Consuming WCF Service in Java Client

Introduction

WCF is built to support interoperability. Being just a .NET developer, it becomes very difficult to prove this concept. I created this POC with the help of one of my friends Jay D Khambholiya who is a Java developer.

This article will talk about how a WCF service can be consumed by a Java client application in following three steps:

1. Create a WCF Service
2. Host WCf Service in IIS
3. Consume WCF Service in Java Client

Step 1: Create WCF Service

• Open Visual Studio 2012 > File Menu > click New Project… > select Class Library – CalculatorService > click OK

• Delete the class - Class1.cs file that is auto-generated.
• Right-click on CalculatorService project > Add > click New Item > select WCF Service > provide Name as CalculatorService > click Add button:

• This will add the required assembly references (like, System.ServiceModel) along with a Service Contract Interface – ICalculatorService.cs and Service class – CalculatorService.cs
• Modify ICalculatorService.cs as follows:

using System.ServiceModel;
namespace CalculatorService
{
    [ServiceContract]
    public interface ICalculatorService
    {
        [OperationContract]
        int Add(int num1, int num2);
    }
} 

• Modify CalculatorService.cs as follows:

namespace CalculatorService
{
    public class CalculatorService : ICalculatorService
    {
        public int Add(int num1, int num2)
        {
            return num1 + num2;
        }
    }
}

• Build the solution by pressing [CTRL]+[SHIFT]+b or go to BUILD menu > click Build Solution option.

Step 2: Host WCF Service in IIS

• Add a new web site to host Calculator Service in IIS.
• Go to File Menu > Add > click New Web Site… > select WCF Service > provide a suitable name – CalculatorServiceIISHost > click OK:

• A new web site will be added with a service class - Service.cs and an interface - IService.cs within App_Code folder along with a Service.svc file. Since the service is already created, delete the auto created service class (Service.cs) and the interface (IService.cs) from App_Code folder.
• Right-click on CalculatorServiceIISHost project > click Add Reference > select CalculatorService > click OK:

• Open Service.svc file > Delete CodeBehind property:

<%@ ServiceHost Language="C#" Debug="true" Service="Service" CodeBehind="~/App_Code/Service.cs" %>

• Modify Service property as shown below:

<%@ ServiceHost Language="C#" Debug="true" Service="CalculatorService.CalculatorService" %>

• Modify web.config file to have the following settings:

<system.serviceModel>
    <services>
        <service name="CalculatorService.CalculatorService" 
                 behaviorConfiguration="mex">
            <endpoint address="CalculatorService" binding="basicHttpBinding"
               contract="CalculatorService.ICalculatorService"></endpoint>
            <host>
                <baseAddresses>
                    <add baseAddress="http://localhost:8080/"/>
                </baseAddresses></host>
        </service>
    </services>
    <behaviors>
        <serviceBehaviors>
            <behavior name="mex">
                <serviceMetadata httpGetBinding="true"/>
            </behavior>
        </serviceBehaviors>
    </behaviors>
</system.serviceModel>

• Now the service is ready to be hosted in IIS.
• Open IIS > right-click on Default Web Site > click Add Application… > enter Alias name – calculator > select the Physical path of the service > click OK:

• Enable Anonymous Authentication as shown below:

• Go to Content View > right-click Service.svc > click Browse:

Step 3: Consume WCF Service in Java client

• Tools Used: Eclipse Indigo, Apache Tomcat 6, Apache Axis (comes pre-installed in Eclipse Indigo)
• Create a new Dynamic Web Project in Eclipse:

• To create a WS Client, select New > Web Services > select Web Service Client > click Next button:

• Enter the WSDL path of the WCF Service > click Finish button:

• This should auto-generate the code for the WS proxy:

• Create a simple JSP page that has two text boxes and a servlet to call the “add” method via web service:
• Write the following code in WCFServlet’s doPost() method to call web service’s “add” method:

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
{
 Integer input1=Integer.parseInt(request.getParameter("input1"));
 Integer input2=Integer.parseInt(request.getParameter("input2"));
 ICalculatorServiceProxy calService=new ICalculatorServiceProxy();
 Integer result=calService.add(input1,input2);
 request.setAttribute("res", "The result is: "+result);
 RequestDispatcher rd=request.getRequestDispatcher("WSDemo.jsp");
 rd.forward(request, response);
}

• Display the result on the same page WSDemo.jsp:

Summary

This article can be referred by any project or individual to get a step-by-step guidance on how a WCF service can be created and hosted in IIS and then create a Java client application to consume the service.

History

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