passing value to a jsp page from a java class using DAO

passing value to a jsp page from a java class using DAO - java

I wanted to pass the value retrieved on a java class to a page.I am using DAO classes.
I have retrieved the values from the database and stored them on String variables.Now I want to set them to the text boxes in my view.jsp page.I am new to this area,can anyone help me out??
View.jsp is as
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="process.jsp">
Enter Name <br/> <br> <input type="text" name="uname" onclick="this.value=''"/><br/><br/>
<input type="submit" value="view details"/><br/><br/>
Email id: <br/> <input type="text" name="email" id="email" > <br/><br/>
password: <br/> <input type="text" name="passw" id="passw"><br/><br/>
</form>
</body>
</html>
and My Activity ViewDAO.java is as
public static void view(user u) {
Connection con=ConnectionProvider.getCon();
String uname=u.getUname();
try {
PreparedStatement ps=con.prepareStatement("select email,pass from S1.USER432 where name='"+uname+"'");
ResultSet rs = ps.executeQuery();
while (rs.next()) {
String email = rs.getString("EMAIL");
String pass = rs.getString("PASS");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Thanks...

If you are using a front controller[spring mvc] then you can pass the data by doing,
model.addAttribute("variable_name ", data);
and in the jsp you can access it by doing this ${variable_name};

You need to call the DAO method from your servlet like below:
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// call DAO method to get the email and password
HashMap<String,String> map=ViewDAO.getDetails();
//from the map you will get the email and password.then you need to set them in the attributes and get them in your jsp
request.setAttribute("email", map.get("email"));
request.setAttribute("password", map.get("password"));
}
your DAO method should be like the below:
public static HashMap<String,String> getDetails(user u) {
Connection con=ConnectionProvider.getCon();
String uname=u.getUname();
Map<String,String> map=new HashMap<>();
try {
PreparedStatement ps=con.prepareStatement("select email,pass from S1.USER432 where name='"+uname+"'");
ResultSet rs = ps.executeQuery();
while (rs.next()) {
String email = rs.getString("EMAIL");
String pass = rs.getString("PASS");
}
map.put("email",email);
map.put("password",pass);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return map;
}
}
Hope this will help you.

if you are using simple jsp and servelt, then make one ViewController.java.
You can two methods one for handling GET and other for POST
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
String email = request.getParameter("email");
String password = request.getParameter("password");
request.setAttribute("email", email);
request.setAttribute("password", password);
request.getRequestDispatcher("view.jsp").forward(request, response);
}
catch(Exception e){
}
View.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="process.jsp">
Enter Name <br/> <br> <input type="text" name="uname" onclick="this.value=''"/><br/><br/>
<input type="submit" value="view details"/><br/><br/>
Email id: <br/> <input type="text" name="email" id="email" value="<%=email%>" > <br/><br/>
password: <br/> <input type="text" name="passw" id="passw" value="<%=password%>"><br/><br/>
</form>
</body>
</html>

The Servlet decides which page must be loaded. So whatever you get from the DAO must go to the Servlet and through that, to the jsp. You can use a bean class to send values from DAO to Servlet.
Like this,
public class Details{
private String email;
private String password;
public void setEmail(String email){
this.email = email;
}
public void setPassword(String password){
this.password= password;
}
public String getEmail(){
return this.email;
}
public String getPassword(){
return this.password;
}
}
And you can make the following changes in DAO after getting the query results in the String. Add these
Details d = new Details();
d.setEmail(email);
d.setPassword(pass);
return d;
You can pass this object d to the servlet and retrieve the values using the getter methods of the bean. Also, the DAO must be called from the Servlet.
And now on the Servlet side.
On the Servlet you can put your code in the get or post method depending on your need. It may be like
public class ExampleServlet extends HttpServlet{
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String email = request.getParameter("email"); //got from the jsp where "email" is the name attribute of the input field
Details d = new Details();
d = ViewDao.view(user_object); //the bean sent by DAO. "user_object" is parameter that your DAO method is taking in your code
if(d.getEmail()!=null){ //just an example
// your code that redirects desired page
}
}
}
Based on d returned by the DAO you may redirect to any page you want.

