对字符串进行 URL编码解码，有些程序比如关于internet 客户端程序或者是 跟WEB页面交互的程序需要将字符串进行URL编码然后才能发送等，可以用此程序里的相关函数进行封装。-In a URL coding and decoding, some programs such as Internet client program or with WEB page is interactive program need to will character string coding and th