studentloginfilter.java

这是我自己做的一个选课系统

package org.chooseClass.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/****************************************************
 * Title: AdminSecurityFilter.java                 
 * @author liuhan                  
 *  Copyright (c) 2007-10-20          
 * 项目 suto
 * 包名　com.suto.servlet                         
 ************************************************/
public class StudentLoginFilter implements Filter {

	public void destroy() {
		// TODO Auto-generated method stub

	}

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
	 */
	public void doFilter(ServletRequest req, ServletResponse res,
			FilterChain chain) throws IOException, ServletException {
		// TODO Auto-generated method stub
		HttpServletRequest request = (HttpServletRequest)req;
		HttpServletResponse response = (HttpServletResponse)res;
		String username = (String) request.getSession().getAttribute("username");
		String type = (String) request.getSession().getAttribute("type");
		
	    if(username==null||username==""||!type.equalsIgnoreCase("student")){
	    	
	    	//response.sendRedirect(request.getContextPath()+"/test");
	    	RequestDispatcher rd = request.getRequestDispatcher("/login.jsp?errmsg=请登录");
			rd.forward(request, response);
	    	return;
	    }
	   
		chain.doFilter(request, response);
	}

	public void init(FilterConfig arg0) throws ServletException {
		// TODO Auto-generated method stub

	}

}