Sample Code:

This sample example can serve as a template when you need to create your own JDBC application in the future.
This sample code has been written based on the environment and database setup done in previous chapter.
Copy and past following example in FirstExample.java, compile and run as follows:



//STEP 1. Import required packages

import java.sql.*;


public class FirstExample {

   // JDBC driver name and database URL

   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  

   static final String DB_URL = "jdbc:mysql://localhost/EMP";


   //  Database credentials

   static final String USER = "username";

   static final String PASS = "password";

   
   public static void main(String[] args) {

   Connection conn = null;

   Statement stmt = null;

   try{
      //STEP 2: Register JDBC driver

      Class.forName("com.mysql.jdbc.Driver");


      //STEP 3: Open a connection

      System.out.println("Connecting to database...");

      conn = DriverManager.getConnection(DB_URL,USER,PASS);


      //STEP 4: Execute a query

      System.out.println("Creating statement...");

      stmt = conn.createStatement();

      String sql;
      sql = "SELECT id, first, last, age FROM Employees";

      ResultSet rs = stmt.executeQuery(sql);


      //STEP 5: Extract data from result set

      while(rs.next()){

         //Retrieve by column name

         int id  = rs.getInt("id");

         int age = rs.getInt("age");

         String first = rs.getString("first");

         String last = rs.getString("last");


         //Display values

         System.out.print("ID: " + id);

         System.out.print(", Age: " + age);

         System.out.print(", First: " + first);

         System.out.println(", Last: " + last);

      }
      //STEP 6: Clean-up environment

      rs.close();

      stmt.close();

      conn.close();

   }catch(SQLException se){

      //Handle errors for JDBC

      se.printStackTrace();

   }catch(Exception e){

      //Handle errors for Class.forName

      e.printStackTrace();

   }finally{

      //finally block used to close resources

      try{

         if(stmt!=null)

            stmt.close();

      }catch(SQLException se2){

      }// nothing we can do

      try{

         if(conn!=null)

            conn.close();

      }catch(SQLException se){

         se.printStackTrace();

      }//end finally try

   }//end try

   System.out.println("Goodbye!");

}//end main

}//end FirstExample