//source file: util/DB.java
package util;
import java.sql.Connection;
import java.sql.DriverManager;
public class DB {
private static DB instance;
private static final int MAX_CON = 5;
private static final Connection[] bafer = new Connection[MAX_CON];
private int first = 0, last = 0, free = MAX_CON;
private DB() { //za MySQL
try {
Class.forName("com.mysql.jdbc.Driver");
for (int i = 0; i < MAX_CON; i++) {
bafer[i] =
DriverManager.getConnection
("jdbc:mysql://localhost:3306/dbkorisnik", "root", "");
}
} catch (Exception e) {
e.printStackTrace();
}
}
/* za Access
private DB(){
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
for(int i=0; i<MAX_CON; i++)
bafer[i] = DriverManager.getConnection("jdbc:odbc:dbkorisnik");
}catch(Exception e){}
}
*/
public static DB getInstance() {
if (instance == null) {
instance = new DB();
}
return instance;
}
public synchronized Connection getConnection() {
if (free == 0) {
return null;
}
free--;
Connection con = bafer[first];
first = (first + 1) % MAX_CON;
return con;
}
public synchronized void putConnection(Connection con) {
if (con == null) {
return;
}
free++;
bafer[last] = con;
last = (last + 1) % MAX_CON;
}
}

//source file: beans/Korisnik.java
//Java bean
package beans;
public class Korisnik {
private String username = "";
private String password = "";
private String email = "";
private String telefon = "";
private String ime = "";
private String prezime = "";
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;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getTelefon() {
return telefon;
}
public void setTelefon(String telefon) {
this.telefon = telefon;
}
public String getIme() {
return ime;
}
public void setIme(String ime) {
this.ime = ime;
}
public String getPrezime() {
return prezime;
}
public void setPrezime(String prezime) {
this.prezime = prezime;
}
}
//source file: servleti/Login.java
//servlet za logovanje korisnika u sistem
package servleti;
import beans.*;
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import util.DB;
public class Login extends HttpServlet {
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
HttpSession sesija = request.getSession();
String poruka = "";
String username = (String) request.getParameter("username");
String password = (String) request.getParameter("password");
Korisnik korisnik = new Korisnik();
korisnik.setUsername(username);
korisnik.setPassword(password);
sesija.setAttribute("korisnik", korisnik);
if (username.isEmpty() || password.isEmpty()) {
poruka = "Niste popunili sva polja!";
request.setAttribute("poruka", poruka);
RequestDispatcher rd = request.getRequestDispatcher("/index.jsp");
rd.forward(request, response);
}
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
String address = "prikaz.jsp";
try {
con = DB.getInstance().getConnection();
stmt = con.createStatement();
String upit = "select * from KorisnikInfo where username='" +
username + "' and password='" + password + "';";
rs = stmt.executeQuery(upit);
if (rs.next()) {
String email = rs.getString("email");
String ime = rs.getString("first_name");
String prezime = rs.getString("last_name");
String telefon = rs.getString("phone");
korisnik.setEmail(email);
korisnik.setIme(ime);
korisnik.setPrezime(prezime);
korisnik.setTelefon(telefon);
stmt.close();
request.setAttribute("poruka", "Vasi podaci");
} else {
poruka = "Neispravno korisnicko ime i lozinka!
Pokusajte ponovo.";
request.setAttribute("poruka", poruka);
korisnik.setPassword("");
address = "index.jsp";
stmt.close();
}
} catch (SQLException ex) {
sesija.invalidate();
String errormsg = ex.getMessage();
request.setAttribute("errormsg", errormsg);
address = "error.jsp";
} finally {
DB.getInstance().putConnection(con);
}
RequestDispatcher rd = request.getRequestDispatcher(address);
rd.forward(request, response);
}
}
//source file: servleti/Logout.java
//servlet za izlogovanje korisnika iz sistema
package servleti;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Logout extends HttpServlet {
protected void processRequest(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
request.getSession().invalidate();
request.getRequestDispatcher("kraj.jsp").forward(request, response);
}
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}
//source file: servleti/Izmena.java
//servlet za promenu podataka o korisniku
package servleti;
import beans.Korisnik;
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import util.DB;
public class Izmena extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
HttpSession sesija = request.getSession();
Korisnik korisnik = (Korisnik) sesija.getAttribute("korisnik");
String ime = (String) request.getParameter("ime");
String prezime = (String) request.getParameter("prezime");
String telefon = (String) request.getParameter("telefon");
String email = (String) request.getParameter("email");
korisnik.setIme(ime);
korisnik.setPrezime(prezime);
korisnik.setTelefon(telefon);
korisnik.setEmail(email);
String upit = "update KorisnikInfo "
+ "set first_name='" + ime + "',last_name='" + prezime
+ "', phone='" + telefon + "', email='" + email + "'"
+ "where username='" + korisnik.getUsername() + "';";
Connection con = null;
Statement stmt = null;
String address = "prikaz.jsp";
try {
con = DB.getInstance().getConnection();
stmt = con.createStatement();
stmt.executeUpdate(upit);
stmt.close();
con.close();
} catch (SQLException ex) {
sesija.invalidate();
String errormsg = ex.getMessage();
request.setAttribute("errormsg", errormsg);
address = "error";
} finally {
DB.getInstance().putConnection(con);
}
request.setAttribute("poruka", "Podaci su uspesno izmenjeni");
RequestDispatcher rd = request.getRequestDispatcher(address);
rd.forward(request, response);
}
}
//web page: index.jsp
//prva strana za logovanje korisnika
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Korisnička aplikacija</title>
</head>
<body>
<h3>${(poruka!=null) ? poruka : "Dobrodošli!"} </h3><br/><br/>
<form action="login" method="POST">
<table>
<tr>
<td>Korisničko ime:</td>
<td><input type="text" name="username"
value="${korisnik.username}" size="20"/></td>
</tr>

