Java Web Services with simple types

In the previous post we created a simple Web Service in Java. Now we’ll build on it, by providing more methods with standard argument and return types.

• String
• Number
• Boolean
• Array
• Variable arguments

Let’s recall the Web Service with a single available operation.

@WebService
@SOAPBinding(style=Style.RPC)
public interface SimpleService {
   @WebMethod
   String sayHello();
}

Strings

Apart from sayHello, we would like a new operation that says hello to a given name.

@WebService
@SOAPBinding(style=Style.RPC)
public interface SimpleService {
   @WebMethod
   String sayHello();

   @WebMethod
   String sayHelloTo(String name);
}

Let’s implement it.

@WebService(endpointInterface="simple.SimpleService")
public class SimpleServiceImpl implements SimpleService {
   public String sayHello() {
      return "Hello from Web Services!";
   }
   public String sayHelloTo(String name) {
      return String.format("Hello %s!", name);
   }
}

If we publish the Web Service and access its WSDL, we’ll notice some new lines.

...
<message name="sayHelloTo">
   <part name="arg0" type="xsd:string"/>
</message>
...

Booleans and Numbers

Here is another operation that determines whether an integer is even.

public interface SimpleService {
   ...
   @WebMethod
   boolean isEven(int input);
   ...
}

Its implementation is straight-forward.

public class SimpleServiceImpl implements SimpleService {
   ...
   public boolean isEven(int input) {
      return input % 2 == 0;
   }
   ...
}

When the service is published, notice that the following lines are added to the WSDL.

...
<message name="isEven">
   <part name="arg0" type="xsd:int"/>
</message>
<message name="isEvenResponse">
   <part name="return" type="xsd:boolean"/>
</message>
...

Arrays and var-args

The last operation of our Web Service is to reverse an array.

public interface SimpleService {
   ...
   @WebMethod
   String[] reverse(String... input);
   ...
}

The equivalent entries in the WSDL contract are the following.

...
<message name="reverse">
   <part name="arg0" type="ns1:stringArray"/>
</message>
<message name="reverseResponse">
<part name="return" type="ns2:stringArray"/>
</message>
...

The complete code follows.

The Web Service:

@WebService
@SOAPBinding(style=Style.RPC)
public interface SimpleService {
   @WebMethod
   String sayHello();

   @WebMethod
   String sayHelloTo(String name);

   @WebMethod
   boolean isEven(int input);

   @WebMethod
   String[] reverse(String... input);
}

API: WebService, WebMethod, SOAPBinding, SOAPBinding.Style

@WebService(endpointInterface="simple.SimpleService")
public class SimpleServiceImpl implements SimpleService {
   public String sayHello() {
      return "Hello from Web Services!";
   }
   public String sayHelloTo(String name) {
      return String.format("Hello %s!", name);
   }
   public boolean isEven(int input) {
      return input % 2 == 0;
   }
   public String[] reverse(String... input) {
      if (input == null) return null;
      final String[] result = new String[input.length];
      for (int index = 0; index < input.length; index++) {
         result[index] = input[input.length - 1 - index];
      }
      return result;
   }
}

The publisher:

public class SimpleServicePublisher {
   /**
    * Publishes the Web Service locally.
    */
   public static void main(String[] args) {
      Endpoint.publish("http://127.0.0.1:9000/simple", new SimpleServiceImpl());
   }
}

API: Endpoint

The client:

public class SimpleServiceClient {
   public static void main(String[] args) throws Exception {
      // Connect to the Web Service
      final URL url = new URL("http://127.0.0.1:9000/simple");
      final QName name = new QName("http://simple/", "SimpleServiceImplService");
      final Service service = Service.create(url, name);
      final SimpleService simple = service.getPort(SimpleService.class);
      // Call some operations
      System.out.println(simple.sayHello());
      System.out.println(simple.sayHelloTo("Nikos"));
      int number = 32;
      System.out.format("The number %d is %seven.\n", number, simple.isEven(number) ? "" : "not ");
      String[] result = simple.reverse("Nikos", "Sofia", "Eleni");
      for (String element : result) {
         System.out.println(element);
      }
   }
}

Summary

The Web Services remain really simple, when the methods use standard Java types.

Java type	Schema type
String	string
Integer	int
Boolean	boolean
String[]	stringArray
String…	stringArray

In the next post, we’ll use more complex types; this will require just a single extra configuration step.

Thanks.

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