How to access methods in existing dll file from java

I have a dll file and that file contains two methods.
Now I would like to access those two methods in java program.
How to access these methods.
Give me the sample code for this problem.

http://forum.java.sun.com/thread.jspa?threadID=757125&tstart=0

Similar Messages

Calling C Functions in existing DLL's from Java

Hi Guys ,
The tutorial in this site talks about creating ur own DLL's and then calling them from Java . I need to call C functions in existing DLL's from Java . How do I go about doing this ? . Any help on this would be much appreciated.
regards
murali

What you are interested in can be done with what's called "shared stubs", from the JNI book (http://java.sun.com/products/jdk/faq/jnifaq.html), although you don't need the book to do it (I didn't).
The example code will call functions with any number and kind of parameters, but doing that requires some assembly language. They supply working examples for Win32 (Intel architecture) and Solaris (Sparc).
If you can limit yourself to functions to a single function signature (number and types of parameters), or at least a small set that you know you'll call at compile time, you can modify the example so that the assembly language part isn't needed, just straight C code.
Then you'll have one C library that you compile and a set of Java classes and you can load arbitrary functions out of arbitrary dynamic libraries. In my case you don't even have to know what the libraries and functions are ahead of time, the user can set that up in a config file.
You mentioned doing this with Delphi. One thing to watch out for is C versus Pascal (Win32) function calling convention. A good rule of thumb; if it crashes hard, you probably picked the wrong one, try the other. :-)

How to modify an existing xml file from java code.

Hi
I have worked on creating a new xml file from java code using xmlbeans.But if i try to modify an already existing file using java code I am unable to get errorfree xmlfile.
For example if xml file(studlist.xml) is as below:
<?xml version="1.0" encoding="UTF-8"?>
<StudentList xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="D:\kchaitanya\xmlprac1\abc\Studlist.xsd">
     <Student>
          <Name>ram</Name>
          <Age>27</Age>
     </Student>
<Student>
          <Name>sham</Name>
          <Age>26</Age>
     </Student>
</StudentList>
Now suppose i have set name to victor using student.setName,
and set age to 20 using setAge from javacode,
the new xml file is as follows:
<?xml version="1.0" encoding="UTF-8"?>
<StudentList xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="D:\kchaitanya\xmlprac1\abc\Studlist.xsd">
     <Student>
          <Name>ram</Name>
          <Age>27</Age>
     </Student>
<Student>
          <Name>sham</Name>
          <Age>26</Age>
     </Student>
</StudentList>
<Student>
          <Name>victor</Name>
          <Age>20</Age>
     </Student>
As observed this is not a valid xml file.But how can i modify without any errors?

I know it's an old post, but I found this while doing a google search for something else, and don't like to leave it un-aswered
Just in case anyone has a similar problem... In this case the new elements have been appended outside of the root element
What you need to do is first get the root element and then append the new children to that, there are several ways of getting the root element, which depend on what you want to do with the elements you get back here's a simple (incomplete) way.
// gets the root element of the specified file (code not shown)
Element rootElement= new SAXReader().read(file).getRootElement();Then just append the new elements as below (this is non-generic code and would need to be modified for your situation)
// write a new student element
Element student = document.createElement("Student"); // creates the new student
rootElement.appendChild(student); // ***appends it to the root element***
Element name = document.createElement("Name"); // creates the name element
name.appendChild(document.createTextNode("Fred")); // adds the name text to the name element
student.appendChild(name); // appends the name to the student
Element age= document.createElement("Age"); // creates the age element
age.appendChild(document.createTextNode("26")); // adds the age text to the age element
student.appendChild(age); // appends the name to the studentThen flush ya buffers or whatever and write the file
Edited by: Dream-Scourge on Apr 23, 2008 11:10 AM

How to access a Crystal Report .rpt file from with in SAP B1?

Dear Experts,
Please explain me the steps involved in accessing a .rpt crystal report file from within SAP B1.
Thanks in adv.
Regards
Anand

Hai Gordon,
I do not have Crystal Reports Add-on Installed on the system.
Should I get it installed on my system?
Regards
Anand

How to call a exe or bat file from java program

hi,
i actually want to know that how to call a exe or bat file from program so that i can run them parallely.