Something like that
Observe this import
dao.UserDao,bean.*,
dao is the package
UserDao is the class
bean is the method you want or is could an attribute from dao
remember that
jsp
<body>
<%#page import="dao.UserDao,bean.*,java.util.*"%>
<%# taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<h1>Users List</h1>
<%
List<User> list=UserDao.getAllRecords();
request.setAttribute("list",list);
%>
<div class="table-responsive">
<table class="table">
<thread class="bg-info">
<th>Id</th><th>Name</th><th>Password</th><th>Edit</th><th>Delete</th>
</thread>
<c:forEach items="${list}" var="u">
<tr>
<td>${u.getId()}</td><td>${u.getUsername()}</td><td>${u.getPassword()}</td>
<td>Edit</td>
<td>Delete</td>
</tr>
</c:forEach>
</table>
</div>
<br/>Add New User
<br>
<br>
<form action="index.jsp">
<button type="submit">IndexUsers</button>
</form>
</body>
Bean or model
package bean;
// classe para as tables
public class User {
private int id;
private String username,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;
}
}
dao
public class UserDao {
public static Connection getConnection(){
Connection con=null;
try{
Class.forName("com.mysql.cj.jdbc.Driver");
con=DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql_database","root","14570");
}catch(Exception e){System.out.println(e);}
return con;
}
public static int save(User u){
int status=0;
try{
Connection con=getConnection();
PreparedStatement ps=con.prepareStatement(
"insert into login(username,password) values(?,?)");
ps.setString(1,u.getUsername());
ps.setString(2,u.getPassword());
status=ps.executeUpdate();
}catch(Exception e){System.out.println(e);}
return status;
}
public static int update(User u){
int status=0;
try{
Connection con=getConnection();
PreparedStatement ps=con.prepareStatement(
"update login set username=?,password=? where id=?");
ps.setString(1,u.getUsername());
ps.setString(2,u.getPassword());
ps.setInt(3,u.getId());
status=ps.executeUpdate();
}catch(Exception e){System.out.println(e);}
return status;
}
public static int delete(User u){
int status=0;
try{
Connection con=getConnection();
PreparedStatement ps=con.prepareStatement("delete from login where id=?");
ps.setInt(1,u.getId());
status=ps.executeUpdate();
}catch(Exception e){System.out.println(e);}
return status;
}
public static List<User> getAllRecords(){
List<User> list=new ArrayList<User>();
try{
Connection con=getConnection();
PreparedStatement ps=con.prepareStatement("select * from login");
ResultSet rs=ps.executeQuery();
while(rs.next()){
User u=new User();
u.setId(rs.getInt("id"));
u.setUsername(rs.getString("username"));
u.setPassword(rs.getString("password"));
list.add(u);
}
}catch(Exception e){System.out.println(e);}
return list;
}
public static User getRecordById(int id){
User u=null;
try{
Connection con=getConnection();
PreparedStatement ps=con.prepareStatement("select * from login where id=?");
ps.setInt(1,id);
ResultSet rs=ps.executeQuery();
while(rs.next()){
u=new User();
u.setId(rs.getInt("id"));
u.setUsername(rs.getString("username"));
u.setPassword(rs.getString("password"));
}
}catch(Exception e){System.out.println(e);}
return u;
}
}

Another Example this import import="dao.*"% makes available any methods from package dao, Bellow you see how to get the result of the method countid() in the dao.
<%#page import="dao.*"%>
<%#page import="java.sql.DriverManager"%>
<%#page import="java.sql.ResultSet"%>
<%#page import="java.sql.Connection"%>
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<% int id = 0; %>
<%
DaoEvento daoEvento = new DaoEvento();
id = daoEvento.countId();
%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap#4.6.1/dist/css/bootstrap.min.css" integrity="sha384-zCbKRCUGaJDkqS1kPbPd7TveP5iyJE0EjAuZQTgFLD2ylzuqKfdKlfG/eSrtxUkn" crossorigin="anonymous">
<body>
<br><br>
<form action="add_event_servletnew" method="POST">
<div class="form-group">
<td>
<font color='green' face = "Arial" size = "4">
<%= request.getParameter("message") %>
</font>
view
<td>
</div>
<div class="form-group">
<label>id</label>
<input type="text" name="id" value="<%= id%>" readonly="readonly" class="form-control"/>
</div>
<div class="form-group">
<label>Title</label>
<input type="text" name="title" value="" class="form-control" />
</div>
<div class="form-group">
<label>Start</label>
<input type="date" name="start" value="" class="form-control"/>
</div>
<div class="form-group">
<label>End</label>
<input type="date" name="end" value="" class="form-control" />
</div>
<div class="form-group">
<td><input type="submit" value="submit" class="btn btn-success btn-block"/></td>
</div>
</form>
</body>
<script src="https://cdn.jsdelivr.net/npm/jquery#3.5.1/dist/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap#4.6.1/dist/js/bootstrap.bundle.min.js" integrity="sha384-fQybjgWLrvvRgtW6bFlB7jaZrFsaBXjsOMm/tB9LTS58ONXgqbR9W8oWht/amnpF" crossorigin="anonymous"></script>
<script src="jquery.mask.min.js"> </script>
</html>

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Error message "The origin server did not find a current representation for the target resource or is not willing to disclose that one exists"

