CodesJava

Easy learning with example program codes

java regex pattern validate email


Regular expressions

Regular expressions represents a sequence of symbols and characters expressing a string or pattern to be searched for within a longer piece of text. The abbreviation for regular expression is regex. In programming regular expressions are mainly used to define constraint on strings like password, email validation.

Regular expression email pattern

^[_A-Za-z0-9-\+]+(\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\.[A-Za-z0-9]+)*(\.[A-Za-z]{2,})$

This regular expression refers to a pattern which must start with “_A-Za-z0-9-\+” , optional follow by “.[_A-Za-z0-9-]”, and end with a “@” symbol. The email’s domain name must start with “A-Za-z0-9-“, follow by first level Tld (.com, .net) “.[A-Za-z0-9]” and optional follow by a second level Tld (.com.au, .com.my) “\.[A-Za-z]{2,}”, where second level Tld must start with a dot “.” and length must equal or more than 2 characters.

Example

package com.codesjava;
 
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class RegexTest {
	private static final String PATTERN = 
			"^[_A-Za-z0-9-\+]+(\.[_A-Za-z0-9-]+)*@"
			+ "[A-Za-z0-9-]+(\.[A-Za-z0-9]+)*(\.[A-Za-z]{2,})$";
	public static void main(String args[]){ 
		List<String> values = new ArrayList<String>();	
		values.add("jaisingh70@yahoo.com"); 
		values.add("jaipannu99@gmail.com"); 
		values.add("jaipannu99@.com");
		values.add("jaipannu99@gmail.com.a");
 
		Pattern pattern = Pattern.compile(PATTERN);
		for (String value : values){
		  Matcher matcher = pattern.matcher(value);
		  if(matcher.matches()){
			  System.out.println("Email "+ value +" is valid");
		  }else{
			  System.out.println("Email "+ value +" is invalid");
		  }		  
		}
	}
}

Output

Email jaisingh70@yahoo.com is valid
Email jaipannu99@gmail.com is valid
Email jaipannu99@.com is invalid
Email jaipannu99@gmail.com.a is invalid


Copyright © 2018 CodesJava DMCA.com Protection Status SiteMap