Java – Calculate Execution Time

import java.util.Date;

public class TimeMillisecond {
  public static void main(String[] argv) {

      long lStartTime = new Date().getTime(); //start time

      String sArray1[] = createArray(); //method execute

      long lEndTime = new Date().getTime(); //end time

      long difference = lEndTime - lStartTime; //check different

      System.out.println("Elapsed milliseconds: " + difference);

  }

  static String [] createArray(){

	  String sArray[] = new String [100000];

	  for(int i=0; i<100000; i++)
		  sArray[i] = "Array " + i;

	  return sArray;
  }
}

Java – Username Validation with Regular Expression

Username Regular Expression Pattern:

^[a-z0-9_-]{3,15}$

Description:

^    # Start of the line
[a-z0-9_-] # Match characters and symbols in the list, a-z, 0-9, underscore, hyphen
{3,15} # Length at least 3 characters and maximum length of 15
$ # End of the line

Example:

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

public class UsernameValidator {

	  private Pattern pattern;
	  private Matcher matcher;

	  private static final String USERNAME_PATTERN = "^[a-z0-9_-]{3,15}$";

	  public UsernameValidator() {
		  pattern = Pattern.compile(USERNAME_PATTERN);
	  }

	  /**
	   * Validate username with regular expression
	   * @param username username for validation
	   * @return true valid username, false invalid username
	   */
	  public boolean validate(final String username) {

		  matcher = pattern.matcher(username);
		  return matcher.matches();

	  }
}

Java – Open Browser in Windows or Linux

A very useful Java code, to open a web browser from Java application in windows or Linux.

public class StartBrowser {

  public static void main(String args[])
  {
	String url = "http://www.google.com";
	String os = System.getProperty("os.name").toLowerCase();
        Runtime rt = Runtime.getRuntime();

	try {

	    if (os.indexOf( "win" ) >= 0) {

	        // this doesn't support showing urls in the form of "page.html#nameLink"
	        rt.exec( "rundll32 url.dll,FileProtocolHandler " + url);

	    } else if (os.indexOf( "mac" ) >= 0) {

	        rt.exec( "open " + url);

            } else if (os.indexOf( "nix") >=0 || os.indexOf( "nux") >=0) {

	        // Do a best guess on unix until we get a platform independent way
	        // Build a list of browsers to try, in this order.
	        String[] browsers = {"epiphany", "firefox", "mozilla", "konqueror",
	       			             "netscape","opera","links","lynx"};

	        // Build a command string which looks like "browser1 "url" || browser2 "url" ||..."
	        StringBuffer cmd = new StringBuffer();
	        for (int i=0; i<browsers.length; i++)
	            cmd.append( (i==0  ? "" : " || " ) + browsers[i] +" \"" + url + "\" ");

	        rt.exec(new String[] { "sh", "-c", cmd.toString() });

           } else {
                return;
           }
       } catch (Exception e) {
	    return;
       }
      return;		

}

Page 30 of 49« First...1020...2829303132...40...Last »