Could not load middleware layer 'com.sap.mw.jco.rfc.MiddlewareRFC' - sap

I'm using Sap Jco to connect to SAP database with the front end being Java(JSF), When I connect to SAP with:
try {
mConnection =JCO.createClient("400", // SAP client
"c3026902", // userid
"********", // password
"EN", // language
"iwdf5020", // host name
"00"); // system number
mConnection.connect();
}
catch (Exception ex) {
ex.printStackTrace();
System.exit(1);
}
Problem I'm facing is when run the application for the first time, data is displayed but when I re-run it says "Could not load middleware layer 'com.sap.mw.jco.rfc.MiddlewareRFC' "
Can any one help me in resolving the issue?????

This sounds like the API cannot load the native driver files.
The SAP Java Connector consists of a native runtime part, that does the actuall communication and a Java API that wraps this functionality with a java api.
The Java API is inside the sapjco.jar and the native drivers are e.g on windows inside librfc32.dll and sapjcorfc.dll.
Place these dll's into your system path (e.g. windows: C:\WiNDOWS\system32) and it should run.
Cheers
Sebastian

Are your DLLs located in the Windows system32 folder? If so, are you probably using the wrong architecture? (x64 DLL on 32 bit or vice versa)
Also, are the DLLs the same version as the java api? If you have SAP GUI installed there could be older DLLs around.

Defining SAP connection:
For the Version 3,0 of the sapjco library there exists plenty of useful information. To create a connection following the instructions in:
http://www.browseye.com/linkShare.html?url=http://help.sap.com/saphelp_nwpi711/helpdata/en/46/fb807cc7b46c30e10000000a1553f7/content.htm?bwsCriterion=%22Setting%20Up%20Connection%22&bwsMatch=1&bwsCriterion=%22Setting%20Up%20Connection%22&bwsMatch=1
There are a few thing that you should take into account:
Place the dll file in the same place that the jar.
The dll must be the right version for your operating system and architecture otherwise you will get a native library error.
Example of code to create a connection to the server.
public class StepByStepClient
{
static String DESTINATION_NAME1 = "ABAP_AS_WITHOUT_POOL";
static String DESTINATION_NAME2 = "ABAP_AS_WITH_POOL";
static
{
Properties connectProperties = new Properties();
connectProperties.setProperty(DestinationDataProvider.JCO_ASHOST, "ls4065");
connectProperties.setProperty(DestinationDataProvider.JCO_SYSNR, "85");
connectProperties.setProperty(DestinationDataProvider.JCO_CLIENT, "800");
connectProperties.setProperty(DestinationDataProvider.JCO_USER, "homofarber");
connectProperties.setProperty(DestinationDataProvider.JCO_PASSWD, "laska");
connectProperties.setProperty(DestinationDataProvider.JCO_LANG, "en");
createDestinationDataFile(DESTINATION_NAME1, connectProperties);
connectProperties.setProperty(DestinationDataProvider.JCO_POOL_CAPACITY, "3");
connectProperties.setProperty(DestinationDataProvider.JCO_PEAK_LIMIT, "10");
createDestinationDataFile(DESTINATION_NAME2, connectProperties);
}
static void createDestinationDataFile(String destinationName, Properties connectProperties)
{
File destCfg = new File(destinationName+".jcoDestination");
try
{
FileOutputStream fos = new FileOutputStream(destCfg, false);
connectProperties.store(fos, "for tests only !");
fos.close();
}
catch (Exception e)
{
throw new RuntimeException("Unable to create the destination files", e);
}
}
public static void step1Connect() throws JCoException
{
JCoDestination destination = JCoDestinationManager.getDestination(DESTINATION_NAME1);
System.out.println("Attributes:");
System.out.println(destination.getAttributes());
System.out.println();
}
}
In SAPJco 3.0 connections are build from the info contained in a “Destination”.
The documentation example use a properties file to save the “Destination”. However it is a non-secure way to keep connection info. As is indicated on the documentation in the hightlighted paragraph you can see on next link.
http://help.sap.com/saphelp_nwpi711/helpdata/en/48/5fb9f9b523501ee10000000a421937/content.htm?bwsCriterion=%22In%20practice%20you%20should%20avoid%20this%20for%20security%20reasons.%22&bwsMatch=1
You can keep connection info on a database or any other storage system if you create a custom “DestinationDataProvider” In the Examples provided with the SAPJco library there is an example of how to create a custom DestinationDataProvider.

