indexfilter.java

java web网络编程示例,原代码资源

package edu.liusong.filter;

import java.io.IOException;

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

import edu.liusong.dao.ArticleDAO;
import edu.liusong.dao.BoardDAO;
import edu.liusong.dao.HeadLineDAO;
import edu.liusong.dao.NewsDAO;

public class IndexFilter implements Filter {

	protected FilterConfig config = null;

	public void destroy() {
		config = null;
	}

	public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException,
			ServletException {
		HttpServletRequest request=(HttpServletRequest) arg0;
		if(request.getAttribute("boardList")==null){
			//左边导航栏的信息初始化
			request.setAttribute("boardList", new BoardDAO().getBoards());
		}
		if(request.getAttribute("newsList")==null){
			//右侧通知初始化
			request.setAttribute("newsList", new NewsDAO().getTopNews());
		}
		if(request.getAttribute("articleList")==null){
			//中间最新动态初始化
			//String pageSize=config.getInitParameter("pageSize");
			//request.setAttribute("articleList", new ArticleDAO().getTopArticles(pageSize));
		}
		if(request.getAttribute("headline")==null){
			//初始化头条
			request.setAttribute("headline", new HeadLineDAO().getHeadLine());
		}
		arg2.doFilter(arg0, arg1);

	}

	public void init(FilterConfig arg0) throws ServletException {
		this.config = arg0;
	}

}