java check email format code example

Example: email validator java

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import java.util.Scanner;

public class EmailValidator {

	public static void main(String[] args) {

		recursion();

	}

	static void recursion () {

		Scanner scanner = new Scanner(System.in);

		System.out.println("Welcome to the game of typing a correct email address!");
		
		System.out.println();
		
		System.out.println("As the game says, enter a correct email address.");

		System.out.println();

		String snow = scanner.nextLine();

		String[] sssp = snow.split("@");
		
		if (sssp.length != 2) {
			
		System.out.println();
			
		System.out.println("This is not a correct email address.");	
		
		System.out.println();
			
		recursion();
		
		} else {

			String regex = "[^a-z0-9._]";

			String regex1 = "^\\.|\\.$";
			
			String regex2 = "\s";
			
			String regex3 = "^$";
			
			String regex7 = "\\._|_\\.";
			
			String regex39 = "__";
			
			String regex19 = "\\.\\.";
			
			String regex20 = "^_|_$";

			Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);

			Pattern pattern1 = Pattern.compile(regex1, Pattern.CASE_INSENSITIVE);
			
			Pattern pattern2 = Pattern.compile(regex2, Pattern.CASE_INSENSITIVE);
			
			Pattern pattern3 = Pattern.compile(regex3, Pattern.CASE_INSENSITIVE);
			
			Pattern pattern11 = Pattern.compile(regex7, Pattern.CASE_INSENSITIVE);
			
			Pattern pattern12 = Pattern.compile(regex19, Pattern.CASE_INSENSITIVE);
			
			Pattern pattern13 = Pattern.compile(regex20, Pattern.CASE_INSENSITIVE);
			
			Pattern pattern14 = Pattern.compile(regex39, Pattern.CASE_INSENSITIVE);

			Matcher matcher = pattern.matcher(sssp[0]);

			Matcher matcher1 = pattern1.matcher(sssp[0]);
			
			Matcher matcher2 = pattern2.matcher(sssp[0]);
			
			Matcher matcher3 = pattern3.matcher(sssp[0]);
			
			Matcher matcher11 = pattern11.matcher(sssp[0]);
			
			Matcher matcher12 = pattern12.matcher(sssp[0]);
			
			Matcher matcher13 = pattern13.matcher(sssp[0]);
			
			Matcher matcher14 = pattern14.matcher(sssp[0]);

			boolean matchFound = matcher.find();

			boolean matchFound1 = matcher1.find();
			
			boolean matchFound2 = matcher2.find();
			
			boolean matchFound3 = matcher3.find();
			
			boolean matchFound10 = matcher11.find();
			
			boolean matchFound11 = matcher12.find();
			
			boolean matchFound12 = matcher13.find();
			
			boolean matchFound13 = matcher14.find();
			
			String hello = sssp[1];
			
			String[] whoop = hello.split("\\.", 2);
			
			if (whoop.length != 2) {
				
			System.out.println();

			System.out.println("This is not a correct email address.");	

			System.out.println();	
				
			recursion();
			
			} else {
				
				String regex4 = "[^a-z]";
				
				String regex5 = "^$";
				
				String regex6 = "\s";
				
				Pattern pattern4 = Pattern.compile(regex4, Pattern.CASE_INSENSITIVE);

				Pattern pattern5 = Pattern.compile(regex5, Pattern.CASE_INSENSITIVE);
				
				Pattern pattern6 = Pattern.compile(regex6, Pattern.CASE_INSENSITIVE);
				
				Matcher matcher4 = pattern4.matcher(whoop[0]);

				Matcher matcher5 = pattern5.matcher(whoop[0]);
				
				Matcher matcher6 = pattern6.matcher(whoop[0]);
				
				boolean matchFound4 = matcher4.find();

				boolean matchFound5 = matcher5.find();
				
				boolean matchFound6 = matcher6.find();
				
				Pattern pattern7 = Pattern.compile(regex4, Pattern.CASE_INSENSITIVE);

				Pattern pattern8 = Pattern.compile(regex5, Pattern.CASE_INSENSITIVE);
				
				Pattern pattern9 = Pattern.compile(regex6, Pattern.CASE_INSENSITIVE);
				
				Matcher matcher7 = pattern7.matcher(whoop[1]);

				Matcher matcher8 = pattern8.matcher(whoop[1]);
				
				Matcher matcher9 = pattern9.matcher(whoop[1]);
				
				boolean matchFound7 = matcher7.find();

				boolean matchFound8 = matcher8.find();
				
				boolean matchFound9 = matcher9.find();
				
				System.out.println();

				if(matchFound || matchFound1 || matchFound2 || matchFound3 || matchFound4 || matchFound5 || matchFound6 || matchFound7 || matchFound8 || matchFound9 || matchFound10 || matchFound11 || matchFound12 || matchFound13) {

					System.out.println("This is not a correct email address.");

					System.out.println();

					recursion();

				} else {

					System.out.println("This is a correct email address.");

					System.out.println();

					System.out.println("Do you still want to play? (say yes to play) ");

					System.out.println();

					Scanner scanner1 = new Scanner(System.in);

					String snow1 = scanner1.nextLine();

					if (snow1.equalsIgnoreCase("yes")) {

						System.out.println();

						recursion();

					} else {

						System.out.println();  

						System.out.println("Okay, then.");  
						
						scanner.close();
						
						scanner1.close();
						
					}

				}	
				
			}
			
		}

	}
	
}