DNS规定，域名中的标号都由英文字母和数字组成，每一个标号不超过63个字符，也不区分大小写字母。标号中除连字符（-）外不能使用其他的标点符号。级别最低的域名写在最左边，而级别最高的域名写在最右边。由多个标号组成的完整域名总共不超过255个字符。
由此匹配完整域名的正则表达式：
^(?=^.{3,255}$)[a-zA-Z0-9][-a-zA-Z0-9]{0,62}(.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+$
例如：baidu.com
匹配网址：
^(?=^.{3,255}$)(http(s)?://)?(www.)?[a-zA-Z0-9][-a-zA-Z0-9]{0,62}(.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+(:d+)*(/w+.w+)*$
例如： http://www.baidu.com
匹配http url：
^(?=^.{3,255}$)(http(s)?://)?(www.)?[a-zA-Z0-9][-a-zA-Z0-9]{0,62}(.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+(:d+)*(/w+.w+)*([?&]w+=w*)*$
例如： http://www.tetet.com/index.html?q=1&m=test
项目中WKWebView使用：
WKWebView *_detailWebView; //识别二维码跳转;不是链接显示内容点击网址跳转 if ([self.m_url hasPrefix:@"http"]) { // NSString *urlStr = [self.m_url stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]]; // 解决url包含中文不能编码的问题 NSString *urlStr = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,(CFStringRef)self.m_url,(CFStringRef)@"!$&'()*+,-./:;=?@_~%#[]",NULL,kCFStringEncodingUTF8)); NSURL *url = [NSURL URLWithString:urlStr]; NSMutableURLRequest *request =[NSMutableURLRequest requestWithURL:url]; [request setHTTPShouldHandleCookies:YES]; [_detailWebView loadRequest:request]; } else { self.topTitleLabel.text = @"扫描结果"; QRCodeLabel = [[ZXLabel alloc]initWithFrame:CGRectMake(10, 10, SCREENWIDTH-20, 50) fontSize:16 text:@"" textColor:[UIColor colorWithHexString:@"#000000"] textAlignment:NSTextAlignmentLeft numberOfLines:0]; [_detailWebView addSubview:QRCodeLabel]; if ([self urlValidation:[NSString stringWithFormat:@"%@",self.m_url]]==YES) {//网址 [self textColour]; QRurlStr = [NSString stringWithFormat:@"http://%@",[NSString stringWithFormat:@"%@",self.m_url]]; } else { // 文字html可拷贝，查询 QRurlStr = [NSString stringWithFormat:@"<html><head><meta http-equiv='Content-Type' content='text/html; charset=utf-8'><meta name='viewport' content='width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no'><style>*{margin:5px;padding:0px;}</style><title></title></head<body>%@</body></html>",[NSString stringWithFormat:@"%@",self.m_url]]; [_detailWebView loadHTMLString:QRurlStr baseURL:Nil]; } } #pragma mark -- 识别图中二维码 /** * 网址正则验证 * * @param string 要验证的字符串 * * @return 返回值类型为BOOL */ - (BOOL)urlValidation:(NSString *)string { NSError *error; NSString *regulaStr = @"((http[s]{0,1}|ftp)://[a-zA-Z0-9\.\-]+\.([a-zA-Z]{2,4})(:\d+)?(/[a-zA-Z0-9\.\-~!@#$%^&*+?:_/=<>]*)?)|(www.[a-zA-Z0-9\.\-]+\.([a-zA-Z]{2,4})(:\d+)?(/[a-zA-Z0-9\.\-~!@#$%^&*+?:_/=<>]*)?)|^(?=^.{3,255}$)[a-zA-Z0-9][-a-zA-Z0-9]{0,62}(\.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+$"; NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regulaStr options:NSRegularExpressionCaseInsensitive error:&error]; NSArray *arrayOfAllMatches = [regex matchesInString:string options:0 range:NSMakeRange(0, [string length])]; for (NSTextCheckingResult *match in arrayOfAllMatches){ NSString* substringForMatch = [string substringWithRange:match.range]; NSLog(@"匹配--%@",substringForMatch); return YES; } return NO; } - (void)textColour { NSMutableAttributedString *abs = [[NSMutableAttributedString alloc]initWithString:[NSString stringWithFormat:@"%@",self.m_url]]; [abs beginEditing]; //字体大小 // [abs addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:20.0] range:NSMakeRange(0, 2)]; //字体颜色 [abs addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(0,[NSString stringWithFormat:@"%@",self.m_url].length)]; //下划线 [abs addAttribute:NSUnderlineStyleAttributeName value:@(NSUnderlineStyleSingle) range:NSMakeRange(0,[NSString stringWithFormat:@"%@",self.m_url].length)]; QRCodeLabel.attributedText = abs; UITapGestureRecognizer *LabelTap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(capchaBtn:)]; QRCodeLabel.userInteractionEnabled = YES; [QRCodeLabel addGestureRecognizer:LabelTap]; } // 链接跳转 - (void)capchaBtn:(UITapGestureRecognizer *)sendr{ NSLog(@"跳转网页~~"); [QRCodeLabel removeFromSuperview]; //NSString *urlStr = [QRurlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; NSString *urlStr = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,(CFStringRef)QRurlStr,(CFStringRef)@"!$&'()*+,-./:;=?@_~%#[]",NULL,kCFStringEncodingUTF8)); NSURL *url =[NSURL URLWithString:urlStr]; NSMutableURLRequest *request =[NSMutableURLRequest requestWithURL:url]; [request setHTTPShouldHandleCookies:YES]; [_detailWebView loadRequest:request]; }