announcefilter.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.BoardDAO;
import edu.liusong.dao.NewsDAO;


public class AnnounceFilter implements Filter {
	public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException,
			ServletException {
		HttpServletRequest request = (HttpServletRequest) arg0;
		if (request.getAttribute("boardList") == null) {
			// 左边导航栏的信息未初始化
			request.setAttribute("boardList", new BoardDAO().getBoards());
		}
		if (request.getAttribute("newsList") == null) {
			// 右侧通知初始化
			request.setAttribute("newsList", new NewsDAO().getTopNews());
		}
		long nid = 0;
		if (request.getParameter("nid") != null) {
			nid = Long.parseLong(request.getParameter("nid"));
		}
		request.setAttribute("news", new NewsDAO().getById(nid));

		arg2.doFilter(arg0, arg1);

	}

	public void destroy() {
	}

	public void init(FilterConfig arg0) throws ServletException {
	}
}