Delete a record from database using servlet - java

The Remove.java is the servlet and the index.jsp is the jsp file. I am trying to delete the file using email,since it is unique.
Remove.java
package servletPool;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet("/Remove")
public class Remove extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String uEmail = request.getParameter("email");
try {
Class.forName("com.mysql.jdbc.Driver");
String user = "root";
String pass = "root";
String query = "delete from user_details where email=?";
Connection con = DriverManager.getConnection("jdbc:mysql://locahost:3306/dbname", user, pass);
PreparedStatement ps = con.prepareStatement("delete from user_details where email=?");
ps.setString(1, uEmail);
int i = ps.executeUpdate();
if(i > 0) {
out.println("User successfully removed...");
}
} catch (Exception e) {
System.out.println(e);
}
}
}
and here is the index.jsp file from which the record will be deleted.
index.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>Registration Page.</title>
</head>
<body>
<div>
<div style="padding : 10px;">
<center>
<form action="Remove.servlet" method="get">
<h5>If you want to remove users,</h5>
<input type="email" placeHolder="User's Email" name="email"/>
<input type="button" value="Click" name="remove"/>
</form>
</center>
</div>
</center>
</div>
</body>
</html>

Try changing from:
<form action="Remove.servlet" method="get">
to:
<form action="Remove" method="post">
and from:
<input type="button" value="Click" name="remove"/>
to:
<input type="submit" value="Click" name="remove"/>
In addition, line 26 (</center>) in index.jsp and line 29 (String query = "delete from user_details where email=?";) in Remove.java should be removed because they are unnecessary.

Related

Problem with insert data into Derby database

Problem with insert data into Derby database
I use jsp and servlet, but I have try so many time but still can not insert data into database, it only shows
List of students with score:
and nothing else, it should insert user input into database, database connection is set, id data type is number , marks is int, name is varchar. No error in program I also add javaDB Driver to Libraries, I just do not understand what is wrong.
index.jsp
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Student Score</title>
</head>
<body>
<h1>Welcome to Student Score Application</h1>
<form method="post" action="Result.jsp">
<input type="submit" value="View Data">
</form>
<br>
<form method="post" action="servletAdd">
ID:<input type="text" name="ID"><br>
Name:<input type="text" name="name"><br>
Marks:<input type="text" name="marks"><br>
<input type="submit" value="Add">
<input type="reset" value="Clear">
</form>
</body>
</html>
Result.jsp
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Result</title>
</head>
<body>
<h1>List of students with score:</h1>
<%#page import="java.sql.*"%>
<%
Class.forName("org.apache.derby.jdbc.ClientDriver");
Connection con = DriverManager.getConnection("jdbc:derby://localhost:1527/abc","abc","abc");
Statement stmt = con.createStatement();
String sql = "SELECT * FROM ABC";
ResultSet rs = stmt.executeQuery(sql);
while(rs.next()){
String id = rs.getString("id");
String name = rs.getString("name");
int marks = rs.getInt("marks");
out.println("ID: "+ id);
out.println("Name: "+name);
out.println("Marks: "+marks);
%><br>
<%
}
//STEP 6:
rs.close();
stmt.close();
con.close();
%>
</body>
</html>
servletAdd.java
import java.sql.*;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.annotation.WebServlet;
public class servletAdd extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String JDBC_DRIVER = "org.apache.derby.jdbc.ClientDriver";
String DB_URL = "jdbc:derby://localhost:1527/abc";
String USER ="abc";
String PASS ="abc";
Connection conn = null;
Statement stmt = null;
String id = request.getParameter("ID");
String name = request.getParameter("name");
int marks = Integer.parseInt(request.getParameter("marks"));
try{
Class.forName(JDBC_DRIVER);
conn = DriverManager.getConnection("jdbc:derby://localhost:1527/abc",USER,PASS);
stmt = conn.createStatement();
String sql = "INSERT into ABC values"+"("+ "'"+ id +"'"+ ","+ name + ","+ "'"+ marks+"'"+")";
stmt.executeUpdate(sql);
stmt.close();
conn.close();
}catch(Exception e){
e.printStackTrace();
}
response.setContentType("text/html;charset=UTF-8");
response.sendRedirect(request.getContextPath()+"/Result.jsp");
}
}

JSP & Servlet & Maven: form attribute "action" redirects to another jsp page, instead of sendRedirect method

