JDBC Simple Program

There are following six steps involved in building a JDBC application −

  1. Import the packages − Requires that you include the packages containing the JDBC classes needed for database programming. i.e import java.sql.*
  2. Open a connection − Requires using the DriverManager.getConnection() method to create a Connection object, which represents a physical connection with the database.
  3. Execute a query − Requires using an object of type Statement for building and submitting an SQL statement to the database.
  4. Extract data from result set − Requires that you use the appropriate ResultSet.getXXX() method to retrieve the data from the result set.
  5. Close All Connections − Requires explicitly closing all database resources versus relying on the JVM's garbage collection.
Sample JDBC Program

                        import java.sql.*;

                        public class SimpleJDBCProgramExample {
                        static final String DB_URL = "jdbc:mysql://localhost/testdb";
                        static final String USER = "guest";
                        static final String PASS = "guest123";
                        static final String QUERY = "SELECT id, first, last, age FROM Employees";

                            public static void main(String[] args) {
                                Connection conn = null;
                                Statement stmt = null;
                                ResultSet rs = null;
                                try {
                                    conn = DriverManager.getConnection(DB_URL, USER, PASS);
                                    stmt = conn.createStatement();
                                    rs = stmt.executeQuery(QUERY);
                                
                                    while (rs.next()) {
                                        System.out.print("ID: " + rs.getInt("id"));
                                        System.out.print(", Age: " + rs.getInt("age"));
                                        System.out.print(", First: " + rs.getString("first"));
                                        System.out.println(", Last: " + rs.getString("last"));
                                    }
                                } catch (SQLException e) {
                                    e.printStackTrace();
                                }
                                try {
                                    conn.close();
                                    stmt.close();
                                    rs.close(); 
                                } catch (Exception e) {
                                    e.printStackTrace();
                                }
                            }
                        }