
有两个人,张三和李四
package com.su.service; public class ZhangSan implements Tester{ public void test(){
System.out.println("张三-测试程序");
}
}
package com.su.service; public class Lisi implements Tester{ public void test(){
System.out.println("李四-测试程序");
}
}
有一个Tester接口,张三和李四都实现了这个接口
package com.su.service; public interface Tester {
public void test();
}
测试工作类
package com.su.service; public class JavaWork { private Tester tester; public void setTester(Tester tester) {
this.tester = tester;
} public void doTest(){
// ZhangSan zhangsan=new ZhangSan();
// zhangsan.test();
tester.test();
}
}
主管负责分配谁去测试(通过setTester,即控制权交给主管,而非每次换人去测试,都要在JavaWork的doTest类中new出人,这就是控制反转)
package com.su.test; import com.su.service.JavaWork;
import com.su.service.Lisi; public class Test {
/**
* 主管执行命令
*/
public static void main(String[] args) {
JavaWork javaWork=new JavaWork();
// javaWork.setTester(new ZhangSan());
javaWork.setTester(new Lisi());
javaWork.doTest();
}
}
而spring帮助我们做的就是这个,在xml文件中通过配置(spring管理bean),分配测试人员
<?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="zhangsan" class="com.su.service.ZhangSan"></bean> <bean id="lisi" class="com.su.service.Lisi"></bean> <bean id="javaWork" class="com.su.service.JavaWork">
<property name="tester" ref="lisi"></property>
</bean> </beans>
package com.su.test; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; import com.su.service.JavaWork; public class Test2 {
public static void main(String[] args) {
ApplicationContext ac=new ClassPathXmlApplicationContext("beans.xml");
JavaWork javaWork=(JavaWork)ac.getBean("javaWork");
javaWork.doTest();
}
}