一.准备
没什么好说的，直接上代码。。。。
下面是web.xml
<servlet>
<servlet-name>list_user</servlet-name>
<servlet-class>servlet.UserList</servlet-class>
</servlet>
<display-name>servlet_2</display-name>
<servlet-mapping>
<servlet-name>list_user</servlet-name>
<url-pattern>/userList</url-pattern>
</servlet-mapping>
文档结构如下
二.代码实现
package bean;
import java.util.List;
public class PageBean {
private int rowCount;
private int pageSize;
private int pageCount;
private int pageNum;
private List contents;
//下面是get、set方法
}
package bean;
import java.util.Date;
public class User {
private int id;
private String username;
private String password;
private Date birthday;
//下面是get/set
}
package dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DbTool {
public static Connection getConnection(){
Connection conn = null;
try{
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://127.0.0.1/db_user";
String uid = "root";
String pid = "root";
conn = DriverManager.getConnection(url,uid,pid);
}catch(Exception exp){
exp.printStackTrace();
}
return conn;
}
public static void closeConnection(Connection conn){
try {
if(null != conn && !conn.isClosed()){
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public static Object getOneResult(String cmd){
Object o = null;
Connection conn = getConnection();
try {
Statement st = conn.createStatement();
ResultSet rs = st.executeQuery(cmd);
if(rs.next()){
o = rs.getObject(1);
}
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
closeConnection(conn);
return o;
}
public static int execute(String cmd){
Connection conn = getConnection();
int result = 0;
try {
Statement st = conn.createStatement();
result = st.executeUpdate(cmd);
} catch (SQLException e) {
e.printStackTrace();
}
closeConnection(conn);
return result;
}
}
package dao;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import bean.PageBean;
import bean.User;
public class UserDao {
public static void add(User u){
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String cmd = "insert into t_user (username,password,birthday) values('"+
u.getUsername()+"','"+
u.getPassword()+"','"+
sdf.format(u.getBirthday())+"')";
DbTool.execute(cmd);
}
public static void delete(int id){
String cmd = "delete from t_user where id="+id;
DbTool.execute(cmd);
}
public static void update(User u){
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String cmd = "update t_user set username='"+
u.getUsername()+"',password='"+
u.getPassword()+"',birthday='"+
sdf.format(u.getBirthday())+"' where id="+
u.getId();
DbTool.execute(cmd);
}
public static int getUsersCount(){
int count = 0;
String cmd = "select count(*) from t_user";
Object o = DbTool.getOneResult(cmd);
if(null != o){
count = ((Long)o).intValue();
}
return count;
}
public static PageBean getSomeUser(int pageSize,int pageNum){
PageBean pb = new PageBean();
int rowCount = getUsersCount();
int pageCount = rowCount%pageSize ==0 ? rowCount/pageSize: rowCount/pageSize+1;
if(pageNum<1)pageNum = 1;
if(pageNum>pageCount)pageNum=pageCount;
int first = (pageNum-1)*pageSize;
String cmd = "select * from t_user limit "+first+","+pageSize;
Connection conn = DbTool.getConnection();
List<User> users = new ArrayList<User>();
try{
Statement st = conn.createStatement();
ResultSet rs = st.executeQuery(cmd);
while (rs.next()){
User u = new User();
u.setId(rs.getInt(1));
u.setUsername(rs.getString(2));
u.setPassword(rs.getString(3));
u.setBirthday(rs.getDate(4));
users.add(u);
}
}catch(Exception exp){
exp.printStackTrace();
}
DbTool.closeConnection(conn);
pb.setContents(users);
pb.setPageCount(pageCount);
pb.setPageNum(pageNum);
pb.setPageSize(pageSize);
pb.setRowCount(rowCount);
return pb;
}
}
package servlet;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import dao.UserDao;
import bean.PageBean;
public class UserList extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String pn = request.getParameter("pageNum");
int pageNum = 1;
if(null != pn && pn.length()>0){
pageNum = Integer.parseInt(pn);
}
PageBean pb = UserDao.getSomeUser(5, pageNum);
request.setAttribute("pageBean", pb);
RequestDispatcher rd = request.getRequestDispatcher("user_list.jsp");
rd.forward(request, response);
}
}
<%@page import="java.util.Date"%>
<%@page import="java.text.SimpleDateFormat"%>
<%@page import="bean.User"%>
<%@page import="java.util.List"%>
<%@page import="bean.PageBean"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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>
<body>
<table>
<tr>
<td>id</td>
<td>用户名</td>
<td>密码</td>
<td>生日</td>
</tr>
<%
PageBean pb = (PageBean)request.getAttribute("pageBean");
List<User> users = (List<User>)pb.getContents();
int pageNum = pb.getPageNum();
int pageCount = pb.getPageCount();
int pageSize = pb.getPageSize();
int rowCount = pb.getRowCount();
for(User u : users){
Date bir = u.getBirthday();
String birthday = new SimpleDateFormat("yyyy-MM-dd").format(bir);
%>
<tr>
<td><%=u.getId() %></td>
<td><%=u.getUsername() %></td>
<td><%=u.getPassword()%></td>
<td><%=birthday %></td>
</tr>
<%
}
%>
</table>
共<%=rowCount %>条记录，当前是第<%=pageNum %> / <%=pageCount %>页，每页显示<%=pageSize %>条记录。<br/>
<a href="userList?pageNum=1">第一页</a>
<a href="userList?pageNum=<%=pageNum-1 %>">上一页</a>
<a href="userList?pageNum=<%=pageNum+1 %>">下一页</a>
<a href="userList?pageNum=<%=pageCount %>">最后页</a>
</body>
</html>
三.结束语
虽然技术上不是问题，不过怎么分包却是大问题，目前还没有好办法。。。。。