Java Code - Url Shortener

Java Code - Url Shortener.java

package testjava;

import java.util.HashMap;
import java.util.Random;

/*
 * URL Shortener
 */
public class URLShortener {
	// storage for generated keys
	private HashMap<String, String> keyMap; // key-url map
	private HashMap<String, String> valueMap;// url-key map to quickly check
												// whether an url is
	// already entered in our system
	private String domain; // Use this attribute to generate urls for a custom
							// domain name defaults to http://fkt.in
	private char myChars[]; // This array is used for character to number
							// mapping
	private Random myRand; // Random object used to generate random integers
	private int keyLength; // the key length in URL defaults to 8

	// Default Constructor
	URLShortener() {
		keyMap = new HashMap<String, String>();
		valueMap = new HashMap<String, String>();
		myRand = new Random();
		keyLength = 8;
		myChars = new char[62];
		for (int i = 0; i < 62; i++) {
			int j = 0;
			if (i < 10) {
				j = i + 48;
			} else if (i > 9 && i <= 35) {
				j = i + 55;
			} else {
				j = i + 61;
			}
			myChars[i] = (char) j;
		}
		domain = "http://fkt.in";
	}

	// Constructor which enables you to define tiny URL key length and base URL
	// name
	URLShortener(int length, String newDomain) {
		this();
		this.keyLength = length;
		if (!newDomain.isEmpty()) {
			newDomain = sanitizeURL(newDomain);
			domain = newDomain;
		}
	}

	// shortenURL
	// the public method which can be called to shorten a given URL
	public String shortenURL(String longURL) {
		String shortURL = "";
		if (validateURL(longURL)) {
			longURL = sanitizeURL(longURL);
			if (valueMap.containsKey(longURL)) {
				shortURL = domain + "/" + valueMap.get(longURL);
			} else {
				shortURL = domain + "/" + getKey(longURL);
			}
		}
		// add http part
		return shortURL;
	}

	// expandURL
	// public method which returns back the original URL given the shortened url
	public String expandURL(String shortURL) {
		String longURL = "";
		String key = shortURL.substring(domain.length() + 1);
		longURL = keyMap.get(key);
		return longURL;
	}

	// Validate URL
	// not implemented, but should be implemented to check whether the given URL
	// is valid or not
	boolean validateURL(String url) {
		return true;
	}

	// sanitizeURL
	// This method should take care various issues with a valid url
	// e.g. www.google.com,www.google.com/, http://www.google.com,
	// http://www.google.com/
	// all the above URL should point to same shortened URL
	// There could be several other cases like these.
	String sanitizeURL(String url) {
		if (url.substring(0, 7).equals("http://"))
			url = url.substring(7);

		if (url.substring(0, 8).equals("https://"))
			url = url.substring(8);

		if (url.charAt(url.length() - 1) == '/')
			url = url.substring(0, url.length() - 1);
		return url;
	}

	/*
	 * Get Key method
	 */
	private String getKey(String longURL) {
		String key;
		key = generateKey();
		keyMap.put(key, longURL);
		valueMap.put(longURL, key);
		return key;
	}

	// generateKey
	private String generateKey() {
		String key = "";
		boolean flag = true;
		while (flag) {
			key = "";
			for (int i = 0; i <= keyLength; i++) {
				key += myChars[myRand.nextInt(62)];
			}
			// System.out.println("Iteration: "+ counter + "Key: "+ key);
			if (!keyMap.containsKey(key)) {
				flag = false;
			}
		}
		return key;
	}

	// test the code
	public static void main(String args[]) {
		URLShortener u = new URLShortener(5, "www.tinyurl.com/");
		String urls[] = { "www.google.com/", "www.google.com",
				"http://www.yahoo.com", "www.yahoo.com/", "www.amazon.com",
				"www.amazon.com/page1.php", "www.amazon.com/page2.php",
				"www.flipkart.in", "www.rediff.com", "www.techmeme.com",
				"www.techcrunch.com", "www.lifehacker.com", "www.icicibank.com" };

		for (int i = 0; i < urls.length; i++) {
			System.out.println("URL:" + urls[i] + "\tTiny: "
					+ u.shortenURL(urls[i]) + "\tExpanded: "
					+ u.expandURL(u.shortenURL(urls[i])));
		}
	}
}

I have executed this program and when i hit the shorter url on browser.I got error "Error: Unable to find URL to redirect to."

URL:www.google.com/ Tiny: www.tinyurl.com/H8Y4zT Expanded: www.google.com

please let me know if i missing something

good job!

Excellent, really cool...

Same here, www.google.com gets shortened to www.tinyurl.com/8pwluu but does not work either...

Same here, www.google.com gets shortened to www.tinyurl.com/8pwluu but does not work either...

I have executed this program and when i hit the shorter url on browser.I got error "Error: Unable to find URL to redirect to."

URL:www.google.com/ Tiny: www.tinyurl.com/H8Y4zT Expanded: www.google.com
please let me know if i missing something

Thank you for this.

For people who are seeing "Error: Unable to find URL to redirect to.", the above code is to create your own shortner. It does not use tinyurl or any other external service. If you just want to shorten a url using tinyurl, or bitly, you need to use their APIs. This is not for that purpose.

Redirection is not part of this code. You need something like a nginx setup with rules to perform that.

Thank you so much!

Thank you so much!