spi 介绍

1，定义接口

public interface Logger {
    void info();
}

2，定义实现类

public class Logback implements Logger {
    @Override
    public void info() {
        System.out.println("lockback print info");
    }
}

public class Log4j implements Logger {
    @Override
    public void info() {
        System.out.println("Log4j print info--");
    }
}

3，创建 在resources 目录下 创建META-INF\services\com.ky.kfk.spi.Logger配置

com.ky.kfk.spi.Log4j

4，测试类

import java.util.ServiceLoader;

public class Main {
    public static void main(String[] args) {
        ServiceLoader<Logger> logs = ServiceLoader.load(Logger.class);
        for (Logger logger : logs) {
            logger.info();
        }
    }
}