创建表
create table t_user(
username varchar(20),
password varchar(20));
insert into t_user values(‘aa‘,‘aa‘);
导入jdbc驱动
e:\oracle\product\10.1.0\Db_3\jdbc\lib\ojdbc14.jar
创建DB类,内容如下:
package util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DB {
private DB() {
}
static {
try {
Class.forName("oracle.jdbc.OracleDriver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public static Connection getConnection() {
Connection con = null;
try {
con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","wt", "wt");
} catch (SQLException e) {
e.printStackTrace();
}
return con;
}
public static void closeConnection(Connection con) {
if (con != null) {
try {
con.close();
con = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static Statement getStatement(Connection con){
Statement statement=null;
try {
statement=con.createStatement();
} catch (SQLException e) {
e.printStackTrace();
}
return statement;
}
public static void closeStatement(Statement statement) {
if (statement != null) {
try {
statement.close();
statement = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static PreparedStatement getPreparedStatement(Connection con,String sql){
PreparedStatement preparedStatement=null;
try {
preparedStatement=con.prepareStatement(sql);
} catch (SQLException e) {
e.printStackTrace();
}
return preparedStatement;
}
/*
* isGeneratedKey:是否获得记录的主键
* Statement.RETURN_GENERATED_KEYS:是否获得记录的主键
* */
public static PreparedStatement getPreparedStatement(Connection con,String sql,boolean isGeneratedKey){
PreparedStatement preparedStatement=null;
try {
if(isGeneratedKey==true){
String generatedColumns[] = {"id"}; //该表的主键
preparedStatement=con.prepareStatement(sql,generatedColumns);
}
} catch (SQLException e) {
e.printStackTrace();
}
return preparedStatement;
}
public static void closePreparedStatement(PreparedStatement preparedStatement) {
if (preparedStatement != null) {
try {
preparedStatement.close();
preparedStatement = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static ResultSet executeQuery(Statement statement,String sql){
ResultSet resultSet=null;
try {
resultSet=statement.executeQuery(sql);
} catch (SQLException e) {
e.printStackTrace();
}
return resultSet;
}
public static void executeUpdate(String sql){
Connection con=DB.getConnection();
PreparedStatement ps=DB.getPreparedStatement(con, sql);
try {
ps.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
}finally{
DB.closePreparedStatement(ps);
DB.closeConnection(con);
}
}
public static void closeResultSet(ResultSet resultSet){
if(resultSet!=null){
try {
resultSet.close();
resultSet=null;
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
创建UserOracleDAO,内容如下:
package dao;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import model.User;
import util.DB;
public class UserOracleDAO {
public List<User> getPage(int pageNumber, int pageSize) {
Connection con = DB.getConnection();
String sql = "";
if (pageNumber == 0) { //如果第一页的话
pageNumber = 1;
sql += "select * from(select a.*, rownum r from( select * from t_user) a where rownum <="
+ pageSize + ") B where r >=" + pageNumber + "";
} else {
pageNumber += 1;
sql += "select * from(select a.*, rownum r from( select * from t_user) a where rownum <="
+ pageNumber
* pageSize
+ ") B where r >"
+ ((pageNumber * pageSize) - pageSize) + "";
}
Statement st = null;
ResultSet rs = null;
List<User> users = new ArrayList<User>();
try {
st = con.createStatement();
rs = st.executeQuery(sql);
while (rs.next()) {
User user = new User();
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
users.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DB.closeResultSet(rs);
DB.closeStatement(st);
DB.closeConnection(con);
}
return users;
}
public int getCounts() {
Connection con = DB.getConnection();
Statement st = DB.getStatement(con);
String sql = "select count(*) from t_user";
ResultSet rs = null;
int count = 0;
try {
rs = st.executeQuery(sql);
if (rs.next()) {
count = rs.getInt("count(*)");
}
} catch (SQLException e) {
e.printStackTrace();
}
return count;
}
//获得首页
public List<User> getFirstPage(int pageSize) {
Connection con = DB.getConnection();
int start=1;
String sql = "select * from(select a.*, rownum r from( select * from t_user) a where rownum <="
+ pageSize + ") B where r >=" +start+ "";
Statement st = null;
ResultSet rs = null;
List<User> users = new ArrayList<User>();
try {
st = con.createStatement();
rs = st.executeQuery(sql);
while (rs.next()) {
User user = new User();
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
users.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DB.closeResultSet(rs);
DB.closeStatement(st);
DB.closeConnection(con);
}
return users;
}
//获得首页
public List<User> getLastPage(int pageCount,int pageSize) {
Connection con = DB.getConnection();
