This example shows how to use the String.matches() method for testing the regular expressions against any other strings. Using the regular expressions are very efficient to save lot of code for the validations. For example, you can use the pre-defined regular expression to validate the email address without extra code.
package javabeat.net.util; /** * String.matches() example * @author krishna * */ public class StringMatchExample { public static void main(String[] args) { String str = "Java String Examples"; String email = "[email protected]"; // Checks if string has only letters a-z, A-Z System.out.println(str.matches("[a-zA-Z *]+$")); // Checks if string has preceding and trailing word "String" System.out.println(str.matches("(.*)String(.*)")); // Checks if the exact word is Java System.out.println(str.matches("Java")); // Checks if the string starts with letters "Java" System.out.println(str.matches("Java(.*)")); // Checks if string is valid email address System.out.println(email .matches("^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@" + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*" + "(\\.[A-Za-z]{2,})$")); } }
Output
true true false true true