转：http://blog.csdn.net/dotnet25/article/details/8331959
字符串：var s = "1,2,3,4,5,"
目标：删除最后一个 ","
方法：
s=s.substring(0,s.Length-1)；
字符串：var s2 = "img/upload/123.jpg"
目标：获取文件名(不包含后缀名)
方法：
s2=s2.substring(s2.lastIndexOf(‘/‘)+1,
s2.lastIndexOf(‘.‘));原文：http://www.cnblogs.com/guxingzhe/p/5366682.html