程序路径包为：com.spring.kinghts（kinght单词拼写错误，怕麻烦就没有重构）
package com.spring.kinghts;
public interface Knight {
public void doWhat();
}
package com.spring.kinghts;
public interface ToDo {
public void toDo();
}
package com.spring.kinghts;
public class Knight_guanyu implements Knight{
private ToDo todo;
public Knight_guanyu(ToDo todo){
this.todo=todo;
}
@Override
public void doWhat() {
todo.toDo();
}
}
关羽类的构造器中传入了ToDo接口引用对象，目的是为了实现依赖构造三种方法中其一（构造器依赖），以降低耦合度。
package com.spring.kinghts;
public class ToDo_guanyu_drink implements ToDo{
@Override
public void toDo() {
System.out.println("我可以喝酒");
}
}
<?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"> <bean id="knight" class="com.spring.kinghts.Knight_guanyu"> <constructor-arg ref="todo"/> </bean> <bean id="todo" class="com.spring.kinghts.ToDo_guanyu_drink"> </bean> </beans>
第一个<bean>中，注入了Knight_guanyu bean，第二个<bean>中，创建ToDo_guanyu_drink bean。在这里，Knight_guanyu bean在构造的时候传入了ToDo_guanyu_drink bean的引用。
package com.spring.kinghts;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class KnightMain {
public static void main(String[] args) throws Exception{
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
Knight_guanyu obj=(Knight_guanyu) context.getBean(Knight.class);
obj.doWhat();
}
}
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");作用是加载Spring上下文
Knight_guanyu obj=(Knight_guanyu) context.getBean(Knight.class);作用是获取knight bean
obj.doWhat();作用是使用knight
热爱分享拒绝拿来主义，博客精神永存——cvrigo
2016-11-07 23:24:37
原文：http://www.cnblogs.com/cvirgo/p/6041113.html