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Webservice communication between Java EE applications

I have two Java EE applications on two separate application servers. One of them already contains a working EJB. I want to be able to communicate with this EJB from the other application by using a JAX-WS webservice (the communication has to work between different application servers and different server versions, so remote EJB call is no option). It is no problem to expose the server api to the client application.
The server side is quite clear, adding #Webservice annotation seems to work quite well. But i wonder what is the best way to build the client: I don't really want to generate the client stub from the wsdl (which itself has been generated from the ejb code by the container in my case) and pack all these generated classes into the client ear - but this seems to be the only way i can make use of #WebServiceRef annotations.
The alternative to make a dynamic proxy myself with the help of the static methods of javax.xml.ws.Service (sth. like service=Service.create() and service.getPort()) is not recommended by the Spec and "container providers are not required to support managed Service Instances created using these methods".
But that is exactly sth. that I want to use:
Is there a way to get a dynamic proxy injected in my code, managed by the application server? Or is the only way to get a managed webservice client instance to be done with generated client stub classes?

Read JAX-WS 2.2 spec, Chapter 4: Client APIs.
1. Static Client Generation
Is really the simplest way to work with JAX-WS. From a web services perspective, the WSDL is the interface AND the connection properties. Even if you choose not to work with it physically, you still need to know it in a logical sense to make meaningful SOAP calls.
Note from JAX-WS spec: An Endpoint that uses the SOAP 1.1/HTTP binding MUST
make its contract available as a WSDL 1.1 document at the publishing address suffixed with ?WSDL or ?wsdl
2. Dynamic Client Programming
Is there a way to get a dynamic proxy injected in my code, managed by the application server?
This approach involves dynamic programming against the JAX-WS API to connect to a web service either with or without using WSDL. There's no way to just "inject" a dynamic proxy out of nowhere. You need to construct & configure one with the SEI's port URLs. The WSDL document is the standard place to store such configuration information, although it is possible to avoid it and to programmatically insert the info.
2A) Dynamic programming with WSDL:
javax.xml.ws.Service service = Service.create(
new URL("http://example.org/stocks.wsdl"),
new QName("http://example.org/stocks", "StockQuoteService"));
com.example.StockQuoteProvider proxy = service.getPort(portName,
com.example.StockQuoteProvider.class)
javax.xml.ws.BindingProvider bp = (javax.xml.ws.BindingProvider)proxy;
Map<String,Object> context = bp.getRequestContext();
context.setProperty("javax.xml.ws.session.maintain", Boolean.TRUE);
proxy.getLastTradePrice("ACME");
Advantages over (1): can dynamically dynamically change the WSDL doc after app is deployed, provided such changes do not affect the java interface to client.
i.e. very little benefit to you. Your WSDL is static. Whilst you could point your client to <service endpoint URL>?wsdl to dynamically lookup, this means you need to manually configure <service endpoint URL> AND that leaves little else that can change in the SEI/WSDL without impacting your client logic.
2B) Dynamic programming without WSDL:
String endpointUrl = ...;
QName serviceName = new QName("http://example.org/wssample/echo/", "EchoService");
QName portName = new QName("http://example.org/wssample/echo/", "EchoServicePort");
/** Create a service and add at least one port to it. **/
Service service = Service.create(serviceName);
service.addPort(portName, SOAPBinding.SOAP11HTTP_BINDING, endpointUrl);
/** Create a Dispatch instance from a service.**/
Dispatch<SOAPMessage> dispatch = service.createDispatch(portName,
SOAPMessage.class, Service.Mode.MESSAGE);
/** Create SOAPMessage request. **/
// compose a request message
MessageFactory mf = MessageFactory.newInstance(SOAPConstants.SOAP_1_1_PROTOCOL);
// Create a message. This example works with the SOAPPART.
SOAPMessage request = mf.createMessage();
SOAPPart part = request.getSOAPPart();
// Obtain the SOAPEnvelope and header and body elements.
SOAPEnvelope env = part.getEnvelope();
SOAPHeader header = env.getHeader();
SOAPBody body = env.getBody();
// Construct the message payload.
SOAPElement operation = body.addChildElement("invoke", "ns1",
"http://com/ibm/was/wssample/echo/");
SOAPElement value = operation.addChildElement("arg0");
value.addTextNode("ping");
request.saveChanges();
/** Invoke the service endpoint. **/
SOAPMessage response = dispatch.invoke(request);
Advantage (not really): can eventually get it to carry out same behaviour as above.
Disadvantages: Complex programming. Non-standard configuration (outside of WSDL). Need to avoid hard-coding settings. Brittle to interface changes. Manually synchronising settings between server and client - easy to omit something, extremely difficult to debug.
Answer:
Go back to (1). Generate a client stub from the WSDL. Use it as an interface contract - it should be designed well and not change.
Then spend the time you save solving real problems... ;) ;)

