一、目标
要在BraveKnight调用embarkOnQuest()前后各做一些处理(调用Minstrel的方法)
二、
1.minstrel.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <beans xmlns="http://www.springframework.org/schema/beans" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xmlns:aop="http://www.springframework.org/schema/aop" 5 xsi:schemaLocation="http://www.springframework.org/schema/aop 6 http://www.springframework.org/schema/aop/spring-aop.xsd 7 http://www.springframework.org/schema/beans 8 http://www.springframework.org/schema/beans/spring-beans.xsd"> 9 10 <bean id="knight" class="chapter01.sia.knights.BraveKnight"> 11 <constructor-arg ref="quest" /> 12 </bean> 13 14 <bean id="quest" class="chapter01.sia.knights.SlayDragonQuest"> 15 <constructor-arg value="#{T(System).out}" /> 16 </bean> 17 18 <bean id="minstrel" class="chapter01.sia.knights.Minstrel"> 19 <constructor-arg value="#{T(System).out}" /> 20 </bean> 21 22 <aop:config> 23 <aop:aspect ref="minstrel"> 24 <aop:pointcut id="embark" 25 expression="execution(* *.embarkOnQuest(..))"/> 26 27 <aop:before pointcut-ref="embark" 28 method="singBeforeQuest"/> 29 30 <aop:after pointcut-ref="embark" 31 method="singAfterQuest"/> 32 </aop:aspect> 33 </aop:config> 34 35 </beans>
分析：
(1)首先声明xsi:schemaLocation="http://www.springframework.org/schema/aop
(2)把Minstrel.java声明为bean，给spring管理
(3)声明<aop:config><aop:aspect，指定到ref="minstrel"
(4)声明<aop:pointcut，指定在这些方法中aop,expression="execution(* *.embarkOnQuest(..))"
(5)声明<aop:before、<aop:after
2.Minstrel
1 package chapter01.sia.knights; 2 3 import java.io.PrintStream; 4 5 public class Minstrel { 6 7 private PrintStream stream; 8 9 public Minstrel(PrintStream stream) { 10 this.stream = stream; 11 } 12 13 public void singBeforeQuest() { 14 stream.println("Fa la la, the knight is so brave!"); 15 } 16 17 public void singAfterQuest() { 18 stream.println("Tee hee hee, the brave knight " + 19 "did embark on a quest!"); 20 } 21 22 }
3.KnightMain
1 public class KnightMain { 2 3 public static void main(String[] args) throws Exception { 4 //ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:knight.xml"); 5 ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:minstrel.xml"); 6 Knight knight = context.getBean(Knight.class); 7 knight.embarkOnQuest(); 8 context.close(); 9 } 10 11 }
4.运行结果
1 三月 01, 2016 10:49:57 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 2 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3f3471d: startup date [Tue Mar 01 10:49:57 CST 2016]; root of context hierarchy 3 三月 01, 2016 10:49:57 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 4 信息: Loading XML bean definitions from class path resource [minstrel.xml] 5 Fa la la, the knight is so brave! 6 Embarking on quest to slay the dragon! 7 Tee hee hee, the brave knight did embark on a quest! 8 三月 01, 2016 10:49:58 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose 9 信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@3f3471d: startup date [Tue Mar 01 10:49:57 CST 2016]; root of context hierarchy