iOS处理服务器返回的金额的时候，有时候会有类似0.0100，有时候会有类似8.80000001样子，有时候传销7.9999999的时候。其实是iOS平台的解析的问题。
两种方法
1.NSString的一个类别方法

/** 字符串小数格式化 
@return 小数字符串 */
- (NSString *)decimalNumberString {      

 NSString *numberString = [NSString stringWithFormat:@"%lf",[self doubleValue]];   
 return [NSString stringWithFormat:@"%@",[NSDecimalNumber decimalNumberWithString:numberString]];
}

2.转化一下

-(NSString *)stringByYouWantWithOriginString:(NSString *)originString{
    NSString *MM = @"";
    if ([originString containsString:@"."]) {
        NSArray *array_XString = [originString componentsSeparatedByString:@"."];
        NSString *string_XLast = array_XString.lastObject;
        if (string_XLast.length == 1 ) {
            MM = [NSString stringWithFormat:@"%.1f",[originString floatValue]];
        }else if (string_XLast.length >=2){
            MM = [NSString stringWithFormat:@"%.2f",[originString floatValue]];
        }
        if (string_XLast.length >=2){
            if ([MM hasSuffix:@"00"]) {
                MM = [NSString stringWithFormat:@"%.0f" , [MM floatValue]];
            }else if ([MM hasSuffix:@"0"]){
                MM = [NSString stringWithFormat:@"%.1f" , [MM floatValue]];
            }
        }else if (string_XLast.length ==1 ){
            if ([MM hasSuffix:@"0"]) {
                MM =[NSString stringWithFormat:@"%.0f" , [MM floatValue]];
            }
        }
    }else{
        MM =originString;
    }
    if ([MM hasSuffix:@".00"]) {
        MM = [NSString stringWithFormat:@"%.0f",[MM floatValue]];
    }
    return MM;
}