int start=((pageCount*pageSize)-pageSize)+1;
int end=(pageCount*pageSize)+1;
String sql = "select * from(select a.*, rownum r from( select * from t_user) a where rownum <="
+ end + ") B where r >=" +start+ "";
Statement st = null;
ResultSet rs = null;
List<User> users = new ArrayList<User>();
try {
st = con.createStatement();
rs = st.executeQuery(sql);
while (rs.next()) {
User user = new User();
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
users.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DB.closeResultSet(rs);
DB.closeStatement(st);
DB.closeConnection(con);
}
return users;
}
}
创建User内容如下:
package model;
import java.io.Serializable;
public class User implements Serializable{
private String username;
private String password;
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;
}
}
创建UserServlet,内容如下:
package servlet;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import model.User;
import dao.UserOracleDAO;
public class UserServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String method=request.getParameter("method");
UserOracleDAO uod=new UserOracleDAO();
HttpSession session=request.getSession();
int pageSize=5;
int userSize=uod.getCounts(); //获得所有记录
int pageCount=userSize/pageSize==0?userSize/pageSize:userSize/pageSize+1; //判断是否整除,页数是否是整数
if(method.equals("first")){
int currentPage=Integer.parseInt(request.getParameter("currentPage"));
List<User> users=uod.getFirstPage(pageSize);
session.setAttribute("list",users);
session.setAttribute("currentPage",String.valueOf(currentPage));
session.setAttribute("pageCount",String.valueOf(pageCount));
getServletConfig().getServletContext().getRequestDispatcher("/list.jsp").forward(request,response);
return;
}
if(method.equals("last")){
int currentPage=pageCount;
List<User> users=uod.getLastPage(pageCount, pageSize);
session.setAttribute("list",users);
session.setAttribute("currentPage",String.valueOf(currentPage));
session.setAttribute("pageCount",String.valueOf(pageCount));
getServletConfig().getServletContext().getRequestDispatcher("/list.jsp").forward(request,response);
return;
}
if(method.equals("back")){
int currentPage=Integer.parseInt(request.getParameter("currentPage"));
if(currentPage!=0){
currentPage--;
List<User> users=uod.getPage(currentPage,pageSize);
session.setAttribute("list",users);
session.setAttribute("currentPage",String.valueOf(currentPage));
session.setAttribute("pageCount",String.valueOf(pageCount));
getServletConfig().getServletContext().getRequestDispatcher("/list.jsp").forward(request,response);
}
return;
}
if(method.equals("next")){
int currentPage=Integer.parseInt(request.getParameter("currentPage"));
currentPage++;
List<User> users=uod.getPage(currentPage,pageSize);
session.setAttribute("list",users);
session.setAttribute("currentPage",String.valueOf(currentPage));
session.setAttribute("pageCount",String.valueOf(pageCount));
getServletConfig().getServletContext().getRequestDispatcher("/list.jsp").forward(request,response);
return;
}
}
}
配置web.xml,内容如下:
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>UserServlet</servlet-name>
<servlet-class>servlet.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UserServlet</servlet-name>
<url-pattern>/UserServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
创建list.jsp,内容如下:
<%@ page language="java"
import="java.util.*,model.User,dao.UserOracleDAO"
pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<%
List<User> users = (List<User>) session.getAttribute("list");
int currentPage=0; //当前页
int PageCount=0; //总页数
int pageSize=5; //每页显示数据数
if (users != null) {
currentPage=Integer.parseInt((String)session.getAttribute("currentPage"));
PageCount=Integer.parseInt((String)session.getAttribute("pageCount"));
} else {
currentPage=0;
UserOracleDAO uod = new UserOracleDAO();
users = uod.getFirstPage(pageSize);
int userSize=uod.getCounts();
PageCount=userSize/pageSize==0?userSize/pageSize:userSize/pageSize+1; //判断是否整除,页数是否是整数
}
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP ‘index.jsp‘ starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<table border=‘1‘>
<tr>
<td>
用户名
</td>
<td>
密码
</td>
</tr>
<%
for (Iterator<User> it = users.iterator(); it.hasNext();) {
User user = it.next();
%>
<tr>
<td><%=user.getUsername()%></td>
<td><%=user.getPassword()%></td>
</tr>
<%
}
%>
<tr>
<td>
<a href="UserServlet?method=first¤tPage=0">首页</a>
<a href="UserServlet?method=back¤tPage=<%=currentPage%>">上一页</a>
<%if(currentPage==0){ %>
<a>1/<%=PageCount%></a>
<%}else if(currentPage==PageCount){%>
<a><%=PageCount%>/<%=PageCount%></a>
<%}else{ %>
<a><%=currentPage+1%>/<%=PageCount%></a>
<%}%>
<a href="UserServlet?method=next¤tPage=<%=currentPage%>">下一页</a>
<a href="UserServlet?method=last">尾页</a>
</td>
</tr>
</table>
</body>
</html>
Oracle数据库JSP分页
时间： 2024-10-11 22:36:31