I am currently working on my login and registration page using sublime text. When I try to register users for my registration page or try to login, the error message will pop up shown below.
This is the format for my code shown below:
login.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="loginRegister" method="post">
<table
style="background-image: url('https://static.abbottnutrition.com/cms-prod/abbottfamily.com.sg/img/Article%201%20banner_tcm150-71042.jpg'); width: 500px; height: 200px; margin-left: 20px; margin-left: 20px;">
<tr>
<td><h3 style="color: red;">${message}</h3>
<h3 style="color: green;">${SuccessMessage}</h3></td>
</tr>
<tr>
<td><h3 style="color: Red;">Recipe Login Page</h3></td>
<td></td>
</tr>
<tr>
<td>Email :</td>
<td><input type="text" name="email"></td>
</tr>
<tr>
<td>Password :</td>
<td><input type="password" name="pwd"></td>
</tr>
<tr>
<td><input type="submit" name="submit" value="login"></td>
<td>Registration</td>
</tr>
</table>
</form>
</body>
</html>
register.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="loginRegister" method="post">
<table
style="background-image: url('https://static.abbottnutrition.com/cms-prod/abbottfamily.com.sg/img/Article%201%20banner_tcm150-71042.jpg'); width: 500px; height: 200px; margin-left: 20px; margin-left: 20px;">
<tr>
<td><h3 style="color: Black;">Recipe Registration Page</h3></td>
<td></td>
</tr>
<tr>
<td><h3 style="color: red;">${message}</h3>
<h3 style="color: green;">${SuccessMessage}</h3></td>
</tr>
<tr>
<td>Email :</td>
<td><input type="text" name="email"></td>
</tr>
<tr>
<td>Password :</td>
<td><input type="password" name="pwd"></td>
</tr>
<tr>
<td><input type="submit" name="submit" value="register"></td>
<td>Login</td>
</tr>
</table>
</form>
</body>
</html>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>MyRecipeProject</display-name>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
</web-app>
CustomerDAO.java
public interface CustomerDAO {
public int insertCustomer(Customer c);
public Customer getCustomer(String email,String pwd);
}
Customer.java
public class Customer {
private String email;
private String pwd;
public String getemail() {
return email;
}
public void setemail(String email) {
this.email = email;
}
public String getpwd() {
return pwd;
}
public void setpwd(String pwd) {
this.pwd = pwd;
}
}
LoginRegister.java
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class LoginRegister
*/
#WebServlet("/loginRegister")
public class LoginRegister extends HttpServlet {
private static final long serialVersionUID = 1L;
public LoginRegister() {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
CustomerDAOImpl cd = new CustomerDAOImpl();
String email = request.getParameter("email");
String pwd = request.getParameter("pwd");
String submitType = request.getParameter("submit");
Customer c = cd.getCustomer(email, pwd);
//if (submitType.equals("login") && c!=null && c.getName()!=null)
if (submitType.equals("login") && c!=null && c.getName()!=null) {
request.setAttribute("message", c.getemail());
request.getRequestDispatcher("welcome.jsp").forward(request, response);
} else if (submitType.equals("register")) {
c.setemail(request.getParameter("email"));
c.setpwd(pwd);
cd.insertCustomer(c);
int t = 0;
/*if(cd.insertCustomer(c) > t) {
request.setAttribute("Successmessage", "Registration Done, please login to continue!!!!");
}
else {
request.setAttribute("not successful", "try again");
}
*/
request.setAttribute("SuccessMessage", "Registration Done, please login to continue!!!!");
request.getRequestDispatcher("register.jsp").forward(request, response);
} else {
request.setAttribute("message", "Data Not Found, click on Register !!!");
request.getRequestDispatcher("login.jsp").forward(request, response);
System.out.println(c.getemail());
}
}
}
CustomerDAOImpl.java
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class CustomerDAOImpl implements CustomerDAO {
static Connection con;
static PreparedStatement ps;
public int insertCustomer(Customer c) { //put from frontend data to database
int status = 0;
try {
con = MyConnectionProvider.getConnection();
ps = con.prepareStatement("insert into accountInfo values(?,?)"); // putting data in sql
ps.setString(1, c.getemail()); // before putting into sql, must put user data from frontend to customer object in servlet
ps.setString(2, c.getpwd()); //and then call from here using customer object call and push to database
status = ps.executeUpdate(); //if want to put data, always update
con.close();
} catch (Exception e) {
System.out.println(e);
}
return status;
}
public Customer getCustomer(String email, String pwd) { //call data from database
Customer c = new Customer();
try {
con = MyConnectionProvider.getConnection();
ps = con.prepareStatement("select * from accountInfo where email=? and pwd=?"); //prepare statement to just call all data containing username and password
ps.setString(1, email); //input
ps.setString(2, pwd);
ResultSet rs = ps.executeQuery(); //call from database
while (rs.next()) {
c.setemail(rs.getString(1));
c.setpwd(rs.getString(2)); //get data from database then put into the customer object
}
} catch (Exception e) {
System.out.println(e);
}
return c;
}
}
welcome.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body style="color: yellow;">
<h1>Hi ${message} !!! We welcome you !!!</h1>
</body>
</html>
MyProvider.java
public interface MyProvider {
String username="root"; //password of database
String pwd="xxxx";
String connUrl = "jdbc:mysql://localhost:3306/userinfo?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC"; //postgresql==.mysql
}
MyConnectionProvider.java
import java.sql.*;
public class MyConnectionProvider implements MyProvider {
private static final String DRIVER_NAME = "com.mysql.cj.jdbc.Driver";
// private static final String URL = "jdbc:mysql://localhost:3306/appdb";
// local machine
private static final String URL = "jdbc:mysql://localhost:3306/userinfo?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC";
static {
try {
Class.forName(DRIVER_NAME).newInstance();
} catch (Exception e) {
e.printStackTrace();
}
}
// Establish connection
/**
* Establish connection
*
* #return Connection object
* #throws SQLException throws SQLException
*/
public static Connection getConnection() throws SQLException {
// return DriverManager.getConnection(URL, "root", "yJfcXQETOLH1");
// local machine
System.out.println(DriverManager.getDriver("jdbc:mysql://localhost:3306/userinfo?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC").toString());
return DriverManager.getConnection(URL, "root", "xxxx");
}
// Close connection
/**
* Close connection
*
* #param conn Connection object
* #param stmt Statement object
* #param rs ResultSet object
*/
public static void close(Connection conn, Statement stmt, ResultSet rs) {
try {
if (rs != null) {
rs.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if (stmt != null) {
stmt.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
So basically, I create a folder called myWebProject, and I saved all my codings and pages under a sub-folder called DIPProject as shown below and I run using Tomcat[![][6]
I would appreciate if someone can help me on that. Thanks so much!

