《判断字符串是否在字符串中，取想要的字符串》

NSString *strttt = @"http://source.hahaha66.cn/1615946279.png";
    if ([strttt localizedCaseInsensitiveContainsString:@"cn/"])
    {
        if ([strttt localizedCaseInsensitiveContainsString:@".png"])
        {
            NSRange startRange = [strttt rangeOfString:@"cn/"];
            NSRange endRange = [strttt rangeOfString:@".png"];
            NSRange range = NSMakeRange(startRange.location + startRange.length, endRange.location - startRange.location - startRange.length);
            NSString *result = [strttt substringWithRange:range];
            XPFLog(@" ===== %@ ", result);
        }
    }
    else
    {
        XPFLog(@" 失败 ");
    }