说明：  JNA（Java Native Access ）提供一组Java工具类用于在运行期动态访问系统本地库（native library：如Window的dll）而不需要编写任何Native/JNI代码。开发人员只要在一个java接口中描述目标native library的函数与结构，JNA将自动实现Java接口到native function的映射。
(JNA (Java Native Access) provides a set of Java tools for the dynamic run-time access to the system of local libraries (native library: such as the Window of the dll) without the need for the preparation of any Native/JNI code. As long as developers in a java interface as described in the target native library function and structure, JNA will automatically realize Java interface to native function mapping.)