Related

Python.Net PythonEngine.Initialize() crashes application without throwing exception

My application (C#, VS2017) previously targeted Python 3.5.1. I have updated the system to Python 3.7.1 and have this is causing PythonEngine.Initialize() to crash the application without throwing an exception.
One internet suggestion was to set the Python env in VS, however this causes VS2017 to close when opening Python/environments. I switched to VS2019 and encountered the same issue with the stripped down code here:
using System.Windows.Forms;
using Python.Runtime;
namespace WindowsFormsApp3
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
try
{
PythonEngine.Initialize();
}
catch (Exception e)
{
string ex = e.ToString();
}
}
}
}
Python.Net was installed successfully using:
pip install pythonnet
UPDATE Dec 2022
There are 2 optional environment strings you can use to locate the python dll.
PYTHONNET_PYDLL explicitly set the dll name
PYTHONNET_PYVER explicitly set just the version string part of the dll name
Compiling with WINDOWS, OSX or LINUX defined is not required anymore
Here's my PythonNet init function.
Note that running "pip install pythonnet" only installs the ability to load & use CLR types & assemblies from Python. To embed PythonNet in a C# app, you actually don't need to install pythonnet on the Python side.
This function uses some globals set at startup.
Program.PythonHome -- points to the Python root folder I'm using
Program.ScriptsDir -- my own app python scripts dir
Program.ApplicationName -- just my own app name
I also call PythonEngine.BeginAllowThreads(); as I'm calling from multiple threads.
public static void InitPython(Microsoft.Extensions.Logging.ILogger logger)
{
string py_home = Program.PythonHome;
string py_path = $"{py_home};";
// will be different on linux/mac
string[] py_paths = {"DLLs", "lib", "lib/site-packages", "lib/site-packages/win32"
, "lib/site-packages/win32/lib", "lib/site-packages/Pythonwin" };
foreach (string p in py_paths)
{
py_path += $"{py_home}/{p};";
}
try
{
PythonEngine.PythonPath = $"{Program.ScriptsDir};{py_path}";
PythonEngine.PythonHome = Program.PythonHome;
PythonEngine.ProgramName = Program.ApplicationName;
PythonEngine.Initialize();
PythonEngine.BeginAllowThreads();
logger.LogInformation("Python Version: {v}, {dll}", PythonEngine.Version.Trim(), Runtime.PythonDLL);
logger.LogInformation("Python Home: {home}", PythonEngine.PythonHome);
logger.LogInformation("Python Path: {path}", PythonEngine.PythonPath);
}
catch (System.TypeInitializationException e)
{
throw new Exception($"FATAL, Unable to load Python, dll={Runtime.PythonDLL}", e);
}
catch (Exception e)
{
throw new Exception($"Python initialization Exception, {e.Message}", e);
}
}

