java中的SPI机制

"1.0" encoding="UTF-8"?>
"http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    4.0.0com.zy
    java-spi-demo
    1.0-SNAPSHOTjunit
            junit
            RELEASEcompile

package com.zy;

public interface SpiServiceI {

    void sayHello(String s);
}

package com.zy;

public class SpiServiceEnglishImpl implements SpiServiceI {
    @Override
    public void sayHello(String s) {
        System.out.println(s+": hello world");
    }
}

package com.zy;

public class SpiServiceChinaImpl implements SpiServiceI {
    @Override
    public void sayHello(String s) {
        System.out.println(s+": 你好,世界");
    }
}

package com.zy;

import org.junit.Test;
import java.util.Iterator;
import java.util.ServiceLoader;

public class SpiTest {

    @Test
    public void fn(){
　　　　 // 通过ServiceLoader.load(Class class); 来动态加载Service的实现类
        ServiceLoader serviceLoader = ServiceLoader.load(SpiServiceI.class);
        Iterator iterator = serviceLoader.iterator();
        while(iterator != null  && iterator.hasNext()){
            SpiServiceI serviceI = iterator.next();
            serviceI.sayHello("tom");
        }
    }
}