Servlet returning blank page not redirecting to jsp page

I am working on a Login and registration form. I have successfully created the Login and Registration form and linked them together. Now I created a separate page for admin where I want to display my database. But I am not able to move to the admin page. Whenever i input my admin credentials it always shows a blank page. I am a newbie both to Java and stackoverflow so I dont know how to ask proper questions. I pasted all my code here. My main problem is in Login.java . I am using eclipse and tomcat 8.5.
Things I have tried till now:-
1) RequestDispatcher rd = request.getRequestDispatcher("/WEB-INF/admin.jsp");
rd.forward(request, response);
2)HttpServletResponse.sendRedirect("/WEB-INF/admin.jsp")
3)response.sendRedirect("WEB_INF/admin.jsp");
Registeration.java
public class Registeration extends HttpServlet {
private static final long serialVersionUID = 1L;
public Registeration(){
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse
response)
throws ServletException, IOException {
}
protected void doPost(HttpServletRequest request, HttpServletResponse
response)
throws ServletException, IOException{
try {
String usernam = request.getParameter("usernam");
String password = request.getParameter("password");
String age = request.getParameter("age");
String gender = request.getParameter("gender");
String event = request.getParameter("event");
String sql = "insert into
registeration(usernam,password,age,gender,event) values(?,?,?,?,?)";
Class.forName("com.mysql.jdbc.Driver");
Connection conn =
DriverManager.getConnection("jdbc:mysql://localhost:3306/portal",
"root", "");
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1,usernam);
ps.setString(2,password);
ps.setString(3,age);
ps.setString(4,gender);
ps.setString(5,event);
ps.executeUpdate();
PrintWriter out = response.getWriter();
out.println("You have successfully registered!");
out.flush();
RequestDispatcher rd = request.getRequestDispatcher("login.jsp");
rd.include(request, response);
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
}
}
Registeration.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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>JSP Page</title>
<style>
img {
display: block;
margin-left: auto;
margin-right: auto;
}
</style>
</head>
<img src="unilogo.PNG" style="width:40%">
<body>
<div align="center">
<form action="Registeration" method="POST">
User Name:<input type="text" name="usernam" required="required">
<br>
Password : <input type="password" name="password"
required="required"><br>
Age : <input type="text" name="age" required="required" /><br>
Gender : <select name="gender">
<option>Male</option>
<option>Female</option>
<option>Transgender</option>
</select><br>
Event : <select name="event" multiple="multiple">
<option>Mr.Tanwar Body Building</option>
<option>Fashion Show</option>
<option>Dance</option>
<option>Singing</option>
<option>Coding</option>
</select><br>
<input type="submit" value="REGISTER" />
<input type="reset" value="RESET" /><br>
<a href="${pageContext.request.contextPath}/login.jsp">Click
here
to go to the login page</a>
</form>
</div>
</body>
</html>
Login.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Login Page</title>
</head>
<body>
<div align="center">
<form action="Login" method="POST">
User Name:<input type="text" name="usernam" required="required">
<br>
Password : <input type="password" name="password"
required="required"><br>
<input type="submit" value="Login" />
<input type="reset" value="RESET" /><br>
<a
href="${pageContext.request.contextPath}/registeration.jsp">Click here
to
go to the Registration page</a>
</form>
</div>
</body>
</html>
Login.java
public class Login extends HttpServlet {
private static final long serialVersionUID = 1L;
public Login() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException {
}
protected void doPost(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException {
try {
String usernam = request.getParameter("usernam");
String password = request.getParameter("password");
String dbName = null;
String dbPassword = null;
String sql = "select * from registeration where usernam =
? and password = ?";
Class.forName("com.mysql.jdbc.Driver");
Connection conn =
DriverManager.getConnection("jdbc:mysql://localhost:3306/portal",
"root",
"");
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1,usernam);
ps.setString(2,password);
ResultSet rs = ps.executeQuery();
PrintWriter out = response.getWriter();
while(rs.next()){
dbName = rs.getString(2);
dbPassword = rs.getString("password");
if(usernam.equals("admin") &&
password.equals("password")){
RequestDispatcher rd =
request.getRequestDispatcher("/WEB-INF/admin.jsp");
rd.forward(request, response);
}
if(usernam.equals(dbName) &&
password.equals(dbPassword)) {
out.println("You have successfully logged
in!");
out.println("Age:"+rs.getString(4)+"
Gender:"+rs.getString(5)+" Event:"+rs.getString(6));
}
else {
RequestDispatcher rd =
request.getRequestDispatcher("/WEB-INF/registeration.jsp");
rd.forward(request, response);
}
}
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID"
version="3.1">
<display-name>Registeration</display-name>
<servlet>
<servlet-name>reg</servlet-name>
<servlet-class>jdbc.registeration</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>reg</servlet-name>
<url-pattern>/regServlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>login</servlet-name>
<servlet-class>jdbc.Login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/loginServlet</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>30</session-timeout>
</session-config>
</web-app>
My login page is supposed to redirect me to admin.jsp when i enter my admin details. But all i get is a blank page. My url after entering admin details"http://localhost:8080/Registeration/Login". I am getting the required output when enter the login id which are stored in DB.

