Peter T Mount wrote:
> On Wed, 28 Oct 1998, Murad Nayal wrote:
>
> > > I am baffled:
> > >
> > > I wrote a small java program to test postgresql jdbc driver. the applet
> > > runs fine locally using applet viewer. indicating that the driver is
> > > recognizing the url and responding to it correctly. however I get the
> > > message "NO suitable Driver" when the applet is run from a remote
> > > browser. the Class.forName("postgresql.Driver"); does not produce an
> > > exception leading me to believe that the Driver is found but it is not
> > > accepting the url (same one that worked locally)?
>
> Ok, applets can be horrible little things, and sometimes it's not their
> fault. Nine times out of ten it's the sandbox (applet security), or a
> browser not handling java 1.1 or jdbc (some don't know about jdbc :-( )
>
> Your code looks ok. I placed your URL into an application here, and all I
> got was:
>
> Connection failed: java.net.UnknownHostException: godel.bioc.columbia.edu
>
> which is ok, as I wasn't connected at the time ;-)
>
> > > <Applet code="JDBCtest.class" archive=postgresql.jar width=300
> > > height=300> </Applet>
>
> As far as I can see, your problem is here.
>
> First, don't put .class in the code argument. It can break some browsers.
> Technically it's the class name that goes here, not the file name.
>
> The main problem is the archive argument. The browser is loading the
> postgresql.jar file, looking for the JDBCtest class. It fails, so it then
> looks at the directory that the html file is in. It find's JDBCtest, but
> as it's not in the jar file, some browsers implementations of the
> "Sandbox" prevents the driver to be found.
>
> There are two solutions:
>
> extract the files from postgresql.jar into your html directory
>
> or
>
> create a new jar file containing the contents of postgresql.jar
> and your applet.
>
> Remember: it's important to keep the directory structure.
Thank you for your suggestions. I followed your directions by unzipping the
jar file in the html directory, removed the archive attribute from the
<applet> tag and remove the class extension from the code attribute in the
applet tag. Now netscape produces: user authentication failed exception while
internet explorer produces No suitable driver exception. Mind you, the
connection works just fine if you do it using the appletviewer locally on the
machine. I am including next a copy of the html and the java files with just
the user password obsecured (you have to trust me it does work :-)).
thanks indeed for any suggestions and help
URL:
http://godel.bioc.columbia.edu/~secourse/JDBCtest.html
JDBCtest.html:
<html>
<head>
<title>Java Database Connectivity Test</title>
</head>
<body>
Enter one of the following company symbols:
SGI, CCI, CMB. A bit of a small database I know.
<Applet code="JDBCtest" width=300 height=300> </Applet>
</html>
JDBCtest.java
import java.sql.*;
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import java.util.*;
public class JDBCtest extends Applet implements ActionListener {
String url = "jdbc:postgresql://godel.bioc.columbia.edu:1212/stockprices";
String usr = "murad";
String pwd = "*******";
Connection con;
Statement stmt;
ResultSet res;
static final String DOIT = "GETPRICE";
TextField price;
TextField symbol;
TextField stat;
Label thesymbol;
Label theprice;
Button doit;
public void init() {
try {
Class.forName("postgresql.Driver");
System.out.println("After class loading");
con = DriverManager.getConnection(url, usr, pwd);
System.out.println("After connection");
stmt = con.createStatement();
} catch (Exception e) {
System.out.println("Just caught an exception");
System.out.println(e.getMessage());
e.printStackTrace();
}
price = new TextField(20);
price.setEditable(false);
stat = new TextField(20);
stat.setEditable(false);
symbol = new TextField(20);
thesymbol = new Label("Stock symbol");
theprice = new Label("Stock price");
doit = new Button("Get price");
doit.addActionListener(this);
doit.setActionCommand(DOIT);
setLayout(new GridLayout(3,2));
add(thesymbol);
add(symbol);
add(theprice);
add(price);
add(doit);
add(stat);
validate();
}
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if(command == DOIT) {
String query;
float stockprice=0;
String secsym = symbol.getText();
stat.setText("Contacting database. please wait");
try {
query = "Select price FROM stockinfo WHERE symbol = \'";
query += secsym + "\';";
res = stmt.executeQuery(query);
while(res.next()) {
stockprice = res.getFloat("price");
}
price.setText(String.valueOf(stockprice));
stat.setText("Updated price");
} catch (Exception ee) {
System.out.println("Just caught an exception");
System.out.println(ee.getMessage());
ee.printStackTrace();
}
}
}
public void destroy() {
try {
stmt.close();
con.close();
} catch (Exception ee) {
System.out.println("Just caught an exception");
System.out.println(ee.getMessage());
ee.printStackTrace();
}
}
}
--
Murad Nayal M.D. Ph.D.
Department of Biochemistry and Molecular Biophysics
College of Physicians and Surgeons of Columbia University
630 West 168th Street. New York, NY 10032
Tel: 212-305-6884 Fax: 212-305-6926
