import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
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;
import javax.servlet.http.HttpServletResponse;
import com.cynthia.common.utils.StringUtils; //可参见 StringUtils 工具类

/**
 * 防止XSS攻击的过滤器
 *
 * @author Wcy
 */
public class XssFilter implements Filter
{
    /**
     * 排除链接
     */
    public List<String> excludes = new ArrayList<>();

    @Override
    public void init(FilterConfig filterConfig) throws ServletException
    {
        String tempExcludes = filterConfig.getInitParameter("excludes");
        if (StringUtils.isNotEmpty(tempExcludes))
        {
            String[] url = tempExcludes.split(",");
            for (int i = 0; url != null && i < url.length; i++)
            {
                excludes.add(url[i]);
            }
        }
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException
    {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse resp = (HttpServletResponse) response;
        if (handleExcludeURL(req, resp))
        {
            chain.doFilter(request, response);
            return;
        }
        XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper((HttpServletRequest) request);
        chain.doFilter(xssRequest, response);
    }

    private boolean handleExcludeURL(HttpServletRequest request, HttpServletResponse response)
    {
        String url = request.getServletPath();
        String method = request.getMethod();
        // GET DELETE 不过滤
        if (method == null || method.matches("GET") || method.matches("DELETE"))
        {
            return true;
        }
        return StringUtils.matches(url, excludes);
    }

    @Override
    public void destroy()
    {

    }
}

XssHttpServletRequestWrapper:

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import com.cynthia.common.utils.html.EscapeUtil;//参见 EscapeUtil 转义和反转义工具类

/**
 * XSS过滤处理
 *
 * @author Wcy
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper
{
    /**
     * @param request
     */
    public XssHttpServletRequestWrapper(HttpServletRequest request)
    {
        super(request);
    }

    @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++)
            {
                // 防xss攻击和过滤前后空格
                escapseValues[i] = EscapeUtil.clean(values[i]).trim();
            }
            return escapseValues;
        }
        return super.getParameterValues(name);
    }
}