Slow initialization of apache cxf client

I'm using wsdl2java generated classes and this code:
MyService f = new MyService();
MyServicePortType type = f.getMyServicePortType();
Each of these calls is taking up to 30 seconds. Why is that?

After hours of googling and tinkering the problem was in how scheme files were referenced:
although WSDL and XSD were locally stored there was still some referenced to w3.org that looked like this:
<!DOCTYPE schema PUBLIC "-//W3C//DTD XMLSchema 200102//EN" "http://www.w3.org/2001/XMLSchema.dtd" [...
<import namespace="http://www.w3.org/2000/09/xmldsig#" schemaLocation="http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/xmldsig-core-schema.xsd" />
w3.org server was resposing super-slowly hence the slow initialization of my client.
I have changed the reference to local:
<import namespace="http://www.w3.org/2000/09/xmldsig#" schemaLocation="xmldsig-core-schema.xsd" />

I owe you a great debt since I have been struggling with this for days and your answer pointed me in the right direction.
Indeed w3.org URLs take ages to respond, however there is actually no reason why a SOAP client generated from a WSDL should still need to parse the WSDL at runtime.
In fact it does not, however default generated construstors force that.
I've discovered that it's possible to skip this by instantiating the service port in a different way and specify the service endpoint via request context as follows:
// creating the service this way passes null as the wsdlLocation, preventing the runtime resolution and parsing of the wsdl
Service service = ZefixService.create(ZefixService.SERVICE);
ZefixServicePortType zefixServicePort = service.getPort(ZefixServicePortType.class);
Map<String, Object> requestContext = ((BindingProvider) zefixServicePort).getRequestContext();
// because we create the service without the wsdl location, we need to specify the service base url ourselves
requestContext.put(BindingProvider.ENDPOINT_ADDRESS_PROPERTY, Configuration.get(Constants.API_BASE_URI_PROPERTY));
requestContext.put(BindingProvider.USERNAME_PROPERTY, Configuration.get(Constants.USER_PROPERTY));
requestContext.put(BindingProvider.PASSWORD_PROPERTY, Configuration.get(Constants.PASSWORD_PROPERTY));
return zefixServicePort;
I hope this turns useful for you and others in the future.
Thanks again

WebService Client in Java

I have the following problem: I am completely new to java EE (know only about servlets and JSPs) and especially web services.
I need to develop a client for a web service (it needs to query the service for useful information once in a minute).
In my mind this client would be a simple java-SWing-based program, which would query the web service through simple Socket when the application client runs. How can that be done?
Is it possible to do in that way? If not, which is the easiest way to create such a client?

I would suggest using Apache CXF. Simple and powerful framework.
And yes, that is possible to implement what you said using this framework. Just read tutorials and play around for a bit with it.

Inorder to connect to a web service using a java client follow the below mentioned steps:
1. Get the URL in which the webservice is hosted. This is usually of the fomat http://<IP_OF_SERVER>:<PORT_OF_SERVER>/<WEB_APP_NAME>?wsdl
2. Get the qualified name of the service:
// 1st arg is the service URI
// 2nd is the service name published in the WSDL
QName qname = new QName(<Service_URI>, <SERVICE_NAME_PUBLISHED_WSDL>);<br/>
3. Create a factory for the service:
Service service = Service.create(url, qname);
4. Extract the endpoint interface, the service "port":
<Port_Class_Name> eif = service.getPort(<Port_Class_Name>);
5. Now use the methods on the Port, which are the actual methods in your webservice.

You might want to try REST Webservice, try Jersey REST (or others). With rest you can connect it with http connection (GET and POST).

