跨站请求伪造解决办法之——过滤referer

当然，referer也是可以伪造的，Http请求本身就没有不能伪造的东西。

所以本方法只能在一定程度上防止非法请求，仅供参考。

项目的web.xml中增加过滤器：

    <filter>
        <filter-name>RefererFilter</filter-name>
        <filter-class>com.sdyy.common.filters.RefererFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>RefererFilter</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>  

项目中增加RefererFilter类：

package com.sdyy.common.filters;

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.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;  

public class RefererFilter extends HttpServlet implements Filter {  

    private static final long serialVersionUID = 1L;
    private FilterConfig filterConfig;  

    public void init(FilterConfig config) {
        this.filterConfig = config;
    }  

    public void doFilter(ServletRequest req, ServletResponse res,
            FilterChain chain) throws ServletException, IOException {  

        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
        // 链接来源地址
        String referer = request.getHeader("referer");
        if (referer == null || !referer.contains(request.getServerName())) {
            /**
             * 如果 链接地址来自其他网站，则返回错误页面
             */
            request.getRequestDispatcher("/WEB-INF/error.jsp").forward(request, response);
        } else {
            chain.doFilter(request, response);
        }
    }  

    public void destroy() {
        this.filterConfig = null;
    }  

}