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java regex pattern validate html tag

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.


This regular expression refers to a pattern which start with an opening tag “<" , follow by double quotes "string", or single quotes 'string' but does not allow one double quotes (") "string, one single quote (') 'string or a closing tag > without single or double quotes enclosed. At last, end with a closing tag “>”


package com.tutorialspointexamples;
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 = 
	public static void main(String args[]){ 
		List<String> values = new ArrayList<String>();	
		values.add("<input value=> >");
		Pattern pattern = Pattern.compile(PATTERN);
		for (String value : values){
		  Matcher matcher = pattern.matcher(value);
			  System.out.println("Tag "+ value +" is valid");
			  System.out.println("Tag "+ value +" is invalid");


Tag <br> is valid
Tag <input/> is valid
Tag <input value=> > is invalid
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