How to invoke C DLLs from a JSP

[Mohan]

Hi there,

My name is Mohan, from Singapore. I like to know if you can help me with
the following problem. I am prepared to pay for this.
A description of the requirements are given in detail as follows :-

I need a JSP page to call a C compiled DLL from server. We like you to help
us with the development of this program.

Basically, what we want is this :-

Develop a rough and ready JSP page which has 2 text boxes, TA (input) and
TB (output). TA is an input textbox wherein the user enters a value, say
"Hello World". A command button must be provided which upon pressing will
call a DLL (developed and compiled thru a C language compiler eg, Visual
C++). NOTE : The invokation of the DLL must be done using Javascript or pure
Java.

The DLL residing in the server must be developed in C language. No other
language will do other than Microsoft C or Visual C++.
The function of the DLL could simply be to change the order of words in the
string. Once this function has performed the task, it outputs the result
into TB which then gets displayed to the user. In the case of the example
it will be "World Hello".

We need to find out from your example a couple of things :-
a) How the Java code in JSP page will call the C DLL file and pass the string
as the argument into the DLL.
b) How the DLL can be compiled in C language using Visual C++ 6.0.
c) How the output will be passed back to the JSP page.

Let me know if you can help me out on this task and what is the charge. I
like to know the charge before you start this assignment.
Note : I don't want a program that works under MS-DOS running in console.
This is useless to me. I specifically want a
JSP page calling a C language DLL.

Cheers,

Mohan

[Ruchi Dhar]

If you want invoke the DLL from servlet/JSP you need to check with your servlet/jsp
container for the JNI support. If your container support JNI calls then
its very simple to invoke dll from servlet/jsp. Try to have one wrapper
class with all the decleration of the native class like the following

public class DLLComunicator
{
//Delcare all your methods which are being exported from the DLL.
public native String methodCall1(String name);

static
{
//Load the dll with the name of the dll
System.loadLibrary("Communicator");
}
}

You can refer the JNI tutorial

http://java.sun.com/docs/books/tutor...1.1/index.html

From servlet/jsp you just create the instance of the class DLLComunicator
and invoke the methods. Its just simple java object creation and method
invocations.

The only thing you need to remember is your container should support JNI.

"Mohan" <score@singnet.com.sg> wrote:
>
>Hi there,
>
>My name is Mohan, from Singapore. I like to know if you can help me with
>the following problem. I am prepared to pay for this.
>A description of the requirements are given in detail as follows :-
>
>I need a JSP page to call a C compiled DLL from server. We like you to help
>us with the development of this program.
>
>Basically, what we want is this :-
>
>Develop a rough and ready JSP page which has 2 text boxes, TA (input) and
>TB (output). TA is an input textbox wherein the user enters a value, say
>"Hello World". A command button must be provided which upon pressing will
>call a DLL (developed and compiled thru a C language compiler eg, Visual
>C++). NOTE : The invokation of the DLL must be done using Javascript or
pure
>Java.
>
>The DLL residing in the server must be developed in C language. No other
>language will do other than Microsoft C or Visual C++.
>The function of the DLL could simply be to change the order of words in
the
>string. Once this function has performed the task, it outputs the result
>into TB which then gets displayed to the user. In the case of the example
>it will be "World Hello".
>
>We need to find out from your example a couple of things :-
>a) How the Java code in JSP page will call the C DLL file and pass the string
>as the argument into the DLL.
>b) How the DLL can be compiled in C language using Visual C++ 6.0.
>c) How the output will be passed back to the JSP page.
>
>Let me know if you can help me out on this task and what is the charge.
I
>like to know the charge before you start this assignment.
>Note : I don't want a program that works under MS-DOS running in console.
>This is useless to me. I specifically want a
>JSP page calling a C language DLL.
>
>Cheers,
>
>Mohan

[mhcox]

"Ruchi Dhar" <rdhar@verticalnet.com> wrote:
>
>If you want invoke the DLL from servlet/JSP you need to check with your
servlet/jsp
>container for the JNI support. If your container support JNI calls then
>its very simple to invoke dll from servlet/jsp

I don't think that's what Mohan is asking. What you describe is how to have
a JSP call C code *on the server*. It sounds to me that Mohan wants Java/JavaScript
and the C DLL downloaded via HTML to the client and the code execute *on
the client*.

I don't know the answer to this question and will be anxiously waiting for
the reply (interesting problem) ;-).

Mike

[Paul Clapham]

mhcox <mhcox@acm.org> wrote in message news:3a72b42c@news.devx.com...
>
> "Ruchi Dhar" <rdhar@verticalnet.com> wrote:
> >
> >If you want invoke the DLL from servlet/JSP you need to check with your
> servlet/jsp
> >container for the JNI support. If your container support JNI calls then
> >its very simple to invoke dll from servlet/jsp
>
> I don't think that's what Mohan is asking. What you describe is how to
have
> a JSP call C code *on the server*. It sounds to me that Mohan wants
Java/JavaScript
> and the C DLL downloaded via HTML to the client and the code execute *on
> the client*.
>
> I don't know the answer to this question and will be anxiously waiting for
> the reply (interesting problem) ;-).
>
> Mike
>
I don't agree with that. Here's an excerpt from Mohan's spec:

"a) How the Java code in JSP page will call the C DLL file and pass the
string
as the argument into the DLL."

This Java code is running on the server, and so it would be calling a DLL on
the server.

However, I don't intend to bid on this project. Best of luck to anyone who
does!

[David]

Hi Mohan,

This is David from Singapore.
My method is: use VB or Visual C++ to create the DLL and compile as COM
object.
Next, use the free download, "Java com-bridge" (actual name I'm not too sure)
to access the COM object.

