xss filter by nutz

XssFilter.java

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class XssFilter implements Filter {  
      
    @Override  
    public void init(FilterConfig filterConfig) throws ServletException {  
    }  
  
    @Override  
    public void doFilter(ServletRequest request, ServletResponse response,  
            FilterChain chain) throws IOException, ServletException {  
        chain.doFilter(new XssHttpServletRequestWrapper((HttpServletRequest) request), response);  
    }  
  
    @Override  
    public void destroy() {  
    }  
}

XssHttpServletRequestWrapper.java

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import org.apache.commons.lang3.StringEscapeUtils;

public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {

    public XssHttpServletRequestWrapper(HttpServletRequest request) {
        super(request);
    }

    @Override
    public String getParameter(String name) {
        return StringEscapeUtils.escapeHtml4(super.getParameter(name));
    }

    @Override
    public String[] getParameterValues(String name) {
        String[] values = super.getParameterValues(name);
        if (values != null) {
            int length = values.length;
            String[] escapseValues = new String[length];
            for (int i = 0; i < length; i++) {
                escapseValues[i] = StringEscapeUtils.escapeHtml4(values[i]);
            }
            return escapseValues;
        }
        return values;
    }

}