<tr>
<td>Lozinka:</td>
<td><input type="password" name="password"
value="${korisnik.password}" size="20"/></td>
</tr>
<tr>
<td><input type="submit" value="Ulogujte se"/></td>
<td><input type="reset" value="Poništite"/></td>
</tr>
</table>
</form>
</body>
</html>
//web page: kraj.jsp
//poslednja strana kada se korisnik izloguje
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Doviđenja</title>
</head>
<body>
<h1>Doviđenja</h1>
<a href="index.jsp">Na početak</a>
</body>
</html>

//web page: prikaz.jsp
//prva strana nakon logovanja, koja prikazuje podatke o korisniku
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html>
<head>
<title>Korisnička aplikacija</title>
</head>
<body>
<h3>${poruka}</h3><br/><br/>
<table width="40%" border="3">
<tr><td width="50%"> Korisničko ime:</td>
<td>${korisnik.username} </td></tr>
<tr><td>Ime:</td>
<td>${korisnik.ime}</td></tr>
<tr><td>Prezime:</td>
<td>${korisnik.prezime}</td></tr>
<tr><td>Email:</td>
<td>${korisnik.email}</td></tr>
<tr><td>Telefon:</td>
<td>${korisnik.telefon}</td></tr>
</table><br/>
<a href="promena.jsp">Promenite podatke</a>
<a href="logout">Izlogujte se</a>
</body>
</html>
//web page: promena.jsp
//strana na kojoj korisnik moze promeniti svoje podatke
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html>
<head>
<title>Korisnička aplikacija</title>
</head>
<body>
<h3>Vaši podaci koje možete menjati</h3><br/><br/>
<form action="izmena" method="post" >
<table width="40%" border="3">
<tr><td width="50%">Ime:</td>
<td><input type="text" name="ime" value="${korisnik.ime}"
size="30"/></td></tr>
<tr><td>Prezime:</td>
<td><input type="text" name="prezime"
value="${korisnik.prezime}" size="30"/></td></tr>
<tr><td>Email:</td>
<td><input type="text" name="email" value="${korisnik.email}"
size="30"/></td></tr>
<tr><td>Telefon:</td>
<td><input type="text" name="telefon"
value="${korisnik.telefon}" size="30" /></td></tr>
</table><br/>
<input type="submit" value="Prihvatite izmenu"/>
</form>
</body>
</html>

//web page: error.jsp
//strana na kojoj se prikazuje poruka o gresci
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Greška</title>
</head>
<body>
<h1>Greška u radu sa bazom podataka</h1>
<h3>${errormsg}</h3>
</body>
</html>