Connecting to database in Java with JDBC.

ConnectJDBC3.java

/**
 * Connecting to database in Java with JDBC 3.0 and backward.
 *
 * @author: Mohamed Riyad <@RyadPasha>
 * @url: http://ryadpasha.com
 * @email: me@ryadpasha.com
 * @license: MIT License
 */
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
 
public class ConnectJDBC3 {
    public static void main(String[] args) {
        String databaseURL = "jdbc:mysql://localhost:3306/test";
        String user = "user";
        String password = "password";
        Connection conn = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(databaseURL, user, password);
            if (conn != null) {
                System.out.println("Connected to the database");
            }
        } catch (ClassNotFoundException ex) {
            System.out.println("Could not find database driver class");
            ex.printStackTrace();
        } catch (SQLException ex) {
            System.out.println("An error occurred. Maybe user/password is invalid");
            ex.printStackTrace();
        } finally {
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
        }
    }
}

ConnectJDBC4.java

/**
 * Connecting to database in Java with JDBC 4.0 and later.
 * Example 1: getConnection(String url)
 * In this way, we must pass the user and password directly into the database URL.
 *
 * @author: Mohamed Riyad <@RyadPasha>
 * @url: http://ryadpasha.com
 * @email: me@ryadpasha.com
 * @license: MIT License
 */
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
 
public class DBConnect1 {
    public static void main(String[] args) {
        String databaseURL = "jdbc:mysql://localhost:3306/test?user=root&password=root123";
        Connection conn = null;
        try {
            conn = DriverManager.getConnection(databaseURL);
            if (conn != null) {
                System.out.println("Connected to the database");
            }
        } catch (SQLException ex) {
            System.out.println("An error occurred. Maybe user/password is invalid");
            ex.printStackTrace();
        } finally {
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
        }
    }
}

ConnectJDBC4_ex2.java

/**
 * Connecting to database in Java with JDBC 4.0 and later.
 * Example 2: getConnection(String url, Properties info)
 * In this way, we put the user and password in a Properties object.
 *
 * @author: Mohamed Riyad <@RyadPasha>
 * @url: http://ryadpasha.com
 * @email: me@ryadpasha.com
 * @license: MIT License
 */
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
 
public class DBConnect2 {
    public static void main(String[] args) {
        String databaseURL = "jdbc:mysql://localhost:3306/test";
        Connection conn = null;
        try {
            Properties props = new Properties();
            props.put("user", "root");
            props.put("password", "root123");
            conn = DriverManager.getConnection(databaseURL, props);
            if (conn != null) {
                System.out.println("Connected to the database");
            }
        } catch (SQLException ex) {
            System.out.println("An error occurred. Maybe user/password is invalid");
            ex.printStackTrace();
        } finally {
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
        }
    }
}

ConnectJDBC4_ex3.java

/**
 * Connecting to database in Java with JDBC 4.0 and later.
 * Example 3: getConnection(String url, String user, String password)
 * In this way, we supply the user and password directly into the method’s arguments.
 *
 * @author: Mohamed Riyad <@RyadPasha>
 * @url: http://ryadpasha.com
 * @email: me@ryadpasha.com
 * @license: MIT License
 */
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
 
public class DBConnect3 {
    public static void main(String[] args) {
        String databaseURL = "jdbc:mysql://localhost:3306/test";
        String user = "root";
        String password = "root123";
        Connection conn = null;
        try {
            conn = DriverManager.getConnection(databaseURL, user, password);
            if (conn != null) {
                System.out.println("Connected to the database");
            }
        } catch (SQLException ex) {
            System.out.println("An error occurred. Maybe user/password is invalid");
            ex.printStackTrace();
        } finally {
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
        }
    }
}