Spring thymeleaf give error in post request

I have this simple code: This is my controller class where i redirecting to a page
#Controller
public class SimpleController {
#GetMapping("/nuovo-utente")
public String viewInserisciUtente(Model model){
model.addAttribute("nuovoUtente", new Utente());
return "nuovo-utente";
}
#PostMapping("/nuovo-utente")
public void memorizzaUtente(#ModelAttribute Utente utente){
System.out.println(utente.getId());
}
}
This is model class.
public class Utente {
private String id=null;
private String citta=null;
private String genere=null;
private String data_nascita=null;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getCitta() {
return citta;
}
public void setCitta(String citta) {
this.citta = citta;
}
public String getGenere() {
return genere;
}
public void setGenere(String genere) {
this.genere = genere;
}
public String getData_nascita() {
return data_nascita;
}
public void setData_nascita(String data_nascita) {
this.data_nascita = data_nascita;
}
}
and My html page with thymeleaf is like :
<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>Inserisci un nuovo utente</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<h1>Form</h1>
<form action="#" th:action="#{/nuovo-utente}" th:object="${nuovoUtente}" method="post">
<p>Id: <input type="text" th:field="*{id}" /></p>
<p>Città: <input type="text" th:field="*{citta}" /></p>
<p>Genere: <input type="text" th:field="*{genere}" /></p>
<p>Data nascita: <input type="text" th:field="*{data_nascita}" /></p>
<p><input type="submit" value="Submit" /> <input type="reset" value="Reset" /></p>
</form>
</body>
</html>
So, as I said into the title, this simple code for a form give me error when I try to submit the form by post request. The error is the above:
Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "nuovo-utente" - line 10, col 32)
What can you say to me? Some help will be appreciate

You have to use diferent html and urls. One to create the form and another one to submit the form. You are using the same url.

First of all in your html page change
<html xmlns:th="http://www.thymeleaf.org">
to
<html xmlns:th="http://www.w3.org/1999/xhtml">
And write your controller class like
#PostMapping("/nuovo-utente")
public String memorizzaUtente(#ModelAttribute("nuovoUtente") Utente utente) {
System.out.println(utente.getId());
return "any page";
}
}

