public interface KeyGenerator {
/**
* Generate a key for the given method and its parameters.
* @param target the target instance
* @param method the method being called
* @param params the method parameters (with any var-args expanded)
* @return a generated key
*/
Object generate(Object target, Method method, Object... params);
}
如以上的Java接口,Java中的可变参数是以...出现,而Scala则不同,Scala的可变参数是以*出现的,如下:
def generate(target:Object, method: Method, params: Object*): Object = {
//省略
}
如果你使用IDE自动生成的方法参数如下:
def generate(target:Any, method: Method, params: Array[AnyRef]): Object = {
//省略
}
在使用Scala重写了KeyGenerator接口的generate方法时编译器总是无法通过,即在Scala中使用params: Object或者是Array[AnyRef]是无法替代Object... params的,注意Scala中的Any和AnyRef都是Object类型,classOf[Any]和classOf[AnyRef]都是Object类型,解决办法是你只需要将Array[AnyRef]修改成AnyRef就可以编译通过了。
def wiselyKeyGenerator(): KeyGenerator = {
new KeyGenerator() {
override protected def generate(target: Any, method: Method, params: AnyRef*): Object = {
var sb = new StringBuilder()
sb.append(target.getClass().getName())
sb.append(method.getName())
for(param <- params) {
sb.append(param.toString())
}
sb.toString()
}
};
}