+ (NSString *)bankNumber:(NSString *)number
{
if (number == nil) {
return nil;
}
NSString *str = @"****";
NSString *starStrNumber = [number substringToIndex:4];
NSString *endStrNumber = [number substringFromIndex:number.length - 4];
NSString *strs = [[starStrNumber stringByAppendingString:str] stringByAppendingString:endStrNumber];
number = strs;
return number;
}