regex match number in java

java match number using Matcher

/**
 * @author lautturi.com 
 * Java example: check if a string can be parsed to a number in java
 */

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

public class Lautturi {
	
	public static void main(String[] args)   {

		String str1 = "123456";
		String regex = "[0-9]+"; // "\\d+"
		Pattern pattern = Pattern.compile(regex);
		Matcher matcher = pattern.matcher(str1);
		Boolean b = matcher.matches();  
		System.out.println(b);
		
		String str2 = "123abc";
		Matcher matcher2 = pattern.matcher(str2);
		System.out.println(matcher2.matches());

	}
}

java match number using String.matches()

/**
 * @author lautturi.com 
 * Java example: Tells whether or not the string is a number in java
 */

import java.util.*;

public class Lautturi {
	
	public static void main(String[] args)   {

		String str1 = "123456";
		String regex = "[0-9]+"; // "\\d+"

		Boolean b = str1.matches(regex);
		System.out.println(b);
		
		String str2 = "123abc";
		System.out.println(str2.matches(regex));

	}
}

output:

true
false