字符串转NSDate 格式
http://www.2cto.com/kf/201407/320341.html
//设置时间格式
//根据字符串转换成一种时间格式 供下面解析
NSString* string = ValueModel.addTime;
NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init];
[inputFormatter setDateFormat:@"yyyyMMddHHmmss"];
NSDate* inputDate = [inputFormatter dateFromString:string];
NSDateFormatter*outputFormatter = [[NSDateFormatter alloc] init];
[outputFormatter setDateFormat:@"yyyy年MM月dd日 HH:mm"];
NSString* strResult = [outputFormatter stringFromDate:inputDate];