Try this :
String strCmd = "myFile.bat";
try
     Runtime rTime = Runtime.getRuntime();
     Process process = rTime.exec(strCmd);
     InputStream p_in = process.getInputStream();
     OutputStream p_out = process.getOutputStream();
     InputStream p_err = process.getErrorStream();
     p_in.close();
     p_out.close();
     p_err.close();
catch(Exception e) {
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}

Re: [SunONE-JATO] How to Access methods in the MainAppServletBase class from a view bean

OK, fair enough.
Look at the ServletConfig class.
c
Purvashada wrote:
>
We had that option. We decided against the
property files as we can get this dynamically.
There has been problems when this property
was set incorrectly at the time of installation.
Are there any api's to get the servername and
port number other than through request object..
--- "Craig V. Conover" <craig.conover@s...> wrote:
So I guess my question is, why do you need a user
request to get this
information?
You should be able to get this info when the
application is started up,
from a props file.
Does this info change from day to day? If not, why
not create a props
file on the machine that the app is running that has
this info?
Then in the servlet's init method, read this prop
file.
Does that work for you? Not sure how a user request
is needed to
determine this? If it is, please explain.
I have used this same technique for database
properties (servername,
instance name, uid, pwd, etc).
On the QA machine was the properties that pointed to
the QA database,
and on the Production machine, the property file
with the same name had
props that pointed to the Production database.
craig
Purvashada wrote:
It is a static data that is same for all theusers.
It is application level data but generateddynamically
to get the server name and the port number the appis
running on..
Thanks
--- "Craig V. Conover" <craig.conover@s...>wrote:
OK, so how does doing this only once help you.
Wouldn't you need to do
this for each individual end user?
I'm not suggesting that this is request scoped,but
maybe session scoped.
If so, then do this in the module servlet's
onNewSession event.
If this is per user, then storing it staticallyis
problematic because
all users will be using the same data which Idon't
think you want.
Let me know if my assumptions are correct.
craig
Purvashada wrote:
Basically, I need to pass the host url/request
url
to
another server which then posts the results
back to this server.
I need to get the host url dynamically.
This is what I am doing in my code to
get the host url..
URL =req.getScheme() + "://" +
req.getServerName()
+
":" + req.getServerPort();
Thanks
--- "Craig V. Conover" <craig.conover@s...>wrote:
Correct, that is a per request event.
Sounds like we need to figure out a newapproach.
Please elaborate on your requirements for
doing
whatever it is you require.
Maybe we can suggest an alternative, orperhaps
reveal that it may not
be necessary after all.
craig
Purvashada wrote:
I had added this code in the
initializeRequestContext(..)
Hoping it would be called once.
It looks like it is called for every
request.
HttpServletRequest req =requestContext.getRequest();
setActionURL(req);
If I add the code in the init() method
how can I get the HttpServletRequest
getRequest()
Thanks
--- "Craig V. Conover"
<craig.conover@s...>
wrote:
cool.
Be careful about how you update this URL
when
you
use setURL method.
The servlets in JATO are the only shared
(Application scope rather than
Request scope like ViewBeans and
Models),
and
that
you could potentially
have sync/multithread issues. You said
you
were
only
updating once at
the start of the App, so you should be
fine.
I
assume you are doing this
from an init method or init event in theservlet
class? If so, no worries.
Also, just to be sure everyone follows,
I am
not
suggesting that you
write syncronize code in the servlets asthis
will
be a potential bottle
neck in your app's scalibility. This is
not
a
JATO
shortcoming as there
are alternatives to do this sort of
coding.
craig
Purvashada wrote:
I made the method static and is
accessible..
--- "Craig V. Conover"<craig.conover@s...>
wrote:
I would assume it is a static
method, so
just
do:
MainAppServletBase.getURL()
right?
If not static, it probably should
be. If
you
feel it
should not be
static, let us know why/what your
requirements
are.
>
=== message truncated ===
To download the latest version of S1AF (JATO), please visit one of the
following locations:
Framework + IDE plugin for Sun ONE Studio 4 Update 1, Community Edition:
http://wwws.sun.com/software/download/products/Appl_Frmwk_2.0_CE.html
Framework + IDE pluign for Sun ONE Studio 4 Update 1, Enterprise Edition:
http://wwws.sun.com/software/download/products/Appl_Frmwk_2.0_EE.html
Previous versions of JATO:
http://www.sun.com/software/download/developer/5102.html

