验证email address.

public class EmailAddress
  implements Serializable
{
  String emailAddress;
  FormattedDate lastUpdate;
  private Boolean invalidIndicator;
 
  public EmailAddress(String newEmailAddress, FormattedDate newLastUpdate)
  {
    this.emailAddress = newEmailAddress;
    this.lastUpdate = newLastUpdate;
  }
 
  public EmailAddress(String newEmailAddress, Date newLastUpdate)
  {
    this(newEmailAddress, new FormattedDate(newLastUpdate));
  }
 
  public EmailAddress(String newEmailAddress)
  {
    this.emailAddress = newEmailAddress;
  }
 
  public String getEmailAddress()
  {
    return this.emailAddress;
  }
 
  public FormattedDate getLastUpdate()
  {
    return this.lastUpdate;
  }
 
  public String getLastUpdateFormatted()
  {
    return this.lastUpdate.getDateFormatted();
  }
 
  public Boolean getInvalidIndicator() {
    return this.invalidIndicator;
  }
 
  public void setInvalidIndicator(Boolean invalidIndicator) {
    this.invalidIndicator = invalidIndicator;
  }
 
  public static boolean validate(String email)
  {
    if (email != null) {
      StringBuffer sb = new StringBuffer(email.trim());
      if (sb.length() > 0) {
        int idx = email.indexOf('@');
        if (idx < 0) {
          return false;
        }
      }
    }
    return true;
  }
 
  public static boolean validate2(String email)
  {
    boolean flag = true;
    if (email != null) {
      int idx = email.indexOf("@");
      if ((idx == -1) || (email.indexOf("@", idx + 1) != -1))
        flag = false;
      else if (email.indexOf(".") == -1)
        flag = false;
      else if (email.indexOf(",") != -1)
        flag = false;
      else if (email.indexOf(";") != -1)
        flag = false;
      else if (email.length() < 5)
        flag = false;
      else if (email.indexOf(" ") != -1) {
        flag = false;
      }
      else if (!validCharAfterAtSign(email))
        flag = false;
      else if (!validLastChar(email))
        flag = false;
      else if (idx == 0)
        flag = false;
    }
    else
    {
      flag = false;
    }
    return flag;
  }
 
  public String toString()
  {
    return new StringBuilder().append("EmailAddress: emailAddress=(").append(this.emailAddress == null ? "null" : this.emailAddress).append(") ").append("lastUpdate=(").append(this.lastUpdate == null ? "null" : getLastUpdateFormatted()).append(") ").append("invalidIndicator=(").append(this.invalidIndicator).append(")").toString();
  }
 
  private static boolean validCharAfterAtSign(String str)
  {
    int idx = str.indexOf("@");
    for (int i = idx + 1; i < str.length(); i++) {
      int charInt = str.charAt(i);
 
      if ((charInt != 45) && (charInt != 46) && ((charInt < 48) || (charInt > 57)) && ((charInt < 65) || (charInt > 90)) && ((charInt < 97) || (charInt > 122)))
      {
        return false;
      }
    }
    return true;
  }
 
  private static boolean validLastChar(String str) {
    int charInt = str.charAt(str.length() - 1);
 
    return ((charInt >= 48) && (charInt <= 57)) || ((charInt >= 65) && (charInt <= 90)) || ((charInt >= 97) && (charInt <= 122));
  }
}