数字保留前四位后四位中间用* 代替

+ (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;

    

}