<resource-ref>
        <res-ref-name>jdbc/Library</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
        <res-sharing-scope>Shareable</res-sharing-scope>
    </resource-ref>

package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

public class TestJDBC {
    
    public void check() throws NamingException{
       
        try {
            InitialContext ic = new InitialContext();
            DataSource ds = (DataSource) ic.lookup("java:comp/env/jdbc/Library");
            Connection conn = ds.getConnection();
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("select * from book");
            
            while (rs.next()) {
                System.out.println(rs.getString("name"));                
            }
            
        } catch (SQLException ex) {
            Logger.getLogger(TestJDBC.class.getName()).log(Level.SEVERE, null, ex);
        }
        
        catch (NamingException ex) {
            Logger.getLogger(TestJDBC.class.getName()).log(Level.SEVERE, null, ex);
        }
        
    }
}