jdk spi

 

代碼實現：

1定義接口

public interface TestService {
    Result<String> sayHello(String name);
}

 

2.實現接口

public class CarServiceImpl implements TestService {

    @Override
    public Result<String> sayHello(String name) {
        return Result.success("車：" + name);
    }
}

 

public class UserServiceImpl implements TestService {
    @Override
    public Result<String> sayHello(String name) {
        return Result.success("用戶" + name);
    }
}

 

3.

 

4.測試

public class Client {
    public static void main(String[] args) {
        ServiceLoader<TestService> loadedParsers = ServiceLoader.load(TestService.class);
        Iterator<TestService> iterator = loadedParsers.iterator();
        while (iterator.hasNext()){
            TestService testService = iterator.next();
            Result<String> re = testService.sayHello("你好");
            System.out.println(re);
        }
    }
}

Result(resultCode=200, message=success, datas=用戶你好)
Result(resultCode=200, message=success, datas=車：你好)

 

5.源碼解析

START

   

 
public static <S> ServiceLoader<S> load(Class<S> service) {
//獲取當前線程類加載器
        ClassLoader cl = Thread.currentThread().getContextClassLoader();
// service是當前對象，去load新 serviceloader
        return ServiceLoader.load(service, cl);
    }

 

while (iterator.hasNext()){