如何验证电子邮件地址

Question

我试试这个例子，但它有一些电子邮件类型没有检查。

- (BOOL) validateEmail: (NSString *) candidate {
    NSString *emailRegex =
@"(?:[a-z0-9!#$%\\&'*+/=?\\^_`{|}~-]+(?:\\.[a-z0-9!#$%\\&'*+/=?\\^_`{|}"
@"~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\"
@"x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-"
@"z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5"
@"]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-"
@"9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21"
@"-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])"; 
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES[c] %@", emailRegex]; 

    return [emailTest evaluateWithObject:candidate];
}

此示例不检查类型为 email@domain.c-om,email@domain.c#omc ,email@11.160.58.260 , em#il@domain.com 的电子邮件地址。检查电子邮件地址避免这种类型的正确方法是什么？

Answer 1

你从哪里得到的正则表达式？看起来你是从 http://www.regular-expressions.info/email.html 那里得到的，上面写着

你可以（但你不应该——继续阅读）用这个常规实现它 表达

然后它说

你不应该使用这个正则表达式的原因是它只检查 电子邮件地址的基本语法。 john@aol.com.nospam 将是 根据 RFC 5322 被视为有效的电子邮件地址。

然后那个页面建议使用

[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?

对于 Objective-C，您必须避开反斜杠，然后一切就绪。

Answer 2

类别添加方法isEmail

 -(BOOL)isEmail {
    BOOL stricterFilter = YES; 
    NSString *stricterFilterString = @"^[_A-Za-z0-9-+]+(\\.[_A-Za-z0-9-+]+)*@[A-Za-z0-9-]+(\\.  [A-Za-z0-9-]+)*(\\.[A-Za-z‌​]{2,4})$";
    NSString *laxString = @".+@([A-Za-z0-9]+\\.)+[A-Za-z]{2}[A-Za-z]*";
    NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
    return [emailTest evaluateWithObject:self];
}

调用这个方法

if([text isEmail]){
//validate email id
}else{
//not email id
}

Disscusion for Email Validation

Answer 3

试试这个：

+ (BOOL)validateEmail:(NSString *)candidate
{
    NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
    return [emailTest evaluateWithObject:candidate];
}

Answer 4

试试这个代码来验证给定的字符串是否是电子邮件。

- (BOOL)validEmail:(NSString *) emailString
{
    if([emailString length]==0)
    {
        return NO;
    }
    NSString *regExPattern = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
    NSRegularExpression *regEx = [[NSRegularExpression alloc] initWithPattern:regExPattern options:NSRegularExpressionCaseInsensitive error:nil];
    NSUInteger regExMatches = [regEx numberOfMatchesInString:emailString options:0 range:NSMakeRange(0, [emailString length])];

    if (regExMatches == 0)
    {
        return NO;
    }
    else
    {
        return YES;
    }
}

Answer 5

+(BOOL)validEmailid:(NSString *)emailId{

 @try

  {

   BOOL stricterFilter = NO;

    NSString *stricterFilterString = @"[A-Z0-9a-z\\._%+-]+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}";

    NSString *laxString = @".+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2}[A-Za-z]*";

    NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;

    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

    if ([emailTest evaluateWithObject:emailId]){
        return YES;
    }
    else{
        [self showalertwithmessage:@"Invalid emailid"];

        return NO;
    }

}
@catch (NSException *exception)
{
    NSLog(@"Error occurred in in Utils::stringIsValidEmail : %@",[exception description]);
}

}