OK, fair enough.
Look at the ServletConfig class.
c
Purvashada wrote:
>
We had that option. We decided against the
property files as we can get this dynamically.
There has been problems when this property
was set incorrectly at the time of installation.
Are there any api's to get the servername and
port number other than through request object..
--- "Craig V. Conover" <craig.conover@s...> wrote:
So I guess my question is, why do you need a user
request to get this
information?
You should be able to get this info when the
application is started up,
from a props file.
Does this info change from day to day? If not, why
not create a props
file on the machine that the app is running that has
this info?
Then in the servlet's init method, read this prop
file.
Does that work for you? Not sure how a user request
is needed to
determine this? If it is, please explain.
I have used this same technique for database
properties (servername,
instance name, uid, pwd, etc).
On the QA machine was the properties that pointed to
the QA database,
and on the Production machine, the property file
with the same name had
props that pointed to the Production database.
craig
Purvashada wrote:
It is a static data that is same for all theusers.
It is application level data but generateddynamically
to get the server name and the port number the appis
running on..
Thanks
--- "Craig V. Conover" <craig.conover@s...>wrote:
OK, so how does doing this only once help you.
Wouldn't you need to do
this for each individual end user?
I'm not suggesting that this is request scoped,but
maybe session scoped.
If so, then do this in the module servlet's
onNewSession event.
If this is per user, then storing it staticallyis
problematic because
all users will be using the same data which Idon't
think you want.
Let me know if my assumptions are correct.
craig
Purvashada wrote:
Basically, I need to pass the host url/request
url
to
another server which then posts the results
back to this server.
I need to get the host url dynamically.
This is what I am doing in my code to
get the host url..
URL =req.getScheme() + "://" +
req.getServerName()
+
":" + req.getServerPort();
Thanks
--- "Craig V. Conover" <craig.conover@s...>wrote:
Correct, that is a per request event.
Sounds like we need to figure out a newapproach.
Please elaborate on your requirements for
doing
whatever it is you require.
Maybe we can suggest an alternative, orperhaps
reveal that it may not
be necessary after all.
craig
Purvashada wrote:
I had added this code in the
initializeRequestContext(..)
Hoping it would be called once.
It looks like it is called for every
request.
HttpServletRequest req =requestContext.getRequest();
setActionURL(req);
If I add the code in the init() method
how can I get the HttpServletRequest
getRequest()
Thanks
--- "Craig V. Conover"
<craig.conover@s...>
wrote:
cool.
Be careful about how you update this URL
when
you
use setURL method.
The servlets in JATO are the only shared
(Application scope rather than
Request scope like ViewBeans and
Models),
and
that
you could potentially
have sync/multithread issues. You said
you
were
only
updating once at
the start of the App, so you should be
fine.
I
assume you are doing this
from an init method or init event in theservlet
class? If so, no worries.
Also, just to be sure everyone follows,
I am
not
suggesting that you
write syncronize code in the servlets asthis
will
be a potential bottle
neck in your app's scalibility. This is
not
a
JATO
shortcoming as there
are alternatives to do this sort of
coding.
craig
Purvashada wrote:
I made the method static and is
accessible..
--- "Craig V. Conover"<craig.conover@s...>
wrote:
I would assume it is a static
method, so
just
do:
MainAppServletBase.getURL()
right?
If not static, it probably should
be. If
you
feel it
should not be
static, let us know why/what your
requirements
are.
>
=== message truncated ===
To download the latest version of S1AF (JATO), please visit one of the
following locations:
Framework + IDE plugin for Sun ONE Studio 4 Update 1, Community Edition:
http://wwws.sun.com/software/download/products/Appl_Frmwk_2.0_CE.html
Framework + IDE pluign for Sun ONE Studio 4 Update 1, Enterprise Edition:
http://wwws.sun.com/software/download/products/Appl_Frmwk_2.0_EE.html
Previous versions of JATO:
http://www.sun.com/software/download/developer/5102.html

How to call function in included dll file through java application.

Hi All,
i am trying to create an java application which call c# functions using JNI. i am completed with the code and it is running fine when i tried to run from netbeans IDE. But when i tried from Calculator.jar file, first time it throws this error:
F:\JavaProjects\Calculator\dist>Java -jar Calculator.jar
Exception in thread "main" java.lang.UnsatisfiedLinkError: no CSharpClient in java.library.path
at java.lang.ClassLoader.loadLibrary(Unknown Source)
at java.lang.Runtime.loadLibrary0(Unknown Source)
at java.lang.System.loadLibrary(Unknown Source)
at calculator.CalculatorApp.<clinit>(CalculatorApp.java:20)
After that i included that dll file in the cuurent directory. And compiled and tried to run, it throws an unexpected error:
F:\JavaProjects\Calculator\dist>Java -jar Calculator.jar
*# An unexpected error has been detected by Java Runtime Environment:*
*# Internal Error (0xe0434f4d), pid=2640, tid=3700*
*# Java VM: Java HotSpot(TM) Client VM (1.6.0_02-b06 mixed mode, sharing)*
*# Problematic frame:*
*# C [kernel32.dll+0x12a5b]*
*# An error report file with more information is saved as hs_err_pid2640.log*
*# If you would like to submit a bug report, please visit:*
*# http://java.sun.com/webapps/bugreport/crash.jsp*
Anyone have idea how to solve this error.
Thanks in advance.