I have created a login form in my index.jsp file:
<%# page contentType="text/html; ISO-8859-1" language="java" %>
<html>
<head>
<title>Material Master Data Manager</title>
<meta charset="ISO-8859-1">
<link rel="stylesheet" href="css/login_style.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
</head>
<body>
<div id="basicData">
<div id="createMaterialHeader">
<h2><i><b>Material Master Data Manager</b></i></h2>
<div id="newPasswordBar">
<p>New Password</p>
</div>
</div>
<form class="tabcontent" action="MaterialCreator" method="post">
<label for="client">Client</label><br>
<select type="text" name="client" id="client">
<option>Commerzbank AG S.A. Branch in Lodz</option>
<option>Daikin Airconditioning Poland Sp. z o.o.</option>
<option>Infosys Consulting</option>
</select><br>
<label for="userID">User ID</label><br>
<input type="text" id="userID" name="userID"><br>
<label for="userPassword">Password</label><br>
<input type="password" id="userPassword" name="userPassword"><br>
<label for="isAdmin">Admin</label><br>
<input type="text" id="isAdmin" name="isAdmin"><br>
<input type="submit" class="fa fa-check">
</form>
</div>
</div>
<footer>
<p><a>© Created by Lorem Ipsum. 2017</a></p>
</footer>
</body>
<script src='javaScript/loginJs.js'></script>
</html>
That is MaterialCreator servlet:
package com.mmdmanager;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
#WebServlet("/MaterialCreator")
public class MaterialCreator extends HttpServlet {
Connection dbConnection;
PreparedStatement getCredentialsFromDb;
ResultSet userCredentialsReceived;
String userCredentials = "SELECT USER_ID, FIRST_NAME, LAST_NAME, SEX, COMPANY_NAME, IS_ADMIN, ACC_PASSWORD FROM USERS " +
"WHERE COMPANY_NAME =? AND USER_ID =? AND ACC_PASSWORD =? AND IS_ADMIN =?";
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//response.getWriter().append("Served at: ").append(request.getContextPath());
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter printWriter = response.getWriter();
doGet(request,response);
String company_name = request.getParameter("client");
String user_id = request.getParameter("userID");
String acc_password = request.getParameter("userPassword");
String is_admin = request.getParameter("isAdmin");
if (company_name.equals("Infosys Consulting") && user_id.equals("ADMIN1") && acc_password.equals("Q#3wertyuiop") && is_admin.equals("Y")) {
response.sendRedirect("MaterialCreator.jsp");
}
else {
response.sendRedirect("");
}
}
}
As You can see in the code above, the main idea is to redirect on condition that a user provides correct credentials (IF statement stores it). Unfortunately, no matter what credentials I provide, every time when I click the input button (class "fa fa-check") I am redirected to MaterialCreator servlet, not to MaterialCreator.jsp file, however the code contains method -> response.sendRedirect("MaterialCreator.jsp");, but it is invisible for the project.
MaterialCreator.jsp file has a very simple html code:
<%# page contentType="text/html; ISO-8859-1" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h1>Hello User!</h1>
</body>
</html>

Why am I getting a blank page in my servlet program

I am using netbeans 8.2 and using Apache Tomcat server. Whenever I run the program I get to the registration page. But when I submit the information I am supposed to get an output. But I always get a blank page.I am using the database present in JAVA. Please Help I have to submit my java project;_;. I still need to create a login page.
Thanks in Advance.
Jsp Program
<%--
Document : registeration
Created on : Mar 12, 2019, 10:24:50 AM
Author : Pranav Sharma
--%>
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<div align="center">
<form action="Registeration" method="POST">
User Name:<input type="text" name="user" 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" />
</form>
</div>
</body>
Servlet Program
package jdbc;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet(name="Registeration", urlPatterns={"/Registeration"})
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 name = request.getParameter("user");
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(name,password,age,gender,event) values(?,?,?,?,?)";
Class.forName("org.apache.derby.jdbc.ClientDriver");
Connection conn = DriverManager.getConnection("jdbc:derby://localhost:1527/RegForm","pranav","sharma");
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1,name);
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!");
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
}
}
Web-xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
<servlet>
<servlet-name>Registeration</servlet-name>
<servlet-class>jdbc.Registeration</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Registeration</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
I have create a java-servlet project which uses sql server as a database. Underline project takes input from the ui and persist into database.
After inserting data into database, it will show up is records inserted successfully or not.
Change the DBConnectionUtils according to your database
String url = "jdbc:mysql://localhost:3306/";
String dbName = "root";
String driver = "com.mysql.jdbc.Driver";
This is the link for the project on github https://github.com/rosmahajan/java-servlet
Otherwise please post more information like any exception or error you are getting to investigate what is wrong with your code.
Hope this helps you !!

