Java的SPI机制

1.案例代码

public class SPIDemo {
    public static void main(String[] args) {
        ServiceLoader<RunInterface> load = ServiceLoader.load(RunInterface.class);

        Iterator<RunInterface> iterator = load.iterator();

        while (iterator.hasNext()) {
            RunInterface runInterface = iterator.next();
            runInterface.run();
        }
        
    }
}

接口

public interface RunInterface {
    void run();
}

实现类

public class Car implements RunInterface {
    @Override
    public void run() {
        System.out.println("小汽车四个轮跑");
    }
}

public class Human implements RunInterface {
    @Override
    public void run() {
        System.out.println("人类两条腿跑");
    }
}

resource目录下新建META-INF/META-INF/services文件夹

文件夹下新建文件，文件名为需要调用的接口名的全限定类名

2.源码跟进

2.1 实例化ServiceLoader与LazyIterator

ServiceLoader.load(Class service）；