java防止脚本注入，通过拦截器实现

1:利用action过滤

package com.tsou.comm.servlet;

import java.util.Enumeration;
import java.util.Map;
import java.util.Vector;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
/**
 *
 * <p class="detail">
 * 功能：封装的请求处理特殊字符
 * </p>
 * @ClassName: TsRequest
 * @version V1.0
 * @date 2014年9月25日
 * @author wangsheng
 */
public class TsRequest extends HttpServletRequestWrapper {
           private Map params;

           public TsRequest(HttpServletRequest request, Map newParams) {
                    super(request);
                    this.params = newParams;
          }

           public Map getParameterMap() {
                    return params ;
          }

           public Enumeration getParameterNames() {
                    Vector l = new Vector( params.keySet());
                    return l.elements();
          }

           public String[] getParameterValues(String name) {
                   Object v = params.get(name);
                    if (v == null ) {
                              return null ;
                   } else if (v instanceof String[]) {
                             String[] value = (String[]) v;
                              for (int i = 0; i < value.length; i++) {
                                      value[i] = value[i].replaceAll( "<", "&lt;" );
                                      value[i] = value[i].replaceAll( ">", "&gt;" );
                             }
                              return (String[]) value;
                   } else if (v instanceof String) {
                             String value = (String) v;
                             value = value.replaceAll( "<", "&lt;" );
                             value = value.replaceAll( ">", "&gt;" );
                              return new String[] { (String) value };
                   } else {
                              return new String[] { v.toString() };
                   }
          }

           public String getParameter(String name) {
                   Object v = params.get(name);
                    if (v == null ) {
                              return null ;
                   } else if (v instanceof String[]) {
                             String[] strArr = (String[]) v;
                              if (strArr.length > 0) {
                                      String value = strArr[0];
                                      value = value.replaceAll( "<", "&lt;" );
                                      value = value.replaceAll( "<", "&gt;" );
                                       return value;
                             } else {
                                       return null ;
                             }
                   } else if (v instanceof String) {
                             String value = (String) v;
                             value = value.replaceAll( "<", "&lt;" );
                             value = value.replaceAll( ">", "&gt;" );
                              return (String) value;
                   } else {
                              return v.toString();
                   }
          }
}

2：利用拦截器过滤

package com.kadang.wp.mobile.wap.core.common;

import java.io.IOException;
import java.util.Enumeration;

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 org.apache.commons.lang3.StringUtils;

/**
 * XSS 检查过滤器
 *
 * @author jianghao
 * @date 2014-08-22
 *
 */

public class XSSCheckFilter implements Filter {
    // 需要拦截的JS字符关键字

    private String errorPath;
    // 非法xss 字符
    private static String[] SAFE_LESS = { "set-cookie", "<", "%3c", "%3e", ">", "\\" };

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        this.setErrorPath(filterConfig.getInitParameter("errorPath"));
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException,
            ServletException {
        boolean isSafe = true;

        Enumeration<?> params = req.getParameterNames();
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;
        String requestUrl = request.getRequestURI();

        if (isSafeStr(requestUrl)) {
            while (params.hasMoreElements()) {
                String paramKey = (String) params.nextElement();
                String paramValue = request.getParameter(paramKey);
                if (StringUtils.isNotBlank(paramValue)) {
                    if (!isSafeStr(paramValue)) {
                        isSafe = false;
                        break;
                    }
                }

            }
        } else {
            isSafe = false;
        }

        if (isSafe) {
            chain.doFilter(req, resp);
        } else {
            request.setAttribute("error", "url or params is full of illegal XSS character");
            request.getRequestDispatcher(this.getErrorPath()).forward(request, response);
            return;
        }
    }

    /**
     * 判断URL是否存在非法字符
     * */
    private boolean isSafeStr(String str) {
        if (StringUtils.isNotBlank(str)) {
            for (String s : SAFE_LESS) {
                if (str.toLowerCase().contains(s)) {
                    return false;
                }
            }
        }
        return true;
    }

    @Override
    public void destroy() {

    }

    public String getErrorPath() {
        return errorPath;
    }

    public void setErrorPath(String errorPath) {
        this.errorPath = errorPath;
    }
}

3：利用拦截器拦截URL

<filter>
                    <filter-name> characterFilter</filter-name >
                     <filter-class> com.tsou.comm.filter.CharacterFilter</filter-class >
           </filter>
           <filter-mapping>
                    <filter-name> characterFilter</filter-name >
                    <url-pattern> /*</ url-pattern>
           </filter-mapping>