Escape Character Utility for URL and JSON data – Feel free to use in your Java Project

What is escape character in Java?

Mainly escape characters are the characters which replaces existing character with new & provided character which works best without throwing any error at runtime. Also, it’s required in order for inter systems/process transmission, i.e. same char works for C++, Java, etc programming language.

In this tutorial we will go over two Escape Character Utilities.

1. URLEscapeUtil
2. JSONEscapeUtil

Also this tutorial will help you if you have below questions:

• Java escape characters in string
• Which characters need to be escaped on HTML
• What does escape char means in java
• Java escape characters in string
• How do I escape a String for Java?
• Escape Sequences in Java with Examples

Let’s get started:

1. Create class CrunchifyEscapeCharUtility.java
   
2. Create method crunchifyURLEscapeUtil(String s) – which returns String with escape character in provided URL
3. Create method crunchifyJSONEscapeUtil(String s) – which returns String with escape character in provided JSON
4. In Main() –
   1. we will read the JSON data from file
   2. provide file name is Crunchify_Escape_Util.txt
5. We use java.net.URLEncoder to add URL escape char

In Java when we encode a String, the following rules apply:

Here is a Crunchify_Escape_Util.txt file content. Please put it into your laptop/desktop and update path location in program.

{
    "founder": "App Shah",
    "blogURL": "https://crunchify.com",
    "twitter": "https://twitter.com/Crunchify",
    "social": {
        "facebook": "http://facebook.com/Crunchify",
        "pinterest": "https://www.pinterest.com/Crunchify/crunchify-articles”,
        "rss": "http://feeds.feedburner.com/Crunchify"
    }
}

Here is a complete Java Example

package crunchify.com.tutorial;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.text.StringCharacterIterator;

/**
 * @author Crunchify.com 
 * Version: 1.0 
 * Updated: 01.25.2016
 * 
 */

public class CrunchifyEscapeCharUtility {

	public static void main(String[] args) {

		// URL Escape Utility
		String crunchifyURL = "https://crunchify.com/this is test";
		crunchifyLog("Sample URL: " + crunchifyURL);
		crunchifyLog("Escaped URL: " + crunchifyURLEscapeUtil(crunchifyURL));

		// JSON Escape Utility
		// We will read file first and then we will do escape char on that
		String jsonData = "";
		BufferedReader br = null;
		try {
			String line;
			br = new BufferedReader(
					new FileReader("/Users/<Username>/Documents/Crunchify_Escape_Util.txt"));
			while ((line = br.readLine()) != null) {
				jsonData += line + "\n";
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if (br != null)
					br.close();
			} catch (IOException ex) {
				ex.printStackTrace();
			}
		}

		// Let's print raw JSON file data
		crunchifyLog("\n Sample JSON: " + jsonData.toString());

		// Let's print data after escaping JSON strings
		crunchifyLog("Escaped JSON: " + crunchifyJSONEscapeUtil(jsonData.toString()));

	}

	// Used to ensure that HTTP query strings are in proper form, by escaping special characters such as spaces.
	// Translates a string into application/x-www-form-urlencoded format using a specific encoding scheme
	public static String crunchifyURLEscapeUtil(String crunchifyURL) {
		String crunchifyNewURL = null;
		try {
			crunchifyNewURL = URLEncoder.encode(crunchifyURL, "UTF-8");
		} catch (UnsupportedEncodingException ex) {
			throw new RuntimeException("UTF-8 not supported", ex);
		}
		return crunchifyNewURL;
	}

	// JSON Escape Utility
	public static String crunchifyJSONEscapeUtil(String crunchifyJSON) {
		final StringBuilder crunchifyNewJSON = new StringBuilder();

		// StringCharacterIterator class iterates over the entire String
		StringCharacterIterator iterator = new StringCharacterIterator(crunchifyJSON);
		char myChar = iterator.current();

		// DONE = \\uffff (not a character)
		while (myChar != StringCharacterIterator.DONE) {
			if (myChar == '\"') {
				crunchifyNewJSON.append("\\\"");
			} else if (myChar == '\t') {
				crunchifyNewJSON.append("\\t");
			} else if (myChar == '\f') {
				crunchifyNewJSON.append("\\f");
			} else if (myChar == '\n') {
				crunchifyNewJSON.append("\\n");
			} else if (myChar == '\r') {
				crunchifyNewJSON.append("\\r");
			} else if (myChar == '\\') {
				crunchifyNewJSON.append("\\\\");
			} else if (myChar == '/') {
				crunchifyNewJSON.append("\\/");
			} else if (myChar == '\b') {
				crunchifyNewJSON.append("\\b");
			} else {

				// nothing matched - just as text as it is.
				crunchifyNewJSON.append(myChar);
			}
			myChar = iterator.next();
		}
		return crunchifyNewJSON.toString();
	}

	// Simple log utility
	private static void crunchifyLog(String crunchifyData) {
		System.out.println(crunchifyData);
	}

}

Eclipse Console Output:

Sample URL: https://crunchify.com/this is test
Escaped URL: http%3A%2F%2Fcrunchify.com%2Fthis+is+test

 Sample JSON: {
    "founder": "App Shah",
    "blogURL": "https://crunchify.com",
    "twitter": "https://twitter.com/Crunchify",
    "social": {
        "facebook": "http://facebook.com/Crunchify",
        "pinterest": "https://www.pinterest.com/Crunchify/crunchify-articles”,
        "rss": "http://feeds.feedburner.com/Crunchify"
    }
}

Escaped JSON: {\n    "founder": "App Shah",\n    \"blogURL\": \"http:\/\/crunchify.com\",\n    \"twitter\": \"http:\/\/twitter.com\/Crunchify\",\n    \"social\": {\n        \"facebook\": \"http:\/\/facebook.com\/Crunchify\",\n        \"pinterest\": \"https:\/\/www.pinterest.com\/Crunchify\/crunchify-articles”,\n        \"rss\": \"http:\/\/feeds.feedburner.com\/Crunchify\"\n    }\n}\n

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