JAVA DATABASE PROGRAMMING - Introduction to Java Programming: Comprehensive Version - page 1193

System.out.println(resultSet.getString( 1 ) + " " +
resultSet.getString( 2 ) + " " + resultSet.getString( 3 ));

The getString(1) , getString(2) , and getString(3) methods retrieve the col-
umn values for firstName , mi , and lastName , respectively. Alternatively, you can use
getString("firstName") , getString("mi") , and getString("lastName") to
retrieve the same three column values. The first execution of the next() method sets the cur-
rent row to the first row in the result set, and subsequent invocations of the next() method
set the current row to the second row, third row, and so on, to the last row.
Listing 32.1 is a complete example that demonstrates connecting to a database, executing
a simple query, and processing the query result with JDBC. The program connects to a local
MySQL database and displays the students whose last name is Smith .

L ISTING 32.1

SimpleJDBC.java
1 import java.sql.*;
2
3 public class SimpleJdbc {
4 public static void main(String[] args)
5 throws SQLException, ClassNotFoundException {
6 // Load the JDBC driver
7 Class.forName( "com.mysql.jdbc.Driver" );
8 System.out.println( "Driver loaded" );
9
10 // Connect to a database
11 Connection connection = DriverManager.getConnection
12 ( "jdbc:mysql://localhost/javabook" , "scott" , "tiger" );
13 System.out.println( "Database connected" );
14
15

load driver

connect database

// Create a statement

16 Statement statement = connection.createStatement();

create statement

17
18 // Execute a statement

19 ResultSet resultSet = statement.executeQuery

execute statement

20 ( "select firstName, mi, lastName from Student where lastName "

21 + " = 'Smith'" );

22
23 // Iterate through the result and print the student names
24 while (resultSet.next())
25 System.out.println(resultSet.getString( 1 ) + "\t" +
26

get result

resultSet.getString( 2 ) + "\t" + resultSet.getString( 3 ));

27
28

// Close the connection

29 connection.close();

close connection

30 }
31 }

The statement in line 7 loads a JDBC driver for MySQL, and the statement in lines 11-13
connects to a local MySQL database. You can change them to connect to an Access or Oracle
database. The program creates a Statement object (line 16), executes an SQL statement and
returns a ResultSet object (lines 19-21), and retrieves the query result from the ResultSet
object (lines 24-26). The last statement (line 29) closes the connection and releases resources
related to the connection. You can rewrite this program using the try-with-resources syntax.
See www.cs.armstrong.edu/liang/intro10e/html/SimpleJdbcWithAutoClose.html .

Note
If you run this program from the DOS prompt, specify the appropriate driver in the
classpath, as shown in Figure 32.22.

run from DOS prompt