Using Hibernate to connect to a database from a Java application

Objective
We will learn how to use hibernate to connect to a database in a concrete application of Login.

Architect of a hibernate application
A hibernate application could have five main components as follows:
- DB tables: a database in any DBMS, in this example that is hotelmanagement in MySQL
- mapping config files: these xml file will config how a tables from DB could be mapped into a POJO class
- POJO (Plain Old Java Object) classes: once being mapped from a BD, these classes will play the role as that of corresponding table.
- Hibernate config file: this xml file will config how to connect to the database, and point out where the mapping config files are stored.
- DAO/control classes: the business layer of application
- View classes: the GUI layer of application



Now let start to develop an application of login using this architect.

 - Step 1: create a Java project in Eclipse with these packages and classes:



- Step 2: add hibernate library file (download from http://www.hibernate.org/downloads) into JRE system library of the project:




- Step 3: create a database named "hotelmanagement" in MySQL, in which create a table named "tblUser" with these columns:




- Step 4: Edit the file Hibernate.cfg.xml as:

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
  <session-factory>
    <property name="connection.driver_class"> com.mysql.jdbc.Driver </property>
    <property name="connection.url">jdbc:mysql://localhost:3306/hotelmanagement  </property>
    <property name="connection.username">root</property>
    <property name="connection.password">12345678</property>
    <property name="connection.pool_size">1</property>
    <property name="dialect">org.hibernate.dialect.MySQLDialect </property>
    <property name="current_session_context_class">thread</property>
    <property name="cache.provider_class"> org.hibernate.cache.NoCacheProvider
        </property>
    <property name="show_sql">true</property>
    <property name="hbm2ddl.auto">update</property>

    <mapping resource="user.hbm.xml"/>
  </session-factory>
</hibernate-configuration>

Note that the red marked parts are the content you need to edit base on your configuration.


- Step 5: create POJO class of User:

package model;
import java.io.Serializable;

public class User implements Serializable{
    private static final long serialVersionUID = 1L;
    private Integer id;
    private String username;
    private String password;
    private String fullName;
    private String idCardNumber;
    private String idCardType;
    private String address;
    private String description;
   
    public User(){
       
    }
       
    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }
   
    public String getFullName() {
        return fullName;
    }

    public void setFullName(String fullName) {
        this.fullName = fullName;
    }

    public String getIdCardNumber() {
        return idCardNumber;
    }

    public void setIdCardNumber(String idCardNumber) {
        this.idCardNumber = idCardNumber;
    }

    public String getIdCardType() {
        return idCardType;
    }


    public void setIdCardType(String idCardType) {
        this.idCardType = idCardType;
    }

    public String getAddress() {
        return address;
    }


    public void setAddress(String address) {
        this.address = address;
    }

    public String getDescription() {
        return description;
    }


    public void setDescription(String description) {
        this.description = description;
    }

    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;
    }  
}


- Step 6: Config the User.hbm.xml file

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
 <class name="model.User" table="tbluser" >
  <id name="id" type="int" column="id" >
   <generator class="native"/>
  </id>

  <property name="username">
   <column name="username" />
  </property>
  <property name="password">
   <column name="password"/>
  </property>
  <property name="fullName">
   <column name="fullName" />
  </property>
  <property name="idCardNumber">
   <column name="idCardNumber"/>
  </property>
  <property name="idCardType">
   <column name="idCardType" />
  </property>
  <property name="address">
   <column name="address"/>
  </property>
  <property name="description">
   <column name="description" />
  </property>
 </class>
</hibernate-mapping>

- Step 7: HibernateUser class
package control;
import java.util.List;
import model.User;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

public class HibernateUser {
    private static final SessionFactory sessionFactory = buildSessionFactory();
   
    private static SessionFactory buildSessionFactory() {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            return new AnnotationConfiguration().configure().buildSessionFactory();
        } catch (Throwable ex) {
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
   
    public boolean checkLogin(User user){
        boolean result = false;
        Session session = this.getSessionFactory().getCurrentSession();
        session.beginTransaction();
        List<User> users = null;
        String sql = "FROM User U WHERE U.username = :username AND U.password = :password";
        try {
            Query q =  session.createQuery(sql);
            q.setParameter("username", user.getUsername());
            q.setParameter("password", user.getPassword());
            users = (List<User>)q.list();
            if (users.size() > 0) result = true;
            
        } catch (HibernateException e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }
        session.getTransaction().commit();
        return result;
    }
}

- Step 8: LoginControl class

package control;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import model.User;
import view.LoginView;

public class LoginControl {
    private User model;
    private LoginView view;

    public LoginControl(LoginView view){
        this.view = view;   
        view.addLoginListener(new LoginListener());
    }

    class LoginListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            try {
                model = view.getUser();
                HibernateUser hu = new HibernateUser();
                if(hu.checkLogin(model)){
                    view.showMessage("Login succesfully!");
                }else{
                    view.showMessage("Invalid username and/or password!");
                }               
            } catch (Exception ex) {
                view.showMessage(ex.getStackTrace().toString());
            }
        }
    }
   
    public static void main(String[] args) {
        LoginView view       = new LoginView();
        LoginControl controller = new LoginControl(view);       
        view.setVisible(true);
    }
}

- Step 9: LoginView class

package view;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import model.User;

public class LoginView extends JFrame implements ActionListener{
    private JTextField txtUsername;
    private JPasswordField txtPassword;
    private JButton btnLogin;
    private User model;
   
    public LoginView(){
        super("Login MVC using Hibernate");
       
        txtUsername = new JTextField(15);
        txtPassword = new JPasswordField(15);
        txtPassword.setEchoChar('*');
        btnLogin = new JButton("Login");
       
        JPanel content = new JPanel();
        content.setLayout(new FlowLayout());
        content.add(new JLabel("Username:"));
        content.add(txtUsername);
        content.add(new JLabel("Password:"));
        content.add(txtPassword);
        content.add(btnLogin);
         
        btnLogin.addActionListener(this);
       
        this.setContentPane(content);
        this.pack();
       
        this.addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                System.exit(0);
            }
        });
    }

    public void actionPerformed(ActionEvent e) {
    }
   
    public User getUser(){
        model = new User();
        model.setUsername(txtUsername.getText());
        model.setPassword(txtPassword.getText());
        return model;       
    }
   
    public void showMessage(String msg){
        JOptionPane.showMessageDialog(this, msg);
    }
   
    public void addLoginListener(ActionListener log) {
          btnLogin.addActionListener(log);
        }
}

Results
 Login interface:



Login success interface:



Login failed interface: