发信人: ago()
整理人: hht(1999-03-11 11:47:11), 站内信件
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import java.applet.Applet;
import java.awt.Graphics;
import java.util.Vector;
import java.sql.*;
public class test 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();
}
}
public void run() {
String url = "jdbc:sybase:Tds:202.97.228.248:4100/pubs3";
String query = "select a from test";
try {
Class.forName("com.sybase.jdbc.SybDriver");
} catch(Exception ex) {
setError("Can't find Database driver class: " + ex);
return;
}
try {
Vector results = new Vector();
Connection con = DriverManager.getConnection(url,"sa", "great1");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(query);
while (rs.next())
{
String s = rs.getString("a");
//float f = rs.getFloat("PRICE");
String text = s;// + " " + f;
results.addElement(text);
}
stmt.close();
con.close();
setResults(results);
} catch(SQLException ex)
{
setError("SQLException: " + ex);
}
}
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;
}
}
private synchronized void setError(String mess)
{
queryResults = null;
message = mess;
worker = null;
// And ask AWT to repaint this applet.
repaint();
}
private synchronized void setResults(Vector results)
{
queryResults = results;
worker = null;
// And ask AWT to repaint this applet.
repaint();
}
}
--
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ago
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