Sample JDBC Database Connection

DBOperations.java

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package testui;

//Import required packages
import java.sql.*;

/**
 *
 * @author sathindu
 */
public class DBOperations {

    //JDBC driver name and database URL
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost:3306/database_name";

    //Database credentials
    static final String USER = "root";
    static final String PASS = "password";

    void addEmployee(int id, String name, String email) {
        
        Connection con = null;
        PreparedStatement pst = null;

        try {
            //Register JDBC driver
            Class.forName(JDBC_DRIVER);

            //Open a connection
            System.out.println("Connecting to Database...");
            con = DriverManager.getConnection(DB_URL, USER, PASS);

            //Creating PreparedStatement
            System.out.println("Creating PreparedStatement");
            String query = "INSERT INTO employee VALUES (?,?,?)";
            pst = (PreparedStatement) con.prepareStatement(query);

            pst.setInt(1, id);
            pst.setString(2, name);
            pst.setString(3, email);

            //Execute the PreparedStatement
            System.out.println("Start Executing PreparedStatement...");
            int res = pst.executeUpdate();
            System.out.println(res + " Rows Affected...");

        } catch (SQLException ex) {
            //Handle errors for JDBC
            ex.printStackTrace();
        } catch (Exception ex) {
            //Handle other errors
            ex.printStackTrace();
        } finally {
            //Finally block used to close resources
            try {
                if (pst != null) {
                    pst.close();
                    System.out.println("PreparedStatement Closed...");
                }
            } catch (SQLException se2) {

            }
            try {
                if (con != null) {
                    con.close();
                    System.out.println("Database Connetion Closed...");
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
        System.out.println("Completed...");
    }

    void printEmployees() {

        Connection con = null;
        Statement sta = null;

        try {
            //Register JDBC driver
            Class.forName(JDBC_DRIVER);

            //Open a connection
            System.out.println("Connecting to Database...");
            con = DriverManager.getConnection(DB_URL, USER, PASS);

            //Execute a query
            System.out.println("Creating Statement...");
            sta = con.createStatement();
            String sql = "SELECT id, name, email FROM employee";
            System.out.println("Executing Statement...");
            ResultSet rs = sta.executeQuery(sql);

            // Extract data from result set
            while (rs.next()) {
                //Retrieve by column name
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String email = rs.getString("email");

                //Display values
                System.out.print("ID: " + id);
                System.out.print(", Name: " + name);
                System.out.println(", Email: " + email);
            }

            //Cleaning up environment
            rs.close();

        } catch (SQLException ex) {
            //Handle errors for JDBC
            ex.printStackTrace();
        } catch (Exception ex) {
            //Handle other errors
            ex.printStackTrace();
        } finally {
            //Finally block used to close resources
            try {
                if (sta != null) {
                    sta.close();
                    System.out.println("Statement Closed...");
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }

            try {
                if (con != null) {
                    con.close();
                    System.out.println("Database Connection Closed...");
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
        System.out.println("Completed...");
    }

}