isavailable.java

java web开发宝典源代码

package com.yxq.filter;

import java.io.IOException;
import java.util.Date;

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;
import javax.servlet.http.HttpSession;

public class isAvailable implements Filter {
	private FilterConfig filterconfig=null;

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

	public void doFilter(ServletRequest Srequest,ServletResponse Sresponse,FilterChain chain) throws IOException, ServletException {
		HttpServletResponse response=(HttpServletResponse)Sresponse;
		HttpServletRequest request=(HttpServletRequest)Srequest;
		HttpSession session=request.getSession();
		if(session.getAttribute("available")==null){
			RequestDispatcher rd=request.getRequestDispatcher("/message.jsp");
			rd.forward(request,response);
		}
		else{
			chain.doFilter(Srequest,Sresponse);	
		}		
	}

	public void init(FilterConfig filterconfig) throws ServletException {
		this.filterconfig=filterconfig;
	}
}