A Simple Database Query Program
Listing 3.1 shows a simple JDBC query program. The database used for this example is the Cloudscape database, a 100% pure Java database available from http://www.cloudscape.com. The program puts together the various concepts you have already seen in this chapter.
Listing 3.1 Source Code for SimplyQuery.java
package usingj2ee.jdbc;
import java.sql.*;
public class SimpleQuery
{
public static void main(String[ ] args)
{
try
{
// Make sure the DriverManager knows about the driver
Class.forName("COM.cloudscape.core.JDBCDriver");
// Create a connection to the database
Connection conn = DriverManager.getConnection(
"jdbc:cloudscape:j2eebook");
// Create a statement
Statement stmt = conn.createStatement();
// Execute the query
ResultSet results = stmt.executeQuery(
"select * from person");
// Loop through all the results
while (results.next())
{
// Get the values from the result set
String firstName = results.getString("first_name");
String middleName = results.getString("middle_name");
String lastName = results.getString("last_name");
int age = results.getInt("age");
// Print out the values
System.out.println(firstName+" "+middleName+" "+lastName+
" "+age);
}
conn.close();
}
catch (Exception exc)
{
exc.printStackTrace();
}
}
}
TIP
Don't forget to include the JDBC driver in your classpath before running the example. If you are using a database other than Cloudscape, you must also change both the driver name and the database URL.