不說廢話，首先，建立要連接的數據庫，我的數據庫名稱是collage，要顯示的數據表是students，有六列，要學習並測試的可以自己建立數據庫。
id:int
name:varchar
grade:int
batch:int
password:int
gxqm:varchar
JSP頁面，有三個，login.jsp,loginhandle.jsp,welcome.jsp。java類有三個，Userbean用於映射數據對象，UserbeanCl用於業務邏輯處理，connDB用於建立數據庫連接。直接上代碼吧
login.jsp頁面
<%@ 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>Login in and then enjoy yourself!</title>
</head>
<body>
<center>
請登錄
<form name="form1" action="loginhandle.jsp">
<hr color="cc00aa">
用戶名: <input type="text" name="user">
<br>
密 碼: <input type="password" name="password">
<br>
<input type="submit" value="登錄">
<input type="reset" name="重置">
</form>
</center>
</body>
</html>
loginhandle頁面：
<%@ page language="java" import="java.sql.*" import="java.util.*,com.ly.model.UserbeanCl" 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>here</title>
</head>
<body>
<center>
<br>
<%
String u = request.getParameter("user");
String p = request.getParameter("password");
// 一、普通驗證
/* if(u.equals("Liyong")&&p.equals("woaini")){
response.sendRedirect("welcome.jsp?user="+u);//跳轉到歡迎界面並傳遞出用戶名user
}
else{
response.sendRedirect("login.jsp");
}
*/
// 二、直接到數據庫中驗證
// DriverManager.registerDriver(new com.mysql.jdbc.Driver());
// Class.forName("com.mysql.jdbc.Driver");
/*
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
Connection ct = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/collage", "root", "");
Statement st = ct.createStatement();
ResultSet rs = st.executeQuery("select password from students where name='"
+ u + "'");
if (rs.next()) {
//說明用戶名存在
if (rs.getString(1).equals(p)) {
//密碼正確
response.sendRedirect("welcome.jsp?user=" + u);//跳轉到歡迎界面並傳遞出用戶名user
} else {
response.sendRedirect("login.jsp");
}
}
rs.close();
st.close();
ct.close();
*/
// 三、通過userbeanCl對用戶進行驗證
UserbeanCl ubc=new UserbeanCl();
if(ubc.checkUser(u,p))
{
response.sendRedirect("welcome.jsp?user=" + u);
}else {
out.println("<script>alert('密碼或者用戶名錯誤！');</script>");
Thread.sleep(1000);
response.sendRedirect("login.jsp");
// return;
}
%>
</center>
</body>
</html>
welcome頁面：
<%@ page language="java" import="java.util.*,com.ly.model.*"
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>Welcome your mother!</title>
</head>
<body>
<center>
Hello,world! <br>
<%=request.getParameter("user")%>
<br> <a href="login.jsp">返回重新登錄</a>
<hr color="silver">
<br> 用戶信息列表 <br>
<%
int pageNow=1;
String u=request.getParameter("user");
String s_pageNow=request.getParameter("pageNow");
if(s_pageNow!=null){
pageNow=Integer.parseInt(s_pageNow);
}
// 調用UserbeanCl的方法，完成分頁顯示
UserbeanCl ubc=new UserbeanCl();
int pageCount=ubc.pageCount();
ArrayList al=ubc.getUsersByPage(pageNow);
%>
<table border="1">
<tr>
<td>用戶Id</td>
<td>姓名</td>
<td>班級</td>
<td>批次</td>
<td>密碼</td>
<td>個性簽名</td>
</tr>
<%
for(int i=0;i<al.size();i++){
Userbean usb=(Userbean)al.get(i);
// System.out.println("-----------------"+usb.getGxqm());
%>
<tr>
<td><%=usb.getId() %></td>
<td><%=usb.getName() %></td>
<td><%=usb.getGrade() %></td>
<td><%=usb.getBatch() %></td>
<td><%=usb.getPassword() %></td>
<td><%=usb.getGxqm() %></td>
</tr>
<%
}
%>
</table>
<br><hr color="blue"><br>
<%
//顯示上一頁
out.println("<a href=welcome.jsp?pageNow="+1+"&user="+u+">首頁</a>");
if(pageNow!=1){
out.println("<a href=welcome.jsp?pageNow="+(pageNow-1)+"&user="+u+">上一頁</a>");
}
// 顯示頁碼
for(int i=pageNow;i<=(pageCount<(pageNow+5)?pageCount:(pageNow+5));i++){