JavaBean not being remembered throughout the session

I'm currently learning JSP/Servelets. The following is code containing 2 JSP pages and a servlet, which works as follows:
JSP #1 requests user info, & passes it into a servlet.
The servlet Instantiates a JavaBean class, and passes it to the 2nd JSP, using the Session Object.
The 2nd JSP then displays the info that th user entered in the 1st JSP; the user can then hit the Return button to return to the 1st JSP.
My Question is: I've read in various Tutorials (notably Murach's JSP, which this code is based on) that if the Javabean attributes are passed to the session object rather than the request object, the JavaBean's values should be maintained throughout the session. However when I return to the first page, the JB fields are empty. Am i doing anything wrong? I would appreciate any help!
The following is the code:
1st JSP:
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Email Application</title>
</head>
<body>
<h1>Join our Email list</h1>
<p>To join our email list, enter your name and email address below.<br>
Then, click on the Submit button</p>
<form action="addToEmailList" method="post">
<jsp:useBean id="user" scope="session" class="business.User"/>
<table cellspacing="5" border="0">
<tr>
<td align="right">First name:</td>
<td>
<input type="text" name="firstName"
value = "<jsp:getProperty name="user" property="firstName"/>">
</td>
</tr>
<tr>
<td align="right">Last name:</td>
<td><input type="text" name="lastName"
value = "<jsp:getProperty name="user" property="lastName"/>">
</td>
</tr>
<tr>
<td align="right">Email address:</td>
<td><input type="text" name="emailAddress"
value = "<jsp:getProperty name="user" property="emailAddress"/>">
</td>
</tr>
<tr>
<td>I'm interested in these types of music:</td>
<td><select name="music" multiple>
<option value="rock">Rock</option>
<option value="country">Country</option>
<option value="bluegrass">Bluegrass</option>
<option value="folkMusic">Folk Music</option>
</select>
</td>
</tr>
<tr>
<td ></td>
<td><input type="submit" name="Submit"></td>
</tr>
</table>
</form>
</body>
Servlet:
public class AddToEmailListServlet extends HttpServlet
{
private static final long serialVersionUID = 1L;
private HttpServletRequest request;
private HttpServletResponse response;
private String firstName;
private String lastName;
private String emailAddress;
private String[] musicTypes;
private Music music;
private User user;
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException
{
this.request = request;
this.response = response;
setInstanceVariables();
writeDataToFile();
forwardResponseToJSPpage();
System.err.println("Hello!");
}
private void setInstanceVariables()
{
this.firstName = getFirstName();
this.lastName = getLastName();
this.emailAddress = getEmailAddress();
this.musicTypes = request.getParameterValues("music"); //getMusic();
this.user = new User(firstName,lastName,emailAddress);
}
private String getFirstName()
{
return request.getParameter("firstName");
}
private String getLastName()
{
return request.getParameter("lastName");
}
private String getEmailAddress()
{
return request.getParameter("emailAddress");
}
private void writeDataToFile() throws IOException
{
String path = getRelativeFileName();
UserIO.add(user,path);
}
private String getRelativeFileName()
{
ServletContext sc = getServletContext();
String path = sc.getRealPath("/WEB-INF/EmailList.txt");
return path;
}
private void forwardResponseToJSPpage() throws ServletException, IOException
{
if(this.emailAddress.isEmpty()||this.firstName.isEmpty()||this.lastName.isEmpty())
{
String url = "/validation_error.jsp";
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher(url);
dispatcher.forward(request,response);
}
else
{
music = new Music(musicTypes);
HttpSession session = this.request.getSession();
session.setAttribute("music", music);
session.setAttribute("user", user);
String url = "/display_email_entry.jsp";
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher(url);
dispatcher.forward(request,response);
}
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException
{
doPost(request,response);
}
}
2nd JSP:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%# include file="/header.html" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Email Application</title>
</head>
<body>
<h1>Thanks for joining our email list</h1>
<p>Here is the information that you entered:</p>
<jsp:useBean id="user" scope="session" class="business.User"/>
<table cellspacing="5" cellpadding="5" border="1">
<tr>
<td align="right">First name:</td>
<td><jsp:getProperty name="user" property="firstName"/></td>
</tr>
<tr>
<td align="right">Last name:</td>
<td><jsp:getProperty name="user" property="lastName"/></td>
</tr>
<tr>
<td align="right">Email Address:</td>
<td><jsp:getProperty name="user" property="emailAddress"/></td>
</tr>
</table>
<p>We'll use the Email to otify you whenever we have new releases of the following types of music:</p>
<c:forEach items="${music.musicTypes}" var="i">
<c:out value="${i}"></c:out><br/>
</c:forEach>
<p>To enter another email address, click on the Back <br>
button in your browser or the Return button shown <br>
below.</p>
<form action="join_email_list.jsp" method="post">
<input type="submit" value="Return">
</form>
</body>
<%# include file="/footer.html" %>
</html>

