accessfilterservlet.java

java语言中servlet的用法实例

package blogServlet;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.*;

public class AccessFilterServlet implements javax.servlet.Filter{

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

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		// TODO Auto-generated method stub
		System.out.println("Enter AccessFilterServlet:");
		request.setCharacterEncoding("GBK");
		response.setCharacterEncoding("GBK");
		
		HttpServletRequest httpRequest = (HttpServletRequest)request;
		HttpServletResponse httpResponse = (HttpServletResponse)response;
		
		javax.servlet.http.HttpSession session =httpRequest.getSession(); 
		String loginState = (String)session.getAttribute("loginOK");
		
		String url = httpRequest.getServletPath();

		UserInfo user=(UserInfo)session.getAttribute("LoginUser");

		if(null!=user||url.endsWith(".html")||url.endsWith("loginServlet")||url.endsWith(".jsp")||url.endsWith("RegisterPageServlet")){
			chain.doFilter(httpRequest, httpResponse);
		}		
		else{
			httpResponse.getWriter().write("---------未登录用户，请先登录或是注册");
			System.out.println("未登录用户");
			httpRequest.getRequestDispatcher("login.html").include(request, response);
			return ;
		}
		
	}
	
	public void init(FilterConfig filterConfig) throws ServletException {
		// TODO Auto-generated method stub
		
	}

}