logonfilter.java

JavaWeb高级特性书中源代码

package org.it315.filters;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpSession;

public class LogonFilter implements Filter
{
	private FilterConfig filterConfig = null;
	
	public void init(FilterConfig filterConfig) throws ServletException
	{
	}
	
	public void doFilter(ServletRequest request,
		ServletResponse response,FilterChain chain)
			throws IOException, ServletException
	{
		HttpServletRequest req = (HttpServletRequest)request;
		HttpSession session = req.getSession();
		
		//如果用户没有登录，存储当前访问的页面路径后跳转到登录页面
		if(session.getAttribute("logonUser") == null)
		{
			String requestURI = req.getRequestURI();
			String contextPath = req.getContextPath();
			String forwardURI = requestURI.substring(contextPath.length());
			session.setAttribute("viewPage",forwardURI);
			RequestDispatcher rd = req.getRequestDispatcher("/logon.jsp");
			rd.forward(req,response);
		}
		else
		{
			chain.doFilter(request, response);
		}
	}

	public void destroy()
	{
	}
}