        </property>
        <!--配置交叉业务-->
        <property name="interceptorNames">
            <list>
                <value>cacheAdvisor</value>
            </list>
        </property>
    </bean>
</beans>

书写测试类

package springaop06.controller;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import springaop06.service.CacheService;

/**
 * package_name:springaop06.controller
 *
 * @author:徐亚远 Date:2020/2/20 13:23
 * 项目名:springDemo01
 * Description:TODO
 * Version: 1.0
 **/

public class CacheTest {
    public static void main(String [] args){
        ApplicationContext ac = new ClassPathXmlApplicationContext("aop06/spring.xml");
      CacheService cacheService = (CacheService) ac.getBean("cacheService");
        System.out.println(cacheService.add(2,4 ));
        System.out.println(cacheService.add(2,4 ));
        System.out.println(cacheService.add(4,2 ));
        System.out.println(cacheService.add(4,4 ));
        System.out.println("=========================");
        System.out.println(cacheService.del(4,5 ));
        System.out.println(cacheService.del(4,5 ));
        System.out.println(cacheService.del(5,5 ));
        System.out.println(cacheService.del(5,6 ));
      System.out.println(cacheService.getClass());
    }
}

测试结果如图：