File Uploading service gets failed from android whereas works with IOS

I had created the WCF service for file uploading. Its working fine when the service hits from web application or from IOS device. But its throwing an exception when it comes from Android device.
I tried to multiparse the streamdata. Its throwing an exception as like file unavailable.
public OASIS.Entity.Shared.UserFileUpload FileUpload(Stream data, string UploadMode)
{
OASIS.Entity.Shared.UserFileUpload userFileUpload = new Entity.Shared.UserFileUpload();
try
{
MultipartParser parser = new MultipartParser(data);
string fileName = string.Empty;
string filePath = string.Empty;
string allowedExtensions = string.Empty;
int allowedFileSizeMB = 0;
if (parser.FileAvailable)
{
// File Available for IOS / Web application.
// userFileUpload
}
else
{
// From android device file is getting not available.
}
}
catch (Exception exp)
{
OASIS.Utility.ExceptionManager.HandleException(exp);
userFileUpload = null;
}
return userFileUpload;
}
Expecting it should get work for android device too.
By default, WCF does not support form data files, so it looks like you are using MultipartParser to convert form data (data from a file stream uploaded through a form-data).
If this class can handle data submitted in IOS, it should also be able to handle data submitted through forms in Andriod, after all, the HTTP protocol is cross-platform.
thereby I would like to know, how do you upload data in the Andriod system?
By adding breakpoint debugging, can you use this class to parse form data properly?
I suggest you handle the form-data by creating the service with asp.net WebAPI.
https://learn.microsoft.com/en-us/aspnet/web-api/overview/advanced/sending-html-form-data-part-2
Feel free to let me know if there is anything I can help with.

Single process C#.Net windows service is showing multiple thread in CPU resource monitor?

I have developed a C#.Net windows service which is a single process.In this I'm using 2 third party Dlls one for ZIP(Ionic) and another for Excel(EPPlus).
The .EXE job is to:
Read SDF file
Write the SDF file data to SQL Server table
Generate Excel
Create ZIP
While monitoring this particular EXE in resource monitor it is showing 10 threads are running.
Note: I have not used any threading in this application.
Is OS making it 10 threads? If yes, how and why??
Related: Why does this simple .NET console app have so many threads?
I'll use a simple console application in Visual Studio 2010 that adds a reference to an assembly that spawns a thread similar to what a 3rd party library could do.
A Windows Service may have different debugging techniques, and may have various additional threads running created by the system.
Simple Console
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
ClassLibrary1.Class1.StartThread();
while (true)
{
System.Threading.Thread.Sleep(1000);
System.Diagnostics.Trace.TraceInformation("test2");
}
}
}
}
Simple API in separate class library assembly, added as a reference to the Console project
using System.Threading.Tasks;
namespace ClassLibrary1
{
public class Class1
{
public static void StartThread()
{
var t = new Task(() => {
while(true)
{
System.Threading.Thread.Sleep(1000);
System.Diagnostics.Trace.TraceInformation("test1");
}
});
t.Start();
}
}
}
Start Debugging (F5)
From the Menu Debug, Select 'Break All'
From the Menu Debug, Select Windows then Threads
The following image shows :
Main Thread, this is the console application
ClassLibrary1.Class1.StartThread.AnonymousMethod_0, this is the thread started by the referenced assembly. If Ionic or a 3Rd party API started a thread, you may see something related to its namespace.

Exception error in google doc api

I am new to google api. I am trying to create a simple web application (Java EE) to read DocumentListFeed from google doc. My code in the servlet is:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
try
{
DocsService service = new DocsService("Document List Demo");
service.setUserCredentials(NAME, PASSWORD);
response.getWriter().println("helloooooo");
//URL documentListFeedUrl = new URL("http://docs.google.com/feeds/documents/private/full");
URL documentListFeedUrl = new URL("https://docs.google.com/feeds/default/private/full?v=3");
DocumentListFeed feed = service.getFeed(documentListFeedUrl, DocumentListFeed.class);
for(DocumentListEntry entry : feed.getEntries())
{
response.getWriter().println(entry.getTitle().getPlainText());
}
}
catch (Exception e)
{
response.getWriter().println(e);
}
}
But it is showing me the error: java.lang.NoClassDefFoundError: com/google/gdata/client/docs/DocsService
I am using Glassfish server and Ecllipse. And added external jar file: activation.jar, guava-r07.jar, mail.jar, servlet.jar, gdata-client-1.0.jar, gdata-client-meta-1.0.jar, gdata-core-1.0.jar, gdata-media-1.0.jar, gdata-docs-3.0.jar, gdata-docs-meta-3.0.jar.
I have copied this same code to java standard edition and it is working fine. Could please tell me why this thing is not working in Java EE? Is it a problem in GlassFish server?
It just means that the jars are not present in your Glassfish server classpath.
Add all the jars you listed to yuor glassfish server classpath. Since am not an Glassfish expert i cannot help you in adding the jars to your server.
In case of weblogic, you just need to package all the jars in your project APP-INF directory.
Hope it helps.