This error is created whenever things go sour on the native side. The first thing you can try, and I assume you are using a Java<->C++<->C# bridge which includes two dlls, one created by C++ and another by C#. Is to make sure that the C# dll is compiled using /t:module switch during compilation.
If you are using VS2008, or VS2005, you can add a post build syntax like:
csc /t:module /out:"$(ProjectDir)$(OutDir)YourModule.dll" "$(ProjectDir)YourCSfile.cs"
Hope this helps! If not, ensure first that the native code works by creating a native test app for it.

Accessing DLL files from Java

I have a problem with Java, and the problem is that I'm trying to call a DLL file declared by C++ only but without a support for Java programs, is what I'm aiming for going to be available by using the rundll32.exe file.
Note: I'm trying to use the (skydll.dll) file for controling skystar2 DVB card.
Message was edited by:
JZoro

You cannot directly call a DLL from Java unless the DLL exposes entry points that are compatible with the JNI calling conventions.
For example a Java class calling a native function like below:
class Arguments
   private native void setArgs (String[] javaArgs);
   public static void main (String args[])
      Arguments A = new Arguments();
      newArgs[] = A.setArgs(args);
   static
      System.loadLibrary("MyArgs");
}Needs a DLL entry point with the following signature:
JNIEXPORT void JNICALL
Java_Arguments_setArgs (JNIEnv *jenv, jobject job, jobjectArray oarr) {Notice that the first parameter of the method is of type JNIEnv and the second can be either a reference to a class or Java object instance.
Jacques Gonzalez
J4SOFT

How to pass arguments to a batch file from java code

Hi
I have a batch file (marcxml.bat) which has the following excerpt :
@echo off
if x==%1x goto howto
java -cp C:\Downloads\Marcxml\marc4j.jar; C:\Downloads\Marcxml\marcxml.jar; %1 %2 %3
goto end
I'm calling this batch file from a java code with the following line of code:
Process p = Runtime.getRuntime().exec("cmd /c start C:/Downloads/Marcxml/marcxml.bat");
so ,that invokes the batch file.Till that point its ok.
since the batch file accpets arguments(%1 %2 %3) how do i pass those arguments to the batch file from my code ...???
%1 is a classname : for ex: gov.loc.marcxml.MARC21slim2MARC
%2 is the name of the input file for ex : C:/Downloads/Marcxml/source.xml
%3 is the name of the output file for ex: C:/Downloads/Marcxml/target.mrc
could someone help me...
if i include these parameters too along with the above line of code i.e
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I get the following error :
Exception in thread main java.lang.Noclassdef foundError: c:Downloads\marcxml\source/xml
could some one tell me if i'm doing the right way in passing the arguments to the batch file if not what is the right way??
Message was edited by:
justunme1

1 - create a java class (Executer.java) for example:
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class Executer {
     public static void main(String[] args) {
          try {
               for (int i = 0; i < args.length; i++) {
                    System.out.println(args);
               Class<?> c = Class.forName(args[0]);
               Class[] argTypes = new Class[] { String[].class };
               Method main = c.getDeclaredMethod("main", argTypes);
               // String[] mainArgs = Arrays.copyOfRange(args, 1, args.length); //JDK 6
               //jdk <6
               String[] mainArgs = new String[args.length - 1];
               for (int i = 0; i < mainArgs.length; i++) {
                    mainArgs[i] = args[i + 1];
               main.invoke(null, (Object) mainArgs);
               // production code should handle these exceptions more gracefully
          } catch (ClassNotFoundException x) {
               x.printStackTrace();
          } catch (NoSuchMethodException x) {
               x.printStackTrace();
          } catch (IllegalAccessException x) {
               x.printStackTrace();
          } catch (InvocationTargetException x) {
               x.printStackTrace();
          } catch (Exception e) {
               e.printStackTrace();
2 - create a .bat file:
@echo off
java -cp C:\Downloads\Marcxml\marc4j.jar; C:\Downloads\Marcxml\marcxml.jar; Executer %TARGET_CLASS% %IN_FILE% %OUT_FILE%3 - use set command to pass variable:
Open MS-DOS, and type the following:
set TARGET_CLASS=MyTargetClass
set IN_FILE=in.txt
set OUT_FILE=out.txt
Then run your .bat file (in the same ms dos window)
Hope that Helps

Calling existing .h file from Java?

