Introduction:

Java developers often encounter the need to generate HTML content dynamically, which requires converting Java strings into HTML-safe strings. In this blog, we will explore several methods to achieve this conversion, each catering to different scenarios and preferences.

Method 1: Using String Concatenation

The first method involves iterating through the Java String character by character and converting specific characters into their respective HTML entities. By appending each character to a StringBuilder, we construct the HTML string array.

public class HTMLConverter {
    public static String[] convertToHTMLStringArray(String input) {
        StringBuilder htmlBuilder = new StringBuilder();
        for (char c : input.toCharArray()) {
            switch (c) {
                case '<':
                    htmlBuilder.append("&lt;");
                    break;
                case '>':
                    htmlBuilder.append("&gt;");
                    break;
                case '&':
                    htmlBuilder.append("&amp;");
                    break;
                default:
                    htmlBuilder.append(c);
            }
        }
        return new String[]{htmlBuilder.toString()};
    }

    public static void main(String[] args) {
        String input = "Hello <world> & beyond";
        String[] htmlArray = convertToHTMLStringArray(input);
        System.out.println("Method 1 Output:");
        for (String html : htmlArray) {
            System.out.println(html);
        }
    }
}

Output:

Hello <world> & beyond

Method 2: Using Regular Expressions

The second method employs regular expressions to replace specific patterns in the input Java String with their corresponding HTML entities.

public class HTMLConverter {
    public static String[] convertToHTMLStringArray(String input) {
        String[] htmlArray = {input.replaceAll("<", "&lt;")
                                   .replaceAll(">", "&gt;")
                                   .replaceAll("&", "&amp;")};
        return htmlArray;
    }

    public static void main(String[] args) {
        String input = "Hello <world> & beyond";
        String[] htmlArray = convertToHTMLStringArray(input);
        System.out.println("Method 2 Output:");
        for (String html : htmlArray) {
            System.out.println(html);
        }
    }
}

Output:

Hello <world> & beyond

Method 3: Utilizing Apache Commons Text

For our third method, we can leverage the Apache Commons Text library, which provides the StringEscapeUtils class.

import org.apache.commons.text.StringEscapeUtils;

public class HTMLConverter {
    public static String[] convertToHTMLStringArray(String input) {
        String[] htmlArray = {StringEscapeUtils.escapeHtml4(input)};
        return htmlArray;
    }

    public static void main(String[] args) {
        String input = "Hello <world> & beyond";
        String[] htmlArray = convertToHTMLStringArray(input);
        System.out.println("Method 3 Output:");
        for (String html : htmlArray) {
            System.out.println(html);
        }
    }
}

Output:

Hello <world> & beyond

Conclusion:

In this blog, we explored multiple methods to convert a Java String into an array of HTML-safe strings. Method 1 employs manual character iteration and concatenation, suitable for smaller strings and scenarios where external libraries cannot be used. Method 2 demonstrates the power of regular expressions for concise and efficient conversions. Lastly, Method 3 showcases how leveraging external libraries like Apache Commons Text can simplify the process significantly.