JSP 接收 FORM 提交 - Java / Web 开发

一个JSP页面接收其他页面提交过来的FORM表单，但是要求只接收当前站点及其子站点提交过来的FORM表单，其他站点提交过来的表单不接收，这个怎么设置？

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用过滤器
filter
将当前站点及其子站点放一个目录 
然后filter里面的路径配置成该目录

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import java.io.IOException;
import java.io.OutputStream;

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

import org.apache.log4j.Logger;



/**
 * Copyright (c) 2007 

 * @date: Dec 7, 2007
 * @verison 1.0
 * @modify date 
 **/

public class CheckDomainFilter
  extends HttpServlet
  implements Filter {
  public static long count = 0;
  public static long totalMillSec = 0;

  //Handle the passed-in FilterConfig
  public void init(FilterConfig filterConfig) throws ServletException {
   
   
  }

  public void doFilter(ServletRequest request,