unable to update table using JSP/DAO/Servlet

Hello i'm trying to create a page to update a row in my database table i'm using DAO/Servlet with JSP page
DAO code:
public static AnimalUpdateBean updateAnimal(AnimalUpdateBean bean) {
//preparing some objects for connection
PreparedStatement up = null;
Statement stmt = null;
String id = bean.getAnimalId();
String aname = bean.getAnimalName();
String dob = bean.getAnimalDob();
String gender = bean.getAnimalGender();
String breedid = bean.getAnimalBreed();
String remark = bean.getAnimalRemark();
try
{
//connect to DB
currentCon = dbConnection.getConnection();
up = currentCon.prepareStatement("update animal set aname = '"+aname+"' , gender = '"+gender+"', specie_id = '"
+breedid+"' , remark = '"+remark+"' where animal_id = '"+id+"'");
up.executeUpdate();
if (up.executeUpdate()>=1){
stmt=currentCon.createStatement();
rs = stmt.executeQuery("select aname , dob, gender, specie_id , remark from animal where animal_id = '"+id+"'");
}
System.out.println("done");
}
catch (Exception ex)
{
System.out.println("Log In failed: An Exception has occurred! " + ex);
}
//some exception handling
finally
{
if (rs != null) {try {rs.close();} catch (Exception e) {} rs = null;}
if (stmt != null) {try {stmt.close();} catch (Exception e) {}stmt = null;}
if (currentCon != null) {try {currentCon.close();} catch (Exception e) {}currentCon = null;}
}
return bean;
}
}
UpdateAnimal.jsp code:
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%# page import="java.util.ArrayList" %>
<%#page import="content.*"%>
<%#page import="java.sql.*"%>
<%#page import="java.util.*"%>
<%# page session="true"%>
<%#page import="java.io.*"%>
<%#page import="java.net.*"%>
<%#page import="javax.servlet.*"%>
<%# page language="java"
contentType="text/html; charset=windows-1256"
pageEncoding="windows-1256" %>
<!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=windows-1256">
<title>Update Animal</title>
<link rel="stylesheet"
href="./css/styles.css"
type="text/css"/>
</head>
<body>
<table class="title">
<tr><th>Zoo keeper</th></tr>
</table>
<h1>Update Animal</h1>
<form action="Relay" >
<fieldset>
Animal new name: <input type= "text" name = "aname"><br>
Animal new DOB: <input type= "text" name = "dob"><br>
<br>
Animal new gender:
<select name="gender" id="gender">
<option value="male">Male</option>
<option value="female">Female</option>
</select>
<br>
Animal new Breed: <input type= "text" name = "breedid" ><br>
Animal new remarks: <textarea name = "remark" rows="4" cols="20">
</textarea> <br /> <br/>
<input type="submit" value="submit">
<input type="hidden" name="animal_id" value="<%= request.getParameter("animal_id") %>">
<input type="hidden" name="command" value="UpdateAnimalServlet" >
</fieldset>
</form>
</body></html>
the record being updated come from a select page to view the records when the user click on the name he will be redirected to update page CheckAnimal.jsp
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%# page import="java.util.ArrayList" %>
<%#page import="content.*"%>
<%#page import="java.sql.*"%>
<%#page import="java.util.*"%>
<%# page session="true"%>
<%#page import="java.io.*"%>
<%#page import="java.net.*"%>
<%#page import="javax.servlet.*"%>
<%# page language="java"
contentType="text/html; charset=windows-1256"
pageEncoding="windows-1256" %>
<!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=windows-1256">
<title>Animal list</title>
<link rel="stylesheet"
href="./css/styles.css"
type="text/css"/>
</head>
<body>
<table class="title">
<tr><th>Zoo keeper</th></tr>
</table>
<h1>Animal list</h1>
Click on animal name to update it!
<center>
<table width="100 % " id='table1' border="1" cellspacing="2" cellpadding="2">
<tr class="tab-highlighted-2">
<td class="tab-highlighted-2" width="15">
<div align="left">Name</div>
</td>
<td class="tab-highlighted-2" width="13">
<div align="left">Age</div>
</td>
<td class="tab-highlighted-2" width="13">
<div align="left">Gender</div>
</td>
<td class="tab-highlighted-2" width="13">
<div align="left">Status</div>
</td>
<td class="tab-highlighted-2" width="13">
<div align="left">Breed</div>
</td>
<td class="tab-highlighted-2" width="13">
<div align="left">Pen #</div>
</td>
<td class="tab-highlighted-2" width="15">
<div align="left">Zoo</div>
</td>
<td class="tab-highlighted-2" width="20">
<div align="left">Remarks</div>
</td>
</tr>
<c:forEach items="${beans}" var="view">
<tr>
<td>${view.animalName}</td>
<td>${view.animalDob}</td>
<td>${view.animalGender}</td>
<td>${view.animalSource}</td>
<td>${view.animalBreed}</td>
<td>${view.sectionId}</td>
<td>${view.zooId}</td>
<td>${view.animalRemark}</td>
</tr>
</c:forEach>
</table>
</center>
</body></html>
AnimalUpdateBean.java code:
package content;
public class AnimalUpdateBean {
private String animalId;
private String animalName;
private String animalDob;
private String animalGender;
private String animalBreed;
private String animalRemark;
public String getAnimalId() {return animalId;}
public String getAnimalName() {return animalName;}
public String getAnimalDob() {return animalDob;}
public String getAnimalGender() {return animalGender;}
public String getAnimalBreed() {return animalBreed;}
public String getAnimalRemark() {return animalRemark;}
public void setAnimalId(String animalId) {this.animalId = animalId;}
public void setAnimalName(String animalName) {this.animalName = animalName;}
public void setAnimalDob(String animalDob) {this.animalDob = animalDob;}