Using JSP to store images in Mysql and upload the images online

I am still wondering what it is that i am doing wrong,my problem is i dont know if it is my entire sample code which has na error or my connection to the database which has an issues, as of where i stand i am not sure what is making me get this error. (displayed below).I have tried to look here at stack overflow but all i get is loading images using JSP but not adding them to the database. If we have one i couldnt trace please help me with the link. I have included all the libraries needed and my code has no error apart from this output. I came here because i am stranded and need a short review of what you proffesionals think is wrong with my code as done below. I will really appreciate anyhelp given as i am working on a deadline.
my Database name is
AppDB
I was wondering should i use the name of the table? to INSERT INTO? which is
'contacts'
Error Message
HTTP Status 404 - /UploadImageOnWeb/uploadServlet type Status report
message /UploadImageOnWeb/uploadServlet description The requested
resource is not available. Apache Tomcat/8.0.23
Thank you
Java Servlet Code
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
/**
* Servlet implementation class FileUploadDBServlet
*/
#MultipartConfig(maxFileSize = 16177215)
#WebServlet("/FileUploadDBServlet")
public class FileUploadDBServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
// database connection settings
/*private String dbURL = "jdbc:mysql://localhost/AppDB";
private String dbUser = "root";
private String dbPass = "mypassword";*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String firstName = request.getParameter("firstName");
String lastName = request.getParameter("lastName");
InputStream inputStream = null;
Part filePart = request.getPart("photo");
if (filePart != null) {
System.out.println(filePart.getName());
System.out.println(filePart.getSize());
System.out.println(filePart.getContentType());
inputStream = filePart.getInputStream();
}
Connection conn = null;
String message = null;
try {
// connects to the database
/*DriverManager.registerDriver("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(dbURL, dbUser, dbPass);*/
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost/AppDB","root","mypassword");
// constructs SQL statement
String sql = "INSERT INTO contacts (first_name, last_name, photo) values (?, ?, ?)";
PreparedStatement statement = conn.prepareStatement(sql);
statement.setString(1, firstName);
statement.setString(2, lastName);
if (inputStream != null) {
// fetches input stream of the upload file for the blob column
statement.setBlob(3, inputStream);
}
int row = statement.executeUpdate();
if (row > 0) {
message = "File uploaded and saved into database";
}
} catch (SQLException ex) {
message = "ERROR: " + ex.getMessage();
ex.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (conn != null) {
// closes the database connection
try {
conn.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
}
// sets the message in request scope
request.setAttribute("Message", message);
// forwards to the message page
getServletContext().getRequestDispatcher("/Message.jsp").forward(request, response);
}
}
}
My .Jsp class
<%# 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>File Upload to Database Demo</title>
</head>
<body>
<center>
<h1>File Upload to Database Demo</h1>
<form method="post" action="uploadServlet" enctype="multipart/form-data">
<table border="0">
<tr>
<td>Enter First Name: </td>
<td><input type="text" name="firstName" size="20"/></td>
</tr>
<tr>
<td>Enter Last Name: </td>
<td><input type="text" name="lastName" size="20"/></td>
</tr>
<tr>
<td>Portrait Photo: </td>
<td><input type="file" name="photo" size="20"/></td>
</tr>
<tr>
<td colspan="2">
<input type="submit" value="Save">
</td>
</tr>
</table>
</form>
</center>
</body>
</html>
Display 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>Message</title>
</head>
<body>
<center>
<h3><%=request.getAttribute("Message")%></h3>
</center>
</body>
</html>
The 404 error indicates that the form is not even getting to the servlet.
You defined the action attribute in the form as uploadServlet which doesn't seem to be a valid URL for your application.
The servlet's URL is defined in the #WebServlet annotation as FileUploadDBServlet.
So you can fix it by changing the action in the form or changing the URL for the servlet.