out.println("<a href=welcome.jsp?pageNow="+i+"&user="+u+">["+i+"]</a>");
}
if(pageNow!=pageCount){
out.println("<a href=welcome.jsp?pageNow="+(pageNow+1)+"&user="+u+">下一頁</a>");
}
out.println("<a href=welcome.jsp?pageNow="+pageCount+"&user="+u+">尾頁</a>");
%>
</center>
</body>
</html>
Userbean.java實現數據對象的封裝
package com.ly.model;
public class Userbean {
private int id;
private String name;
private int grade;
private int batch;
private int password;
private String gxqm;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getGrade() {
return grade;
}
public void setGrade(int grade) {
this.grade = grade;
}
public int getBatch() {
return batch;
}
public void setBatch(int batch) {
this.batch = batch;
}
public int getPassword() {
return password;
}
public void setPassword(int password) {
this.password = password;
}
public String getGxqm() {
return gxqm;
}
public void setGxqm(String gxqm) {
this.gxqm = gxqm;
}
}
connDB.java實現數據庫的連接//得到數據庫的連接
//得到數據庫的連接
package com.ly.model;
import java.sql.*;
import java.util.*;
public class connDB {
private Connection ct=null;
public Connection getConn(){
try {
Class.forName("com.mysql.jdbc.Driver");
ct=DriverManager.getConnection("jdbc:mysql://localhost:3306/collage", "root", "");
} catch (Exception e) {
e.printStackTrace();
}
return ct;
}
}
UserbeanCl.java實現業務邏輯的處理
//這是一個處理類，主要封裝對User表的各種操作，包括增刪改查
package com.ly.model;
import java.sql.*;
import java.util.ArrayList;
public class UserbeanCl {
private Statement st = null;
private ResultSet rs = null;
private Connection ct = null;
private int pageSize = 10;
private int rowCount = 0;
private int pageCount = 0;
// 驗證用戶是否存在
public int pageCount() {
try {
// 得到連接
ct = new connDB().getConn();
st=ct.createStatement();
rs = st.executeQuery("select count(*) from students");
//
if(rs.next()){
rowCount=rs.getInt(1);
}
if(rowCount%pageSize==0){
pageCount=rowCount/pageSize;
}else{
pageCount=rowCount/pageSize+1;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
shutup();
}
return pageCount;
}
public ArrayList getUsersByPage(int PageNow) {
pageCount = pageCount();
ct = new connDB().getConn();
int startRow=(PageNow-1)*pageSize;
ArrayList al = new ArrayList();
try {
st = ct.createStatement();
rs=st.executeQuery("SELECT id,name,grade,batch,password,gxqm FROM `students` LIMIT "+startRow+","+pageSize);
while(rs.next()){
Userbean ub=new Userbean();
ub.setId(rs.getInt(1));
ub.setName(rs.getString(2));
ub.setGrade(rs.getInt(3));
ub.setBatch(rs.getInt(4));
ub.setPassword(rs.getInt(5));
ub.setGxqm(rs.getString(6));
// System.out.println(rs.getString(6));
al.add(ub);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
shutup();
}
return al;
}
public boolean checkUser(String u, String p) {
boolean b = false;
ct = new connDB().getConn();
try {
st = ct.createStatement();
ResultSet rs = st
.executeQuery("select password from students where name='"
+ u + "'");
if (rs.next()) {
// 說明用戶名存在
if (rs.getString(1).equals(p)) {
// 密碼正確
b = true;
} else {
return false;
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
shutup();
}
return b;
}
public void shutup() {
try {
if (rs != null)
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
if (st != null)
st.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
if (ct != null)
ct.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
最終現實的簡單分頁效果如圖
