HTMLFilter.java

package util;

public class HTMLFilter {
	    /**
	     * Filter the specified message string for characters that are sensitive
	     * in HTML.  This avoids potential attacks caused by including JavaScript
	     * codes in the request URL that is often reported in error messages.
	     *
	     * @param message The message string to be filtered
	     */
	    public static String filter(String message) {
	    	
	        if (message == null)
	            return (null);

	        char content[] = new char[message.length() + 2];
	        content[0] = '`';
	        content[message.length() + 1] = '`';
	        message.getChars(0, message.length(), content, 1);
	        StringBuilder result = new StringBuilder(content.length + 50);
	        for (int i = 0; i < content.length; i++) {
	            switch (content[i]) {
	            case '<':
	                result.append("<");
	                break;
	            case '>':
	                result.append(">");
	                break;
	            case '&':
	                result.append("&");
	                break;
	            case '"':
	                result.append(""");
	                break;
	            default:
	                result.append(content[i]);
	            }
	        }
	        return (result.toString());

	    }
}