Can't call doPost() method of servlet in jsp page [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 7 years ago.
At beggining. There is a application structure.
I have 3 MySQL tables ( Obiekt, Termin, Rezerwacja). In project i have jsp page (here is code) :
<%# page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%# page import="java.sql.*"%>
<%# page import="java.io.*"%>
<%# page import="java.util.*"%>
<%# page import="test.Obiekt"%>
<%# page import="test.ListaObiektow"%>
<%# page import="test.Termin"%>
<%# page import="test.ListaTerminow"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>menu główne</title>
<meta name="viewport" content="initial-scale=1, maximum-scale=1">
<meta name="android-mobile-web-app-capable" content="yes">
<meta name="android-mobile-web-app-status-bar-style" content="black">
<link href="css/ratchet.css" rel="stylesheet">
<link href="css/ratchet-theme-android.css" rel="stylesheet">
<script src="js/ratchet.js"></script>
<script type="text/javascript">
function Refresh(idObiekt){
location.href="pilkaNozna.jsp?idObiekt=" + idObiekt;
}
</script>
</head>
<body>
</br>
</br>
</br>
<header class="bar bar-nav">
<a class="icon icon-left-nav pull-left" href="wyszukaj.jsp"></a>
<h1 class="title">Wybierz obiekt</h1>
</header>
<div id="content">
<div class="tabelawybor">
<b>Wybierz obiekt:</b>
<%
ArrayList<Obiekt> list = new ListaObiektow().getObiekty();
%>
<form>
<select name="obiekt" onChange="Refresh(this.value)">
<option value="0" selected>Wybierz Obiekt</option>
<%
String selectedObiekt = request.getParameter("idObiekt");
int counter=0;
for (Obiekt obiekt : list) {
if(selectedObiekt == null && counter==0)
{
selectedObiekt = Integer.toString(obiekt.idObiekt);
}
%>
<option value="<%=obiekt.idObiekt%>"
<%= ((Integer.toString(obiekt.idObiekt)).equals(selectedObiekt))?"selected":""%>><%=obiekt.nazwa%>
<%=obiekt.adres%></option>
<%
}
%>
</select>
</form>
</div>
<div class="tabelawybor">
<td><b>Wpisz liczbę uczestników:</b><input type="text"
name="uczest" /></td>
<% String liczbaUczestnikow = request.getParameter("liczbaUczestnikow"); %>
</div>
<div class="tabelawybor">
<form action="Rezerwacja?action=doPost" method="post">
<table class="center">
<tr>
<td>Nazwa obiektu:</td>
<td>Data:</td>
<td>Godzina</br> rozpoczęcia:
</td>
<td>Godzina</br> zakończenia:
</td>
<td></td>
</tr>
<%
ListaTerminow listaterminow = new ListaTerminow();
listaterminow.setId(selectedObiekt);
ArrayList<Termin> lista =listaterminow.getTerminy();
String idTermin = request.getParameter("idTermin");
for (Termin termin : lista) {
%>
<tr>
<td><%=termin.nazwaObiektu%> <%=termin.adresObiektu%></td>
<td><%=termin.dzien%></td>
<td><%=termin.odKtorej%></td>
<td><%=termin.doKtorej%></td>
<td>
<button class="btn btn-primary">Zarezerwuj</button>
</td>
</tr>
<%
}
%>
</table>
</form>
</div>
</div>
</body>
</html>
In this jsp page i have select form which have List of Obiekt (this list is created in ListaObiektow.java), but it works. I also have table form which contains List of Termin (created in ListaTerminow.java). It works too. But, in this table form there is button to make Rezerwacja.
I made Rezerwuj servlet. Here is code:
package test;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import test.ConnectionClass;
import test.Rezerwacja;
import test.Termin;/**
* Servlet implementation class Rezerwuj
*/
#WebServlet("/Rezerwacja")
public class Rezerwuj extends HttpServlet {
private static final long serialVersionUID = 1L;
Connection conn;
private int idTermin;
private int liczbaUczestnikow;
public Rezerwuj() {
super();
}
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
conn = ConnectionClass.Polacz();
ArrayList<Rezerwacja> rezerwacje = new ArrayList<Rezerwacja>();
PreparedStatement st = null;
ResultSet rs = null;
String sql = "INSERT INTO rezerwacje (liczbaUczestnikow,idTermin) values ('" + liczbaUczestnikow + "','" + idTermin + "')"
+ "UPDATE termin SET termin.czyZajety=true WHERE termin.idTermin = '"+ idTermin +"'";
try
{
st = conn.prepareStatement(sql);
if(liczbaUczestnikow > 0 && liczbaUczestnikow < 20)
{
rs = st.executeQuery();
}
while(rs.next())
{
Rezerwacja rezerwacja = new Rezerwacja();
rezerwacja.setLiczbaUczestnikow(rs.getInt(1));
rezerwacja.setIdTermin(rs.getInt(2));
rezerwacje.add(rezerwacja);
}
}
catch(SQLException e)
{
System.out.println(e);
}
}
public void setIdTermin(String id)
{
idTermin = Integer.parseInt(id);
}
public void setliczbaUczestnikow(String liczba)
{
liczbaUczestnikow = Integer.parseInt(liczba);
}
}
When i click on the button, it returns error like this:
type Exception report
message
description The server encountered an internal error that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
test.Rezerwuj.doPost(Rezerwuj.java:63)
javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
What i want:
I select one of option in select form, then type value (0-20) into text input, then click on button and create a record in MySQL table Rezerwacja. Any suggestions ?
<form action="Rezerwacja?action=doPost" method="post">
In this line the action is where you are sending the request, so it should be action="Rezerwacja" and method should be method="POST"
I think you have problem with liczbaUczestnikow after initialization is always 0. As result rs always null, therefore exception thrown.

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