jsp學生資訊管理系統（一）
今天看了java1234網的小鋒老師的jsp實戰專案視訊，做了個簡單的登入驗證，寫的不是很好，有點小問題還沒寫好（密碼或賬號錯誤提示）
資料庫連線類
import java.sql.*;
import java.util.List;public class ConnDB {
private static String URL = "jdbc:mysql://localhost:3306/db_student";//資料庫連線 "db_student"是資料庫名
private static String USER = "root";//資料庫賬號
private static String PASSWORD = "root";//資料庫密碼
private static Connection conn = null;
public ConnDB() {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
//獲取資料庫連線
public Connection getConnction() {
try {
conn = DriverManager.getConnection(URL, USER, PASSWORD);
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
//關閉資料庫連線
public void closeCon(Connection con) throws Exception{
if(con!=null){
con.close();
}
}
//測試連線是否成功
public static void main(String [] args){ConnDB c= new ConnDB();
try{
c.getConnction();
System.out.print("資料庫連線成功");
}catch(Exception e){
e.printStackTrace();
}
}
}
登入介面
用了jQuery框架來驗證是否為空，長度是否足夠。
resetValue()用於清空輸入框的內容。
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
<title>學生資訊管理系統</title>
<script type="text/javascript">
function resetValue(){
document.getElementById("username").value="";
document.getElementById("password").value="";
}
</script>
<script type="text/javascript" src="js/jquery-3.2.1.js"></script>
</head>
<body style="background-color:3a7dce">
<div style="width:1024;height:768;background-image:url(images/login.jpg);margin:0 auto;position:relative">
<div style="position:absolute;left:280px;top:320px">
<form name="form1" method="post" action="login">
<table border="0" cellpadding="5">
<tr><td align="right">賬 號</td>
<td><input type="text" name="username" id="username" value="${uName}" autofocus="autofocus" placeholder="輸入6位的賬號" minlength="6" required="required"></td>
</tr>
<tr><td align="right">密 碼</td>
<td><input type="password" name="password" id="password" value="${pWd}" autofocus="autofocus" placeholder="輸入的密碼" minlength="6" required="required"></td>
</tr>
<tr><td></td><td> <input type="submit" name="submit" value="確定"> <input type="button" name="submit2" value="重置" onClick="resetValue()"></td>
</tr>
</table>
</form>
</div>
</div>
</body>
</html>
寫個javaBean類來當資料載體
public class User {
private int id;
private String username;
private String password;
public User(){
super();
}
public User(String username,String password){
super();
this.username=username;
this.password=password;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
}
資料庫操作類（應該是叫dao層？）
import java.sql.*;
import model.User;
import com.mysql.jdbc.PreparedStatement;
import jdbc_conn.ConnDB;
public class UserchkDao {
public User login(Connection con,User user) throws Exception {
User resultUser=null;
String sql="select * from user where username=? and password=?";
PreparedStatement pstmt=(PreparedStatement) con.prepareStatement(sql);
pstmt.setString(1, user.getUsername());
pstmt.setString(2, user.getPassword());
ResultSet rs=pstmt.executeQuery();
if(rs.next()){
resultUser=new User();
resultUser.setUsername(rs.getString("username"));
resultUser.setPassword(rs.getString("password"));
}
return resultUser;
}
}
寫個servlet
一些邏輯操作，用的是post方式提交表單，所以重寫doPost（）方法。
import java.awt.Window;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import jdbc_conn.ConnDB;
import model.User;
import com.mysql.jdbc.StringUtils;
import dao.UserchkDao;
public class login_check_servlet extends HttpServlet {
ConnDB conndb=new ConnDB();
UserchkDao ucd= new UserchkDao();
/**
* Constructor of the object.
*/
public login_check_servlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print(" This is ");
out.print(this.getClass());
out.println(", using the GET method");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String userName=request.getParameter("username");
String passWord=request.getParameter("password");
request.setAttribute("uName", userName);
request.setAttribute("pWd", passWord);
Connection con=null;
User user=new User(userName,passWord);
try {
con=conndb.getConnction();
User currentUser=ucd.login(con, user);
//User currentUser= new User();
//currentUser=ucd.login(con, user);
if(currentUser==null){
//伺服器跳轉
request.getRequestDispatcher("index.jsp").forward(request, response);
}else{
//客戶端跳轉
response.sendRedirect("calculator.jsp");
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
conndb.closeCon(con);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}