JDBC + WEB

/**
 * This is a demonstration JDBC applet.
 * It displays some simple standard output from the Coffee database.
 */

import java.applet.Applet;
import java.awt.Graphics;
import java.util.Vector;
import java.sql.*;

public class OutputApplet extends Applet implements Runnable {
    private Thread worker;
    private Vector queryResults;
    private String message = "Initializing";

    public synchronized void start() {
    // Every time "start" is called we create a worker thread to
    // re-evaluate the database query.
    if (worker == null) {  
        message = "Connecting to database";
            worker = new Thread(this);
        worker.start();
    }
    }

    /**
     * The "run" method is called from the worker thread.  Notice that
     * because this method is doing potentially slow databases accesses
     * we avoid making it a synchronized method.
     */

    public void run() {
    String url = "jdbc:mySubprotocol:myDataSource";
    String query = "select COF_NAME, PRICE from COFFEES";
   
    try {
        Class.forName("myDriver.ClassName");
    } catch(Exception ex) {
        setError("Can't find Database driver class: " + ex);
        return;
    }

    try {
        Vector results = new Vector();
        Connection con = DriverManager.getConnection(url,
                        "myLogin", "myPassword");
        Statement stmt = con.createStatement();
        ResultSet rs = stmt.executeQuery(query);
        while (rs.next()) {
        String s = rs.getString("COF_NAME");
        float f = rs.getFloat("PRICE");
        String text = s + "     " + f;
        results.addElement(text);
        }

        stmt.close();
        con.close();

        setResults(results);

    } catch(SQLException ex) {
        setError("SQLException: " + ex);
    }
    }

    /**
     * The "paint" method is called by AWT when it wants us to
     * display our current state on the screen.
     */

    public synchronized void paint(Graphics g) {
    // If there are no results available, display the current message.
    if (queryResults == null) {
        g.drawString(message, 5, 50);
        return;
    }

    // Display the results.
    g.drawString("Prices of coffee per pound:  ", 5, 10);
    int y = 30;
    java.util.Enumeration enum = queryResults.elements();
    while (enum.hasMoreElements()) {
        String text = (String)enum.nextElement();
        g.drawString(text, 5, y);
        y = y + 15;
    }
    }

    /**
     * This private method is used to record an error message for
     * later display.
     */

    private synchronized void setError(String mess) {
    queryResults = null;   
    message = mess;
    worker = null;
    // And ask AWT to repaint this applet.
    repaint();
    }

    /**
     * This private method is used to record the results of a query, for
     * later display.
     */

    private synchronized void setResults(Vector results) {
    queryResults = results;
    worker = null;
    // And ask AWT to repaint this applet.
    repaint();
    }
}

import java.sql.*;

public class CreateCoffees {
    public static void main(String args[]) {
        String url = "jdbc:mySubprotocol:myDataSource";
        Connection con;
        String createString;
        createString = "create table COFFEES " +
                            "(COF_NAME VARCHAR(32), " +
                            "SUP_ID INTEGER, " +
                            "PRICE FLOAT, " +
                            "SALES INTEGER, " +
                            "TOTAL INTEGER)";
        Statement stmt;

        try {
            Class.forName("myDriver.ClassName");
        } catch(java.lang.ClassNotFoundException e) {
            System.err.print("ClassNotFoundException: ");
            System.err.println(e.getMessage());
        }

        try {
            con = DriverManager.getConnection(url, "myLogin", "myPassword");
            stmt = con.createStatement();
            stmt.executeUpdate(createString);
            stmt.close();
            con.close();

        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
        }
    }
}

<HTML>
<HEAD>
<TITLE> Query Output </TITLE>
</HEAD>
<BODY>

Output from query
select NAME, PRICE from COFFEES
<APPLET CODE="OutputApplet.class" WIDTH=250 HEIGHT=200>
</APPLET>
</BODY>
</HTML>