## 使用说明

```kotlin
interface IHello {
    fun hello()
}

@RegisterService(value = IHello::class)
class AHello : IHello {
    override fun hello() {
        Log.d("Hello", "AHello")
    }
}

//key用来区分不同的实现，默认key是"default"，不能定义多个相同key
@RegisterService(value = IHello::class, key = "key_b_hello")
class BHello : IHello {
    override fun hello() {
        Log.d("Hello", "BHello")
    }
}

fun hello() {
    ServiceLoader.get(IHello::class.java)?.hello() //AHello key是"default", 所以这里调用AHello
    ServiceLoader.get(IHello::class.java, "key_b_hello")?.hello() //BHello key是"key_b_hello", 所以这里调用BHello
}
```