Good luck!


"Mohan" <score@singnet.com.sg> wrote:
>
>Hi there,
>
>My name is Mohan, from Singapore. I like to know if you can help me with
>the following problem. I am prepared to pay for this.
>A description of the requirements are given in detail as follows :-
>
>I need a JSP page to call a C compiled DLL from server. We like you to help
>us with the development of this program.
>
>Basically, what we want is this :-
>
>Develop a rough and ready JSP page which has 2 text boxes, TA (input) and
>TB (output). TA is an input textbox wherein the user enters a value, say
>"Hello World". A command button must be provided which upon pressing will
>call a DLL (developed and compiled thru a C language compiler eg, Visual
>C++). NOTE : The invokation of the DLL must be done using Javascript or
pure
>Java.
>
>The DLL residing in the server must be developed in C language. No other
>language will do other than Microsoft C or Visual C++.
>The function of the DLL could simply be to change the order of words in
the
>string. Once this function has performed the task, it outputs the result
>into TB which then gets displayed to the user. In the case of the example
>it will be "World Hello".
>
>We need to find out from your example a couple of things :-
>a) How the Java code in JSP page will call the C DLL file and pass the string
>as the argument into the DLL.
>b) How the DLL can be compiled in C language using Visual C++ 6.0.
>c) How the output will be passed back to the JSP page.
>
>Let me know if you can help me out on this task and what is the charge.
I
>like to know the charge before you start this assignment.
>Note : I don't want a program that works under MS-DOS running in console.
>This is useless to me. I specifically want a
>JSP page calling a C language DLL.
>
>Cheers,
>
>Mohan

[Jun]

Hi Mohan:

Here are two commercial Java COM bridge software:

Halcyon Software
Chilisoft

Go to their company web site, download the free trial version.

Good Luck.

Jun


"David" <anjas@catcha.com> wrote:
>
>Hi Mohan,
>
>This is David from Singapore.
>My method is: use VB or Visual C++ to create the DLL and compile as COM
>object.
>Next, use the free download, "Java com-bridge" (actual name I'm not too
sure)
>to access the COM object.
>
>Good luck!
>
>
>"Mohan" <score@singnet.com.sg> wrote:
>>
>>Hi there,
>>
>>My name is Mohan, from Singapore. I like to know if you can help me with
>>the following problem. I am prepared to pay for this.
>>A description of the requirements are given in detail as follows :-
>>
>>I need a JSP page to call a C compiled DLL from server. We like you to
help
>>us with the development of this program.
>>
>>Basically, what we want is this :-
>>
>>Develop a rough and ready JSP page which has 2 text boxes, TA (input) and
>>TB (output). TA is an input textbox wherein the user enters a value, say
>>"Hello World". A command button must be provided which upon pressing will
>>call a DLL (developed and compiled thru a C language compiler eg, Visual
>>C++). NOTE : The invokation of the DLL must be done using Javascript or
>pure
>>Java.
>>
>>The DLL residing in the server must be developed in C language. No other
>>language will do other than Microsoft C or Visual C++.
>>The function of the DLL could simply be to change the order of words in
>the
>>string. Once this function has performed the task, it outputs the result
>>into TB which then gets displayed to the user. In the case of the example
>>it will be "World Hello".
>>
>>We need to find out from your example a couple of things :-
>>a) How the Java code in JSP page will call the C DLL file and pass the
string
>>as the argument into the DLL.
>>b) How the DLL can be compiled in C language using Visual C++ 6.0.
>>c) How the output will be passed back to the JSP page.
>>
>>Let me know if you can help me out on this task and what is the charge.
>I
>>like to know the charge before you start this assignment.
>>Note : I don't want a program that works under MS-DOS running in console.
>>This is useless to me. I specifically want a
>>JSP page calling a C language DLL.
>>
>>Cheers,
>>
>>Mohan
>

[Harkishin Nachnani]

Hi Mohan:
I can do it for you...and I will charge you 200 US $ for it or Rs 10,000/-
whatever currency is convenient to you. You can even pay me in equivalent
singapore dollars. Send me a confirmation note and I will start working on
it.

Cheers
Harkishin


"Mohan" <score@singnet.com.sg> wrote:
>
>Hi there,
>
>My name is Mohan, from Singapore. I like to know if you can help me with
>the following problem. I am prepared to pay for this.
>A description of the requirements are given in detail as follows :-
>
>I need a JSP page to call a C compiled DLL from server. We like you to help
>us with the development of this program.
>
>Basically, what we want is this :-
>
>Develop a rough and ready JSP page which has 2 text boxes, TA (input) and
>TB (output). TA is an input textbox wherein the user enters a value, say
>"Hello World". A command button must be provided which upon pressing will
>call a DLL (developed and compiled thru a C language compiler eg, Visual
>C++). NOTE : The invokation of the DLL must be done using Javascript or
pure
>Java.
>
>The DLL residing in the server must be developed in C language. No other
>language will do other than Microsoft C or Visual C++.
>The function of the DLL could simply be to change the order of words in
the
>string. Once this function has performed the task, it outputs the result
>into TB which then gets displayed to the user. In the case of the example
>it will be "World Hello".
>
>We need to find out from your example a couple of things :-
>a) How the Java code in JSP page will call the C DLL file and pass the string
>as the argument into the DLL.
>b) How the DLL can be compiled in C language using Visual C++ 6.0.
>c) How the output will be passed back to the JSP page.
>
>Let me know if you can help me out on this task and what is the charge.
I
>like to know the charge before you start this assignment.
>Note : I don't want a program that works under MS-DOS running in console.
>This is useless to me. I specifically want a
>JSP page calling a C language DLL.
>
>Cheers,
>
>Mohan