Tag: Web Services

With all the basic configurations done as specified in the last Article we continue to develop the Business logic.

6. Create a class named Calculator.java, place four public methods add, subtract, multiply and delete and place the appropriate logics in it.

   package com.itechgenie.services.impl;
   public class Calculator {
   	public int add(int a, int b) {
   		return a+b  ;
   	}
   
   	public int subtract(int a, int b) {
   		return a-b ;
   	}
   
   	public int multiply(int a, int b) {
   		return a * b ;
   	}
   
   	public int divide(int a, int b) throws ArithmeticException {
   		return a /b ;
   	}
   }

7. This is the class that has to be exposed as the Web Service and we write the funky TestRunner.java class to do all out operations like creating WSDL file, creating stub file etc.
8. Generate WSDL file using Java2WSDL: Axis has a tool called Java2WSDL, which generates a WSDL file for a web service using a Java class. Java2WSDL file takes the following arguments.
   1. o – name for WSDL file -> calculator.wsdl
   2. n – target namespace -> mx:com.itechgenie.services.Calculator
   3. l – url of web service -> http://<host:port>/<Project-Name>/services/calculator

   Summing up the above arguments the following command line arguments is created.

   String java2wsdlArgs[] = {"-ocalculator.wsdl", "-nmx:com.itechgenie.services.Calculator", "-v", "-lhttp://localhost:8080/axis/services/calculator", "com.itechgenie.services.Calculator"} ;

   Read this Article on how to run the command line java tools from Eclipse.
   You can run the Java2WSDL as follows in the TestRunner class. Naah, don’t ask how, just put the following lines the main method and press CTRL + F11.

   try {
   	Java2WSDL.main(java2wsdlArgs) ;
   } catch (Exception e) {
   	e.printStackTrace() ;
   }

   The Java2WSDL class has the System.exit(0); method called from inside. So lines after the Java2WSDL will not be executed. To get the other arguments supported you can just run Java2WSDL.main(new String[0]) ;. This will display all the arguments supported by Java2WSDL Utility and this works for other utilities also.
   After running this Utility you will find the calculator.wsdl file created in the root folder of the Project.

9. Generate Server side and Client side codes using WSDL2Java: WSDL2Java is another tools provided by the AXIS, which can generate server side and client side Java classes using a WSDL file. These classes are needed for deploying the web service and also for accessing the web service using a Java client. This tool expects the following argument which includes the WSDL file generated in the last step.
   1. o – output folder -> src
   2. p – package for generated classes -> mx:com.itechgenie.services. generated
   3. s – generate server side classes as well
   4. *.wsdl – WSDL file of any web service

   Summing up the above arguments the following command line arguments is created.

   String wsdl2javaArgs[] = {"-osrc", "-pcom.itechgenie.generated.service", "-s", "calculator.wsdl", "-v"} ;

   Read this Article on how to run the command line java tools from Eclipse.
   Now run the WSDL2Java utility as follows.

   try {
   	WSDL2Java.main(wsdl2javaArgs) ;
   } catch (Exception e) {
   	e.printStackTrace() ;
   }

   Once the above command is run, Just refresh the project in eclipse, you will find the following files created inside the “com.itechgenie.generated.service” package.

   1. Calculator.java
   2. CalculatorService.java
   3. CalculatorServiceLocator.java
   4. CalculatorSoapBindingImpl.java
   5. CalculatorSoapBindingStub.java
   6. deploy.wsdd
   7. undeploy.wsdd

   The above files can be used in both Server and Clients side as Skeleton (CalculatorSoapBindingImpl.java) and the Stub (CalculatorSoapBindingStub.java) respectively.

10. Binding the business logic with the Skeleton: Take the Skeleton file and you will find the exact methods that were available in our Business logic class (Calculator.java.).
    Create a instance of the Business class and invoke the appropriate method from the skeleton as follows (Find the lines highlighted in yellow.).

    package com.itechgenie.generated.service;
    
    import com.itechgenie.services.Calculator;
    
    public class CalculatorSoapBindingImpl implements com.itechgenie.generated.service.Calculator{
    
    	Calculator calculatorImpl = new Calculator() ;
    
        public int add(int in0, int in1) throws java.rmi.RemoteException {
        	return calculatorImpl.add(in0, in1) ;
        }
    
        public int subtract(int in0, int in1) throws java.rmi.RemoteException {
        	return calculatorImpl.subtract(in0, in1) ;
        }
    
        public int divide(int in0, int in1) throws java.rmi.RemoteException {
        	return calculatorImpl.divide(in0, in1) ;
        }
    
        public int multiply(int in0, int in1) throws java.rmi.RemoteException {
        	return calculatorImpl.multiply(in0, in1) ;
        }
    
    }

    That’s it; we are now done with the development part of the Web Service. All we have to do is to configure to make the service up and running.

11. Last configurations to make our service available: Open the server-config.wsdd file inside the WEB-INF folder. You will find the following lines.

      <!--  Your Service from the deploy.wsdd file - Starts here -->
    
      <!--  Your Service from the deploy.wsdd file - Ends here -->

    Keep the file aside and open the deploy.wsdd from the WSDL2Java generated files. Copy the <service> … </service> tag completely and paste in between the comments said above.

12. Conclusion: You can follow the steps 6 to 11 and create as many services as you want and paste them in the server-config.wsdd.
    With this the configurations for the Web Service is over. Export the Project as a War and deploy it in Web Server and point to the URL http://<host:port>/<Project-Name>/services

This URL should display all the services generated from steps 6 to 11 with the links the WSDL files for the above.

Click here to download the sample project.