public void setAnimalGender(String animalGender) {this.animalGender = animalGender;}
public void setAnimalBreed(String animalBreed) {this.animalBreed = animalBreed;}
public void setAnimalRemark(String animalRemark) {this.animalRemark = animalRemark;}
}
the servlet responsible to start the update is UpdateAnimalServlet:
package content;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class LoginServlet
*/
public class UpdateAnimalServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, java.io.IOException {
try
{
AnimalUpdateBean animal = new AnimalUpdateBean();
animal.setAnimalId(request.getParameter("animal_id"));
animal.setAnimalName(request.getParameter("aname"));
// animal.setAnimalDob(request.getParameter("dob"));
animal.setAnimalGender(request.getParameter("gender"));
animal.setAnimalBreed(request.getParameter("breedid"));
animal.setAnimalRemark(request.getParameter("remark"));
String test = request.getParameter("animal_id");
System.out.println(test);
System.out.println(animal);
animal = DAO.updateAnimal(animal);
response.sendRedirect("/oosd/member.jsp");
}
catch (Throwable theException)
{
System.out.println(theException);
}
}
}
I'm using a Relay servlet that calls AnimalUpdateServlet for execution:
package content;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class LoginServlet
*/
public class Relay extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, java.io.IOException {
try
{
String command = request.getParameter("command");
if (command.equals("LoginServlet")){
RequestDispatcher rd =request.getRequestDispatcher("/"+command);
rd.forward(request, response);
//for testing
System.out.println("Request forwarded to " + command + " servlet");
} else if (command.equals("UpdateAnimalServlet")){
RequestDispatcher rd =request.getRequestDispatcher("/"+command);
rd.forward(request, response);
//for testing
System.out.println("Request forwarded to " + command + " servlet");
}
else
System.out.println("=> command='" + command + "'");
String url = "/oosd/" + command;
String encodedUrl = response.encodeRedirectURL(url);
System.out.println(" url=" + url);
System.out.println(" encodedUrl=" + encodedUrl);
response.sendRedirect(encodedUrl);
}
catch (Throwable theException)
{
System.out.println(theException);
}
}
}
and last thing is the web.xml page:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:javaee="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>content.LoginServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>UpdateAnimalServlet</servlet-name>
<servlet-class>content.UpdateAnimalServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>SelectAnimalServlet</servlet-name>
<servlet-class>content.SelectAnimalServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>Relay</servlet-name>
<servlet-class>content.Relay</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>SelectAnimalServlet</servlet-name>
<url-pattern>/SelectAnimalServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>UpdateAnimalServlet</servlet-name>
<url-pattern>/UpdateAnimalServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Relay</servlet-name>
<url-pattern>/Relay</url-pattern>
</servlet-mapping>
</web-app>
I keep getting these errors:
Log In failed: An Exception has occurred! java.sql.SQLException: [Microsoft][ODBC Microsoft Access Driver] Data type mismatch in criteria expression.
java.lang.IllegalStateException: Cannot call sendRedirect() after the response has been committed
I have checked the data entry and all correct name text, gender text, specie_id number, remark text i even put the dob on hold until this work i'm using access database and here is the connection code:
package content;
import java.sql.*;
public class dbConnection {
static Connection con;
static String url;
public static Connection getConnection()
{
try
{
String url = "jdbc:odbc:oosd";
// assuming "DataSource" is your DataSource name
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
try
{
con = DriverManager.getConnection(url,"","");
// assuming your SQL Server's username is "username"
// and password is "password"
}
catch (SQLException ex)
{
ex.printStackTrace();
}
}
catch(ClassNotFoundException e)
{
System.out.println(e);
}
return con;
}
}
Any idea where is my mistake here ?

as specie_id is a number and that's what the thrown exception is stating "Data type mismatch in criteria expression." and because of this exception sendRedirect error is occuring as because of the SQLException data has been already written to the response.
your query should be something like
"update animal set aname = '"+aname+"' , gender = '"+gender+"', specie_id = "
+Integer.parseInt(breedid)+" , remark = '"+remark+"' where animal_id = '"+id+"'"
same would be required if animal_id is also a number.

The sendRedirect error happens when you've already written data to the response (like with a forward, or to the JSP writer directly) then try to redirect.
The SQL error is likely due to you using a string IDs in the SQL (surrounded by single-quotes) whereas the IDs in the DB are most likely defined as an integer.
Also, after you update the animal, you perform a query, but do nothing with the results.

We Keep Coding

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

passing value to a jsp page from a java class using DAO - java

If you are using a front controller[spring mvc] then you can pass the data by doing, model.addAttribute("variable_name ", data); and in the jsp you can access it by doing this ${variable_name};

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