VTU Distributed Computing Lab - Web Services

 Design and implement business logic and bind it as service using SOAP (Simple Object Access Protocol), also implement client to call service.

Right Click ->New Project

Select from Categories Java Web and Projects Web Application

Provide Project Name : TaxCalWebService

Click on next

Click on Finish

(New Project will be created)

Right click on project (TaxCalWebService) -> New -> WebService

Provide the Web Service Name (CalculateTaxService) and package name : ws. click on Finish

New Web Service class will created

Right click on CalculateTaxService -> Add web service operation

Provide name and parameters

New Method will be create in CalculateTaxService

Make the following code modifications in calculateTaxAmount method

We are done with the web service, Right click on the project and run.

Creating web service client project:

Right click project explorer -> New Project -> Java Web (Web Application)

Provide name of the project and click on Next

Click on Finish

Expand the client project -> Source page -> Right Click -> New -> Servlet

Provide : Class name : TaxCalServlet, package name : ws

Click on Next

Click on Finish.

In index.html page add new form in the body tag

Open the Serlvet class (TaxCalServlet) -> Right click -> Call Web Service Operation….

Then the follow Screen appears select the web service ( calculateTaxAmount) and click OK.

New private method will be added to TaxCalServlet.

Add the following code snippet in TaxCalSerlvet

We are done with the Client

Run the client program.

Source code: Download

Recursive methods in java

Recursion:

Recursion is a programming technique that allows the programmer to express operations in terms of themselves.

Recursive method to find the factorial of the number

public static int factorial(int num) {

          if (num == 0 || num == 1)

                   return 1;

          else

                   return num * factorial(num - 1);

}

Recursive method to find the sum of first N natural numbers

public static int sumofNnumber(int N) {

          if (N == 1)

                   return 1;

          else

                   return N + sumofNnumber(N - 1);

}

Recursive method to find the GCD of two numbers

public static int gcdOfNumbers(int num1, int num2) {

          if (num1 == num2)

                   return num1;

          else if (num1 > num2)

                   return gcdOfNumbers(num1 - num2, num2);

          else

                   return gcdOfNumbers(num1, num2 - num1);

}

Recursive method to multiply two numbers using Russian Peasant algorithm

public static int russianPeasantMultiply(int num1, int num2) {

          if (num1 == 1)

                   return num2;

                   else if (num1 % 2 == 1)

                             return num2 + russianPeasantMultiply(num1 / 2, num2 * 2);

                    else

                             return russianPeasantMultiply(num1 / 2, num2 * 2);

}

Recursive method to find the M^N

public static int power(int m, int n) {

                   if (n == 1)

                             return m;

                   else

                             return m * power(m, n - 1);

}

Recursion method to find the reverse of the given number

public static long reverse(long num){

          return reverse(num,0);

}

private static long reverse(long n, long m) {

          if (n == 0)

                   return m;

          else

                   return reverse(n / 10, m * 10 + n % 10);

}

VTU Distributed Computing Lab - Program 2 (EJB)

2. Design and implement EJB (Enterprise Java Beans) session bean business logic to calculate income tax and invoke the service using stub, i.e., client side proxy object.

Categories -> java and select Java Class Library and click on next

Provide name it-remote click on finish

Then screen window appears:

Create new Project:

In categories select Java EE and select Enterprise Application in Projects  

Click on next

Unselect the Create web Application Module and click on finish

Then the following project will be created in the work space…

Right click on it-sb-eap2-ejb -> new Session Bean

Provide EJB Name:

Do the following:

EJB Name: ITService

Package: ejb

Session Type:

Select only: Stateless

Create Interface:

Select only: Remote in Project

Click on Finish

Then following screen appears:

Right click on “ITService” class and click Insert Code

Select Add Business Method

Provide:

Name: calculateTax

Return Type: double

Click on Add 3 times

Change the name, type of the parameters and mark all variables as final

Note: you may get error, if it happens click on Save button

Give the implementation for “calculateTax( )” method.

Add new method to get slabRates:

Write your logic to return tax percentage based on given input.

Finally the class “ITService”  looks:

We are done with Server side.

Client Project:

Create new Project ->  Java EE -> Enterprise Application Client

Click on Next

Click on Next

Click on Finish

Right click -> Insert Code

Select Call To Enterprise Bean

Select the Project

Click on OK

Create inner class in Main:

Create constructor TaxInformation class

Right-click -> insert code ( TaxInformation class)-> Constructor…

Select all the fields

Click on Generate.

Then inner class looks

Invoke the it calculateTax method by using itService (main method)

To display information:

We are done with client.

To Run the application:

Rght-click on “it-sb-eap2” and run

Application is deployed successful, now run the client class

Right-click on “it-sb-client” and run:

Then output on the console looks: