Simple email validation [duplicate]

问题

Possible Duplicate:
Verify email in Java

I'm trying to do a very simple email validation. But the problem is when I try something like tom@@@@gmail.com it returns true.

Here are the codes:

public static boolean validateEmail(String email){
        boolean isValidEmail = false;
       // Input the string for validation
       // String email = "xyz@.com";
       // Set the email pattern string
       Pattern p = Pattern.compile(".+@.+\\.[a-z]+");

       // Match the given string with the pattern
       Matcher m = p.matcher(email);

       // check whether match is found
       boolean matchFound = m.matches();

       StringTokenizer st = new StringTokenizer(email, ".");
       String lastToken = null;
       while (st.hasMoreTokens()) {
          lastToken = st.nextToken();
       }

       if (matchFound && lastToken.length() >= 2
          && email.length() - 1 != lastToken.length()) {


          // validate the country code
          isValidEmail = true;
       }
       else isValidEmail = false;

    return isValidEmail;
}

Please help. Thanks in advance.

回答1:

.+@.+ will match anything, including @, followed by @, followed by anything, including @. Use [^@]+@[^@]+ instead.

Or cease from reinventing the wheel, grab Apache Commons and use its EmailValidator.

回答2:

You can use the class javax.mail.internet.InternetAddress from the Javamail API (there is a validate method)

回答3:

This is a solved problem in numerous libraries. Do not reimplement your own.

Getting this 100% correct in regexps is much, much harder than you think it is.

回答4:

This site suggests that the following pattern matches RFC 5322 and covers most email addresses used today:

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

It worked for a few quick tests that I made.

Consider storing the compiled pattern in a constant for improved performance.

回答5:

It should be Pattern p = Pattern.compile(".+@{1}+\\.[a-z]+");

BUT:

This my answer above is wrong exactly like the answer @larsmans, because:

this(comment)me@demo.com is a valid email.

You have to read the RFC: http://tools.ietf.org/html/rfc5322

In fact, use a good library, as apache-commons.

来源：https://stackoverflow.com/questions/8259790/simple-email-validation

标签

java

regex

email-validation