Hi,
I have a C .h-file that has a method defined as follows: CPXENVptr CPXopenCPLEXdevelop(int *status_p);
How do I define the function inside Java? The return type and the parameter?

Read the JNI totorial, and many, many previous psots, about "wrapper" DLLs.

How to use a VB dll file in java

hi,
i am working on college project,In this output of calculation is not matching with college site .So any one can tell "how to use or combine a VB 'dll' file in java?".so that i can use VB 'dll' file in java to get right Output.
If possible write code or send it to "[email protected]"
Thanks
Ravi kapani

Did you try Google? And no, there is no native support for accessing .dll files from Java. That said, take a look at JNI.

How can i import dll files in java project in eclipse?

Hi All,
How can i import or link dll files in java project in eclipse?....
dll files contains
import com.ms.com.ComLib;
import com.ms.com.Variant;
import com.ms.com.ComFailException;
import com.ms.wfc.data.AdoException;
import com.ms.wfc.data.AdoEnums;
Any idea of this please tell me.....
I am using eclipse 3.4 and JRE 1.4
Is this possible?
Please tell me!!!!!!!!!!!!!
Voddapally

iMovie cannot edit mpg files, unles they come directly from a supported camera.
I would suggest that you use a free third party app to convert it.
Get MPEG Streamclip from Squared 5, which is free.
Drag you mpg clip into MPEG Streamclip.
Then, FILE/EXPORT USING QUICKTIME
Choose Apple Intermediate Codec, and save it where you can find it. You should be able to import this file into iMovie, using the FILE/IMPORT/MOVIE command.
Note: If your file is an MPEG2 clip, you may need to purchase the Apple QuickTime MPEG2 Playback Component from Apple. MPEG Streamclip will tell you if you need this. Don't buy it unless you have to. It costs about $20. You just have to install the component. MPEG Streamclip will use it in the background.

Use .dll files in Java

hi,
i have a dll file thats present some function. i called DLL file from java . i got the some errors such as
Exception in thread "main" java.lang.UnsatisfiedLinkError: Error looking up function 'USBIsConnected': The specified procedure could not be found.
but I hope with in that DLL the function present. here i have used java 1.6 version . kindly give the ideas

You need to have a good look at the JNI documentation.
It isn't nearly as simple as you appear to think.

I need to call a batch file from java and pass arguments to that Batch file

Hi,
I need to call a batch file from java and pass arguments to that Batch file.
For example say: The batch file(test.bat) contains this command: mkdir
I need to pass the name of the directory to the batch file as an argument from My Java program.
Runtime.getRuntime().exec("cmd /c start test.bat");
How to pass argument to the .bat file from Java now ?
regards,
Krish
Edited by: Krish4Java on Oct 17, 2007 2:47 PM

Hi Turing,
I am able to pass the argument directly but unable to pass as a String.
For example:
Runtime.getRuntime().exec("cmd /c start test.bat sample ");
When I pass it as a value sample, I am able to receive this value sample in the batch file. Do you know how to pass a String ?
String s1="sample";
Runtime.getRuntime().exec("cmd /c start test.bat s1 ");
s1 gets passed here instead of value sample to the batch file.
Pls let me know if you have a solution.
Thanks,
Krish

How to create a .DLL file from a .C file ?

Hi everybody
I'm looking for a method how to create a .DLL file from a .C file .That Dll file will be used to perform a board to measure voice quality accoding to the international standard named PESQ (perceptual evaluation of speech qualty) P.862.
Can anyone help to start dealing with Dlls and give some advices to avoid errors ?
thx
Attachments:
source.zip ‏37 KB

Hi sinaps,
You mention that you want to create a DLL from a .C file. Just to clarify, are you using C (.c file) or C++ (.cpp) to write your code?
Also, if you are using C++, are you using Visual Studio? (The reason I ask is because this forum is geared towards Measurement Studio, which is an add on to Microsoft Visual Studio).
That being said,
If you are using C: National Instruments provides an ANSI C Application Development Environment called LabWindows/CVI which makes building dlls a snap. It has templates for DLLs and you can build them either as stdcall or cdecl dlls.
Developer Zone Tutorial: Building a DLL with LabWindows/CVI 8.5 for use with LabVIEW 8.5
If you are using Visual C++: Look at the link that Al provided earlier.
MSDN: Walkthrough: Creating and Using a Dynamic Link Library
If you aren't using CVI or Visual Studio, then really the best bet is to do a google search for "Create C DLL" or post or a forum for the appropriate environment that you are using.
Thanks!
Message Edited by Jervin_J on 03-14-2009 02:02 PM
Jervin Justin
NI TestStand Product Manager

How to access methods in existing dll file from java

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