Inorder to connect to a web service using a java client follow the below mentioned steps:
1.URL wsdlUrl = new URL("your wsdl url);
2.QName qname = new QName("targetNamespace in ur wsdl file","service name in your wsdl file");
Service service = Services.create(wsdlUrl,qname);
4.suppose getData() is your SEI
GetData data = (GetData)service.getPort(GetData.class);
5.call the your methods using data object
ex:data.getId(String name); this will return your response

How to implement Soap Faults in Java webservices?

Am pretty new to web services and have been trying to implement Soap Faults. I used Apache Axis2 to generate webservice in the following manner.
public interface XYZ{
public String myMethod(User[] user)
}
Here I have created a User class with some variables so that I can generate User object at .Net environment to pass User[] of objects.
Public class Webservice implements XYZ
{
Public String myMethod(User[] user){
//My implementation
}
}
Now, I created a dynamic project using Eclipse and with the help of Axis2 plugin I created webservice for my "Webservice" class which generates wsdl file. I deployed the webcontent in the Tomcat folder and able to access the WSDL file in the .Net environment. I am able to pass array of objects (User[]) from .Net to Java and able to do my task. Now, I need to implement Soap Faults in Java which I am not sure how to implement.
Can anyone help me with an example or tutorial ?

Your best bet is to Google for something like "jax-ws faults". For example:
http://www.ibm.com/developerworks/webservices/library/ws-jaxws-faults/index.html
You can also implement an error handler, as discussed under "Using handlers in JAX-WS Web services" here:
http://axis.apache.org/axis2/java/core/docs/jaxws-guide.html#BottomUpService

Most frameworks will trigger a SOAP fault when you throw an Exception in the method implementing your operation. That will not give you much control on the SOAP fault content though.
See here for some details on Axis

Generally, You don't need any specific coding for implementing SOAP fault.. Whenever there is any exception thrown by the method (here myMethod in your example.), axis will automatically generate SOAPFault element in the resulting response. The exception is actually wrapped into AxisFault exception and sent to the client.
See here a i.

What's a good Java library for dynamic SOAP client operations?

I've been searching for SOAP client libraries for Java and have found a plethora of libraries based on the idea of building stub and proxy classes based on a WSDL. I'm interested in allowing the user to enter a WSDL at runtime, parsing the WSDL, then allowing the user to perform operations on the Web Service.
Does anyone know of a good SOAP client library which will allow this runtime use? Or is there a way I can use the axis2 wsdl2java functionality to build stubs into the classloader and use them at runtime?

Later than never. :)
You should achieve that in two steps:
1) parse the WSDL informed by the user to retrieve the available operations. Refer to this question to know how to do this in a simple way.
2) Create a dynamic client to send a request using the selected operations. It can be done by using the Dispatch API from Apache CXF.
Build the Dispatch object for the dynamic client (It can be created on the fly by informing web service endpoint, port name, etc):
package com.mycompany.demo;
import javax.xml.namespace.QName;
import javax.xml.ws.Service;
public class Client {
public static void main(String args[]) {
QName serviceName = new QName("http://org.apache.cxf", "stockQuoteReporter");
Service s = Service.create(serviceName);
QName portName = new QName("http://org.apache.cxf", "stockQuoteReporterPort");
Dispatch<DOMSource> dispatch = s.createDispatch(portName,
DOMSource.class,
Service.Mode.PAYLOAD);
...
}
}
Construct the request message (In the example below we are using DOMSource):
// Creating a DOMSource Object for the request
DocumentBuilder db = DocumentBuilderFactory.newDocumentBuilder();
Document requestDoc = db.newDocument();
Element root = requestDoc.createElementNS("http://org.apache.cxf/stockExample", "getStockPrice");
root.setNodeValue("DOW");
DOMSource request = new DOMSource(requestDoc);
Invoke the web service
// Dispatch disp created previously
DOMSource response = dispatch.invoke(request);
Recommendations:
Use ((BindingProvider)dispatch).getRequestContext().put("thread.local.request.context", "true"); if you want to make the Dispatch object thread safe.
Cache the Dispatch object for using later, if it is the case. The process o building the object is not for free.
Other Methods
There are other methods for creating dynamic clients, like using CXF dynamic-clients API. You can read in project's index page:
CXF supports several alternatives to allow an application to
communicate with a service without the SEI and data classes
I haven't tried that myself but should worth giving it a try.