userlistservlet.java

精通Jsp-Web开发技术与典型应用 源码

package ch18.Servlet;

import java.io.IOException;
import java.util.Collection;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import ch18.JavaBean.DB_User;

/**
 * 
 * @author qq
 * 
 * 用户列表分页显示UserListServlet类
 */

public class UserListServlet extends javax.servlet.http.HttpServlet implements
		javax.servlet.Servlet {

	public UserListServlet() {
		super();
	}

	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {

		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);

		int pagesize = 5;
		String page = request.getParameter("page");
		DB_User dbuser = new DB_User();
		int count = dbuser.getCount(); // 记录总数
		int totalPageNum = count / pagesize; // 计算总页数
		
		// 如果纪录总数除以每页的显示个数,余数大于0,那么
		// 总页数应该为商+1
		if ((count % pagesize) > 0) {
			totalPageNum += 1;
		}
		if (page == null) {
			page = "1";
		}
		
		request.setAttribute("totalPageNum", new Integer(totalPageNum));
		Collection c = dbuser.getAll(pagesize, Integer.parseInt(page));
		request.setAttribute("c", c);
		try {
			request.getRequestDispatcher("userlist.jsp").forward(request,
					response);
		} 
		catch (Throwable t) {
			getServletContext().log(t.getMessage());
		}
	}
}