网页分页技术 案例分析
1.主页
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!-- 导入jstl文件 --> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <!-- 获取上下文环境 --> <% String path = request.getContextPath(); %> <!-- 导入jquery包 --> <script src="../js/jquery-1.6.1.min.js"></script> <!-- 绑定事件 --> <script> $(function(){ $(":button").bind("click",function(){ location.href="<%=path%>/Myser"; }); }); </script> <body> <div style="margin-left:400px;"> <!-- 绑定单击事件 --> <input type="button" value="查询"/><br/> <table border="1"> <tr> <th>序号</th> <th>用户名</th> <th>密码</th> <th>性别</th> <th>生日</th> </tr> <!-- 用jstl表达式 循环遍历对象属性 --> <c:forEach items="${list }" var="s" varStatus="i"> <tr> <td>${i.count }</td> <td>${s.getUserName() }</td> <td>${s.getPassword() }</td> <td>${s.getSex() }</td> <td>${s.getDate() }</td> </tr> </c:forEach> <!-- 底栏分页处理 --> <tr> <td colspan="5" align="right"> 第${page.currentPage}页/共${page.totalPage }页 <c:if test="${page.currentPage>1}"> <a href="<%=path %>/Myser?currentP=${page.currentPage-1}">上一页</a> </c:if> <c:if test="${page.currentPage < page.totalPage }"> <a href="<%=path %>/Myser?currentP=${page.currentPage+1}">下一页</a> </c:if> </td> </tr> </table> </div> </body> </html>
2，数据库连接--增删改与查询
package com.mian; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class JDBCUtil { //锟斤拷锟捷匡拷 private static String driver="com.mysql.jdbc.Driver"; private static String url="jdbc:mysql://localhost:3306/zhuece"; private static String user="root"; private static String password="123456"; static Connection conn; static ResultSet set; static PreparedStatement ps; //锟斤拷锟斤拷锟斤拷锟斤拷 static { try { Class.forName(driver); } catch (ClassNotFoundException e) { e.printStackTrace(); } } //锟斤拷锟斤拷锟斤拷 public static void openC() { try { conn=DriverManager.getConnection(url, user, password); } catch (SQLException e) { e.printStackTrace(); } } //锟斤拷删锟侥的凤拷锟斤拷 public static void up(String sql) { openC(); try { ps=conn.prepareStatement(sql); ps.executeUpdate(); } catch (SQLException e) { close(); e.printStackTrace(); } } //锟斤拷询锟侥凤拷锟斤拷 public static ResultSet cha(String sql,Object...args) { openC(); try { ps=conn.prepareStatement(sql); if(args!=null) { int len=args.length; for(int i=0;i<len;i++) { ps.setObject(i+1,args[i]); } } set=ps.executeQuery(); } catch (SQLException e) { e.printStackTrace(); close(); return null; } return set; } public static void close() { if(set!=null) { try { set.close(); } catch (SQLException e) { e.printStackTrace(); }finally { if(ps!=null) { try { ps.close(); } catch (SQLException e) { e.printStackTrace(); }finally { if(conn!=null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } } } } } }
3.数据库中存的对象
package com.mian; public class User { //属性私有化 private String userName; private String password; private String sex; private String date; private int id; //空参构造器 public User() { } //有参（所有属性）构造器 public User(String userName, String password, String sex, String date ,int id) { super(); this.userName = userName; this.password = password; this.sex = sex; this.date = date; this.id=id; } //提供公开的set和get方法 public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public String getDate() { return date; } public void setDate(String date) { this.date = date; } public int getId() { return id; } public void setId(int id) { this.id = id; } }
4.业务逻辑层，封装的增删改与查询的方法
package com.mian; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import Page.Page; public class LianJie { public static List<User> find(Page page) { int current =page.getCurrentPage(); int pageSize=page.getPageSize(); String sql="select *from zhuce limit "+(current-1)*pageSize+","+pageSize; ResultSet set=JDBCUtil.cha(sql); List<User> list = new ArrayList<User>(); try { while(set.next()) { String userNmae=set.getString("username"); String password =set.getString("mima"); String sex=set.getString("sex"); String birth = set .getString("birthday"); int id=set.getInt("id"); User user = new User(userNmae,password,sex,birth,id); list.add(user); } } catch (SQLException e) { e.printStackTrace(); JDBCUtil.close(); } JDBCUtil.close(); return list; } public static int getTotal() { int count =0; String sql="select COUNT(1) from zhuce"; ResultSet set=JDBCUtil.cha(sql); try { while(set.next()) { count=set.getInt("COUNT(1)"); } } catch (SQLException e) { e.printStackTrace(); JDBCUtil.close(); } JDBCUtil.close(); return count; } }
5.分页类，仅用于存储页数的数据
package Page; public class Page { //当前页 private int currentPage; //总页数 private int totalPage; //总记录数 private int totalSize; //每页显示的记录数 private int pageSize; public int getCurrentPage() { return currentPage; } public void setCurrentPage(int currentPage) { this.currentPage = currentPage; } public int getTotalPage() { totalPage = (int)Math.ceil(totalSize/(double)pageSize); return totalPage; } public void setTotalPage(int totalPage) { this.totalPage = totalPage; } public int getTotalSize() { return totalSize; } public void setTotalSize(int totalSize) { this.totalSize = totalSize; } public int getPageSize() { return pageSize; } public void setPageSize(int pageSize) { this.pageSize = pageSize; } }
6.处理html的服务器
package myser; import java.io.IOException; import java.util.List; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.commons.lang3.StringUtils; import com.mian.LianJie; import com.mian.User; import Page.Page; /** * Servlet implementation class Myser */ @WebServlet("/Myser") public class Myser extends HttpServlet { private static final long serialVersionUID = 1L; int currentPage=1; /** * @see HttpServlet#HttpServlet() */ public Myser() { } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { int pageSize=10; Page page = new Page(); int total=LianJie.getTotal(); page.setTotalSize(total); page.setPageSize(pageSize); String currentP=request.getParameter("currentP"); if(StringUtils.isNotBlank(currentP)) { currentPage=Integer.valueOf(currentP); } page.setCurrentPage(currentPage); List<User> list=LianJie.find(page); HttpSession session = request.getSession(); session.setAttribute("page", page); session.setAttribute("list", list); request.getRequestDispatcher("/fenye/mian.jsp").forward(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } }
