Java正则表达式校验某个字符串是否是合格的email

可以借助正则表达式校验某个字符串是否是合规的电子邮箱。对于邮箱的正则表达式有严格的模式，如：^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$
对应的Java实现如下：

package EmailValidationExamples.Regex01;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class EmailValidatorStrict {
  private static final String EMAIL_PATTERN =
  		   "^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$";
  //initialize the Pattern object
  private static final Pattern pattern = Pattern.compile(EMAIL_PATTERN);
  
  // check if the email is valid
  public static boolean isValid(final String email) {
  	Matcher matcher = pattern.matcher(email);
  	return matcher.matches();
  }

}

对应的测试代码如下：

package EmailValidationExamples.Regex01;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class EmailValidation {
   public static void main(String args[]) {
       //adding  emails to an array list
       List<String> emails = new ArrayList<String>();
       //valid email addresses
       emails.add("alice@example.com");
       emails.add("alice.bob@example.com");
       emails.add("alice@example.me.org");
       //invalid email addresses
       emails.add("alice.example.com");
       emails.add("alice..bob@example.com");
       emails.add("alice@.example.me.org");
       //searching for occurrences of regex
       for (String email : emails) {
           System.out.println("Email " + email + " is " +
        		   (EmailValidatorStrict.isValid(email) ? "valid" : "invalid"));
       }
   }
}