基于SUN的javacomm20-win32 API中的例子SerialDemo改进，实现回车发送，可接收中文。 类库使用更适用现在系统的rxtx-2.1-7。-Based on SUN' s javacomm20-win32 API to improve the SerialDemo example, to achieve Enter to send, can receive the Chinese. Library System is now more suitable for t