connecting WebApplication to MySQL

[hm991]

Greetings

I'm trying to connect my WebApplication(I'm using Apache Tomcat + NetBeans) to an external MySQL database(i.e.: that which exists on the same PC but was not created by this application).
I then need to move on to making sure my MobileApplication is able to access this db. All I need to do is view the data(read), and not write or create anything.

I have the code from a book: Professional Java Mobile Programming. I need some help modifying that code, I think I need the correct link/path-which I think should include the IP address of my PC..?

Please help

[im2amit]

which I think should include the IP address of my PC..?

IP address as localhost should also work, along with port no. on which Apache Tomcat is running.

thanks,
~Amitabh

[hm991]

below is the function read() which is called by the servlet..when i run the midlet, it prints a1 only, and then goes to the last catch block, displaying "Error: IO Exception", in the emulator.
This code was originally supposed to work with a db created by this application, however I'm trying to modify it so I can use it with my MySQL db-which has already been created on this machine. Do I need the path for where MySQL is stored or something? Please have a look at the method below:

//http connection is opened using url typed into the texbox
public final static String read(String url){
String result = null;
HttpConnection hc = null;
InputStream is = null;
try{System.out.println("a1");//
hc = (HttpConnection) Connector.open(url);
System.out.println("a2");//
hc.setRequestMethod(HttpConnection.GET);
String profiles = System.getProperty("microedition.profiles");
String configuration = System.getProperty("microedition.configuration");
hc.setRequestProperty("User-Agent", "Profile/" + profiles + "Configuration/" + configuration);
String locale = System.getProperty("microedition.locale");
if (locale != null){
hc.setRequestProperty("Content-Language", locale);
}//if
String platform = System.getProperty("microedition.platform");
if(platform != null){
hc.setRequestProperty("J2ME-Platform", platform);
}
try{
if (hc.getResponseCode() == HttpConnection.HTTP_OK){
System.out.println("x1");//
is = hc.openInputStream();
InputStreamReader isReader = new InputStreamReader(is);
int len = (int) hc.getLength();
if (len > 0){System.out.println("x2");//
char[] chars = new char[len];
int actual = isReader.read(chars);
result = new String(chars);
}else{System.out.println("x3");//
StringBuffer sb = new StringBuffer();
int ch;
while ((ch = is.read()) != -1){System.out.println("x4");//
sb.append((char) ch);
}
result = sb.toString();
}
}else{System.out.println("x5");//
result = "Error: return code was " + hc.getResponseCode();
}
}catch (IOException e){
result = "Error: is the web server running?";
}finally{
if(is != null){
is.close();
}
if(hc != null){
hc.close();
}
}//finally
}catch (IOException ioe){
result = "Error: IO exception.";
}
return result;
}//read()

[im2amit]

Add some more SOP's to see on which line you are getting the exception ?

thanks,
~Amitabh

[hm991]

it's not printing a1,x1,x2,x3,x4, or x5, meaning it's not even connecting to the db
(i.e. it enters the first try block, but does not connect-lines 1,2,and 3 in the 1st try block)

[im2amit]

The check the server URL in the browser is it working ?

In perivous email you wrote "when i run the midlet, it prints a1 only"

thanks,
~Amitabh

[raj_J2ME]

SOP "a1" Should be printed,check
Can you share the URL that you are calling.

[hm991]

sorry a1 is printed

it's a2 and the rest which are not

the url I'm using is: (private final static String URL =) "jdbc:mysql://:3306/db_audiology?";

[hm991]

when i run: "http://localhost:8080/" in the browser, it runs
but MySQL url doesn't

[raj_J2ME]

Is this url-> jdbc:mysql://:3306/db_audiology? is passed to the Connection.open("");
Next to the a1 SOP

[hm991]

yes it is

[hm991]

when I pass http://localhost:8080 in the following stmt: hc = (HttpConnection) Connector.open(url);
it prints a1, a2 and the midlet reads: "Error: is the web server running?"

[im2amit]

sorry a1 is printed

it's a2 and the rest which are not

the url I'm using is: (private final static String URL =) "jdbc:mysql://:3306/db_audiology?";

You can only open HTTP Connection not jdbc connection from your midlet.

For your need, you have to run a server side script say .JSP (example getData.jsp) which connects to mysql database using JDBC and then gives the needed data to mobile client.

this url can be --> http://localhost:8080/getData.jsp



thanks,
~Amitabh

[hm991]

Thanks a lot!

I'll use a PHP script as I have no experience in JSP

[raj_J2ME]

when I pass http://localhost:8080 in the following stmt: hc = (HttpConnection) Connector.open(url);
it prints a1, a2 and the midlet reads: "Error: is the web server running?"

Hello,
If you go through the GCF framework then you will find that the Connector.open() can be used for the protocols like, http, socket, datagram.You use Connector.open as in the next code fragment, supplying a single String parameter that specifies a protocol, an address, and parameters:
For example,
* HTTP Connection: Connector.open("http://java.sun.com/wireless")
* Socket Connection: Connector.open("socket://java.sun.comort")
* Datagram Connection: Connector.open("datagram://java.sun.comort")

and other than these you can open the File Connection.And that's all.

Therefore you are passing the wrong URL.