Self updating .net CF application

I need to make my CF app self-updating through the web service.
I found one article on MSDN from 2003 that explains it quite well. However, I would like to talk practice here. Anyone really done it before or does everyone rely on third party solutions?
I have been specifically asked to do it this way, so if you know of any tips/caveats, any info is appreciated.
Thanks!
This is relatively easy to do. Basically, your application calls a web service to compare its version with the version available on the server. If the server version is newer, your application downloads the new EXE as a byte[] array.
Next, because you can't delete or overwrite a running EXE file, your application renames its original EXE file to something like "MyApplication.old" (the OS allows this, fortunately). Your app then saves the downloaded byte[] array in the same folder as the original EXE file, and with the same original name (e.g. "MyApplication.exe"). You then display a message to the user (e.g. "new version detected, please restart") and close.
When the user restarts the app, it will be the new version they're starting. The new version deletes the old file ("MyApplication.old") and the update is complete.
Having an application update itself without requiring the user to restart is a huge pain in the butt (you have to kick off a separate process to do the updating, which means a separate updater application that cannot itself be auto-updated) and I've never been able to make it work 100% reliably. I've never had a customer complain about the required restart.
I asked this same question a while back:
How to Auto-Update Windows Mobile application
Basically you need two applications.
App1: Launches the actual application, but also checks for a CAB file (installer). If the cab file is there, it executes the CAB file.
App2: Actual application. It will call a web service, passing a version number to the service and retrieve a URL back if a new version exists (). Once downloaded, you can optionally install the cab file and shut down.
One potiencial issue: if you have files that one install puts on the file system, but can't overwrite (database file, log, etc), you will need two separate installs.
To install a cab: look up wceload.exe http://msdn.microsoft.com/en-us/library/bb158700.aspx
private static bool LaunchInstaller(string cabFile)
{
// Info on WceLoad.exe
//http://msdn.microsoft.com/en-us/library/bb158700.aspx
const string installerExe = "\\windows\\wceload.exe";
const string processOptions = "";
try
{
ProcessStartInfo processInfo = new ProcessStartInfo();
processInfo.FileName = installerExe;
processInfo.Arguments = processOptions + " \"" + cabFile + "\"";
var process = Process.Start(processInfo);
if (process != null)
{
process.WaitForExit();
}
return InstallationSuccessCheck(cabFile);
}
catch (Exception e)
{
MessageBox.Show("Sorry, for some reason this installation failed.\n" + e.Message);
Console.WriteLine(e);
throw;
}
}
private static bool InstallationSuccessCheck(string cabFile)
{
if (File.Exists(cabFile))
{
MessageBox.Show("Something in the install went wrong. Please contact support.");
return false;
}
return true;
}
To get the version number: Assembly.GetExecutingAssembly().GetName().Version.ToString()
To download a cab:
public void DownloadUpdatedVersion(string updateUrl)
{
var request = WebRequest.Create(updateUrl);
request.Credentials = CredentialCache.DefaultCredentials;
var response = request.GetResponse();
try
{
var dataStream = response.GetResponseStream();
string fileName = GetFileName();
var fileStream = new FileStream(fileName, FileMode.CreateNew);
ReadWriteStream(dataStream, fileStream);
}
finally
{
response.Close();
}
}
What exactly do you mean by "self-updating"? If you're referring to configuration or data, then webservices should work great. If you're talking about automatically downloading and installing a new version of itself, that's a different story.
Found this downloadable sample from Microsoft- looks like it should help.
If you want to use a third-party component, have a look at AppToDate developed by the guys at MoDaCo.