java过滤器处理xss

以下是Java过滤器处理XSS攻击的示例代码：

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.*;

public class XssFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        MyHttpServletRequestWrapper requestWrapper = new MyHttpServletRequestWrapper((HttpServletRequest) servletRequest);
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        filterChain.doFilter(requestWrapper, response);
    }

    @Override
    public void destroy() {
    }

    private class MyHttpServletRequestWrapper extends HttpServletRequestWrapper {

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

        @Override
        public String getParameter(String name) {
            String value = super.getParameter(name);
            if (value != null) {
                value = cleanXSS(value);
            }
            return value;
        }

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

        @Override
        public Enumeration<String> getParameterNames() {
            List<String> names = Collections.list(super.getParameterNames());
            return Collections.enumeration(names);
        }

        @Override
        public Map<String, String[]> getParameterMap() {
            Map<String, String[]> paramMap = super.getParameterMap();
            Map<String, String[]> newParamMap = new HashMap<>();
            for (String key : paramMap.keySet()) {
                String[] values = paramMap.get(key);
                for (int i = 0; i < values.length; i++) {
                    values[i] = cleanXSS(values[i]);
                }
                newParamMap.put(key, values);
            }
            return newParamMap;
        }

        private String cleanXSS(String value) {
            value = value.replaceAll("<", "&lt;").replaceAll(">", "&gt;");
            value = value.replaceAll("\\(", "&#40;").replaceAll("\\)", "&#41;");
            value = value.replaceAll("'", "&#39;");
            value = value.replaceAll("eval\\((.*)\\)", "");
            value = value.replaceAll("[\\\"\\\'][\\s]*javascript:(.*)[\\\"\\\']", "\"\"");
            value = value.replaceAll("script", "");
            return value;
        }
    }
}

该过滤器通过继承HttpServletRequestWrapper类，重写其中的getParameter()、getParameterValues()、getParameterNames()和getParameterMap()方法，对请求参数进行过滤，防止XSS攻击。其中，cleanXSS()方法用于过滤请求参数中的特殊字符和脚本代码。