怎么回事，我用JB9写一个简单的过滤SERVELT，没有效果！

我建立WEB应用程序，跟目录下有个login.jsp
跟目录下有个manage目录，在manage目录下有test1.test2两个文件
然后再创建一个filter servlet
代码如：
package dqh.filter;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class SignonFilter extends HttpServlet implements Filter {
private FilterConfig filterConfig;
String LoginPage="login.jsp";
//Handle the passed-in FilterConfig
public void init(FilterConfig filterConfig) {
this.filterConfig = filterConfig;
}
//Process the request/response pair
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) {
HttpServletRequest hreq=(HttpServletRequest)request;
HttpServletResponse hres=(HttpServletResponse)response;
HttpSession session=hreq.getSession();
String isLogin="";
try {
isLogin=(String)session.getAttribute("isLogin");
if(isLogin.equals("true")){
System.out.println("OK");
filterChain.doFilter(request, response);
}
else{
hres.sendRedirect(LoginPage);
System.out.println("Error");
}
}
catch(ServletException sx) {
filterConfig.getServletContext().log(sx.getMessage());
}
catch(IOException iox) {
filterConfig.getServletContext().log(iox.getMessage());
}
}
//Clean up resources
public void destroy() {
this.filterConfig=null;
}
}


然后运行/manage/test1.jsp，它并没有转向login.jsp文件，怎么回事？？？