抛 Exception吧

Exceptions should be thrown when the contract between a method and its caller cannot be fulfilled. This is the usage identified in the Java™ Language Specification.

抛出异常不是严格禁止的事情，如果在项目结构中需要处理“函数分内的事情”则不需要抛出异常如果是“分外”的事情，则需要抛出异常。