Validating Email Field

Question

Hi
I am developing a form in which there is an email field which i have to enter in a textArea.
tell me how can i check whether the entered email id is valid or not.
Its urgent
Thanks in advance
Dhiraj

Answer 1

In case you are using JDK version prior to 1.4 you can use following function.
<pre>
* Validates the structure of the Email Address. This method covers most
* requirements of the RFC822 specification.
* @param strEmailAddress Email Address to be validated
* @return true if validation is successful, false otherwise
* @see RFC822
* @see * Online Email Validator
public static boolean isValidEmailAddress(String strEmailAddress)
          boolean bValid = true;
          // return false if strEmailAddress is either null or empty
          if (isNullorEmpty(strEmailAddress)) {
               return false;
          // calculate length of the email address
          int iLength = strEmailAddress.length();
          // get the first occurrence of @ char
          int iCharAtPosition = strEmailAddress.indexOf("@");
          // validation fails if @ character is not present
if (iCharAtPosition == -1) {
     bValid = false;
          // validation fails if @ character found is in the first or last position
else if ((iCharAtPosition == 0) || (iCharAtPosition == (iLength - 1))) {
     bValid = false;
          // validation fails if more than 1 @ character are present
else if (strEmailAddress.indexOf("@", iCharAtPosition + 1) > -1) {
bValid = false;
          else {
               // traverse thru all the characters in the given email address
     for (int i = 0; i < iLength; i++) {
          // get the character at the i position
     char c = strEmailAddress.charAt(i);
     if (c == '.') {
                         // validation fails if . character found is in the first or last position
          if ((i == 0) || (i == (iLength - 1))) {
          bValid = false;
          break;
     // . character cannot come before @ character
     else if (i == (iCharAtPosition-1)) {
          bValid = false;
          break;
     // all these are invalid characters
     else if ( c > '~' || c < '!' || c == '(' || c == ')' ||
     c == '<' || c == '>' || c == '[' || c == ']' ||
     c == ',' || c == ';' || c == ':' || c == '\\' ||
     c == '"') {
                         bValid = false;
     break;
          // return the validation flag          
return bValid;
</pre>