how to call a web service (described by a wsdl) from java

Question

Knowing nothing of web services, I'm just trying to call some "isAlive" service that is described by a wsdl.
This seems to me like something that should take more then 2-5 lines of code but I can't seem to find anything but huge long examples involving 3rd party packages etc.
anyone has any ideas?
If it is always suppose to be long maybe a good explanation as to why it has to be so complecated will also be appreciated.

I'm using eclipse and the wsdl is SOAP

thanks!!

Answer 1

There are plugins for IDE's which generate the needed code to consume a web service for you.

After the plugin generates you the base methods you simply call a web service like that:

TransportServiceSoap service = new TransportServiceLocator().getTransportServiceSoap();
service.getCities();

Have a look at http://urbas.tk/index.php/2009/02/20/eclipse-plug-in-as-a-web-service-client/

Answer 2

JDK 6 comes with jax-ws, everything you need to develop a client for a web service.

I'm unable to find some simple enough examples to post , but start at https://jax-ws.dev.java.net/

Edit: here's a simple example - a client for this web service: http://xmethods.com/ve2/ViewListing.po?key=427565

C:\temp> md generated
C:\temp>"c:\Program Files\Java\jdk1.6.0_17"\bin\wsimport -keep -d generated http://www50.brinkster.com/vbfacileinpt/np.asmx?wsdl

Create PrimeClient.java which look like:

import javax.xml.ws.WebServiceRef;
import com.microsoft.webservices.*; 
//the above namespace is from the generated code from the wsdl. 

public class PrimeClient {
 //Cant  get this to work.. @WebServiceRef(wsdlLocation="http://www50.brinkster.com/vbfacileinpt/np.asmx?wsdl")
  static PrimeNumbers service;

  public static void main(String[] args) {
    try {
    service = new PrimeNumbers();
      PrimeClient client = new PrimeClient();
      client.doTest(args);
    } catch(Exception e) {
      e.printStackTrace();
    }
  }

  public void doTest(String[] args) {
    try {
      System.out.println("Retrieving the port from the following service: " + service);
      PrimeNumbersSoap pm = service.getPrimeNumbersSoap();
      System.out.println("Invoking the getPrimeNumbersSoap operation ");
      System.out.println(pm.getPrimeNumbers(100));
    } catch(Exception e) {
      e.printStackTrace();
    }
  }
}

Compile and run:

C:\temp>"c:\Program Files\Java\jdk1.6.0_17"\bin\javac -cp generated PrimeClient.java
C:\temp>"c:\Program Files\Java\jdk1.6.0_17"\bin\java -cp .;generated PrimeClient
Retrieving the port from the following service: com.microsoft.webservices.PrimeN
umbers@19b5393
Invoking the getPrimeNumbersSoap operation
1,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97

Answer 3

There are three ways to write a web service client

1. Dynamic proxy
2. Dynamic invocation interface (DII)
3. Application client

Example for Dynamic Proxy Client

import java.net.URL;

import javax.xml.rpc.Service;

import javax.xml.rpc.JAXRPCException;

import javax.xml.namespace.QName;

import javax.xml.rpc.ServiceFactory;

import dynamicproxy.HelloIF;

public class HelloClient {

public static void main(String[] args) {
    try {

        String UrlString = "Your WSDL URL";  // 
        String nameSpaceUri = "urn:Foo";
        String serviceName = "MyHelloService";
        String portName = "HelloIFPort";

        System.out.println("UrlString = " + UrlString);
        URL helloWsdlUrl = new URL(UrlString);

        ServiceFactory serviceFactory =
            ServiceFactory.newInstance();

        Service helloService =
            serviceFactory.createService(helloWsdlUrl, 
            new QName(nameSpaceUri, serviceName));

        dynamicproxy.HelloIF myProxy = 
            (dynamicproxy.HelloIF) 
            helloService.getPort(
            new QName(nameSpaceUri, portName), 
            dynamicproxy.HelloIF.class); 

        System.out.println(myProxy.sayHello("Buzz"));

    } catch (Exception ex) {
        ex.printStackTrace();
    } 
}

}

I hope , this would solve your question.

Answer 4

The easiest I've found so far to use is the Idea IntelliJ wizard which - using Metro libraries - generate a very small code snippet which works fine with Java 6.