说明：  php对excel文件进行循环读取 php对字符进行ascii编码转化，将字符转为十进制数 php对excel日期格式读取，并进行显示转化 php对汉字乱码进行编码转化
(PHP cycle to read the excel file PHP the characters ASCII code conversion, the character to a decimal number PHP on Excel date format to read, and display transformation PHP on Chinese characters garbled code conversion)