JDBC - Select Database Example

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This chapter provides an example on how to select a Database using JDBC application. Before executing the following example, make sure you have the following in place −

  • To execute the following example you need to replace the username and password with your actual user name and password.

  • Your MySQL or whatever database you are using, is up and running.

Required Steps

The following steps are required to create a new Database using JDBC application −

  • Import the packages: Requires that you include the packages containing the JDBC classes needed for the database programming. Most often, using import java.sql.* will suffice.

  • Register the JDBC driver: Requires that you initialize a driver so you can open a communications channel with the database.

  • Open a connection: Requires using the DriverManager.getConnection() method to create a Connection object, which represents a physical connection with a selected database.

    Selection of database is made while you prepare database URL. Following example would make connection with STUDENTS database.

  • Clean up the environment: Requires explicitly closing all the database resources versus relying on the JVM's garbage collection.

Sample Code

Copy and past the following example in JDBCExample.java, compile and run as follows −

//STEP 1. Import required packages
import java.sql.*;

public class JDBCExample {
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
   static final String DB_URL = "jdbc:mysql://localhost/STUDENTS";

   //  Database credentials
   static final String USER = "username";
   static final String PASS = "password";
   
   public static void main(String[] args) {
   Connection conn = null;
   try{
      //STEP 2: Register JDBC driver
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: Open a connection
      System.out.println("Connecting to a selected database...");
      conn = DriverManager.getConnection(DB_URL, USER, PASS);
      System.out.println("Connected database successfully...");
   }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(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try
   System.out.println("Goodbye!");
}//end main
}//end JDBCExample

Now, let us compile the above example as follows −

C:\>javac JDBCExample.java
C:\>

When you run JDBCExample, it produces the following result −

C:\>java JDBCExample
Connecting to a selected database...
Connected database successfully...
Goodbye!
C:\>
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