spring AOP 前置增强，后置增强小Demo

朱雀 2022-08-08 14:00 156阅读 0赞

# 服务员接口  Waiter.java #

package com.paic.zhangqi.spring.aop;
    
    public interface Waiter {
    	void greetTo(String name);
    	void serveTo(String name);
    }

# 服务员接口实现类  NaiveWaiter.java #

package com.paic.zhangqi.spring.aop;
    
    public class NaiveWaiter implements Waiter {
    
    	@Override
    	public void greetTo(String name) {
    		System.out.println("greet to "+name+"...");
    	}
    
    	@Override
    	public void serveTo(String name) {
    		System.out.println("serving "+name+"...");
    	}
    }

# 前置增强类  GreetingBeforeAdvice.java 在目标类方法执行前执行    #

package com.paic.zhangqi.spring.aop;
    
    import java.lang.reflect.Method;
    import org.springframework.aop.MethodBeforeAdvice;
    
    public class GreetingBeforeAdvice implements MethodBeforeAdvice {
    	
    	@Override
    	public void before(Method method, Object[] args, Object obj) throws Throwable {
    		String clientName = (String)args[0];
    		System.out.println("How are you！Mr."+clientName+".");
    	}
    }

# 后置增强类GreetingAfterAdvice.java 在目标类方法调用后执行    #

package com.paic.zhangqi.spring.aop;
    
    import java.lang.reflect.Method;
    import org.springframework.aop.AfterReturningAdvice;
    
    public class GreetingAfterAdvice implements AfterReturningAdvice {
    
    	@Override
    	public void afterReturning(Object arg0, Method arg1, Object[] arg2,
    			Object arg3) throws Throwable {
    		System.out.println("Please enjoy yourself!");
    	}
    }

# 测试类  TestAdvice.java #

package com.paic.zhangqi.spring.aop;
    
    import org.springframework.aop.AfterAdvice;
    import org.springframework.aop.BeforeAdvice;
    import org.springframework.aop.framework.ProxyFactory;
    
    public class TestAdvice {
    
    	public static void main(String[] args) {
    		
    		Waiter target = new NaiveWaiter();
    		
    		BeforeAdvice beforeAdvice = new GreetingBeforeAdvice();
    		AfterAdvice afterAdvice = new GreetingAfterAdvice();
    		
    		// spring 提供的代理工厂
    		ProxyFactory pf = new ProxyFactory();
    		
    		// 设置代理目标
    		pf.setTarget(target);
    		
    		// 为代理目标添加增强
    		pf.addAdvice(beforeAdvice);
    		pf.addAdvice(afterAdvice);
    		
    		// 生成代理实例
    		Waiter proxy = (Waiter)pf.getProxy();
    		
    		proxy.greetTo("John");
    		proxy.serveTo("Tomcat");
    
    	}
    }

输出结果

How are you！Mr.John.
    greet to John...
    Please enjoy yourself!
    How are you！Mr.Tomcat.
    serving Tomcat...
    Please enjoy yourself!

# 使用配置文件进行配置  beans.xml #

<?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:p="http://www.springframework.org/schema/p"
    	xsi:schemaLocation="http://www.springframework.org/schema/beans 
         http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    
    	<bean id="greetingBefore" class="com.paic.zhangqi.spring.aop.GreetingBeforeAdvice" />
    	
    	<bean id="greetingAfter" class="com.paic.zhangqi.spring.aop.GreetingAfterAdvice" />
    	
    	<bean id="target" class="com.paic.zhangqi.spring.aop.NaiveWaiter" />
    	
    	<bean id="waiter" class="org.springframework.aop.framework.ProxyFactoryBean">
    		<property name="proxyInterfaces" value="com.paic.zhangqi.spring.aop.Waiter" />
    		<property name="interceptorNames" value="greetingBefore,greetingAfter" />
    		<property name="target" ref="target" />
    	</bean>
    	
    </beans>

# 对应的测试类 SpringConfigTest.java #

package com.paic.zhangqi.spring.aop;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class SpringConfigTest {
    
    	public static void main(String[] args) {
    		String configPath = "com/paic/zhangqi/spring/aop/beans.xml";
    		ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
    		Waiter waiter = (Waiter) ctx.getBean("waiter");
    		waiter.greetTo("John");
    		waiter.serveTo("Tomcat");
    	}
    }

同样得到输出

How are you！Mr.John.
    greet to John...
    Please enjoy yourself!
    How are you！Mr.Tomcat.
    serving Tomcat...
    Please enjoy yourself!