Create Web Service From Wsdl Java

How to invoke Java web service in using C CodeProject

Introduction

Web services are an essential part of modern software development. They allow different systems to communicate with each other over the internet, making it possible to build complex, distributed applications. In this tutorial, we will learn how to create a web service from a WSDL (Web Services Description Language) file using Java.

What is WSDL?

WSDL is an XML-based language used to describe web services. It contains information about the service, such as its methods, inputs, and outputs, and provides a way for clients to interact with the service. WSDL files are typically generated by a tool or framework that exposes a Java class as a web service.

Creating a Web Service from WSDL

To create a web service from a WSDL file using Java, we need to follow these steps:

Step 1: Generate Java Code

The first step is to generate Java code from the WSDL file using a tool such as Apache CXF or JAX-WS. This code will contain the service interface, implementation, and any necessary data types. Once the code is generated, we can customize it as needed.

Step 2: Implement the Service

Next, we need to implement the service interface. This involves writing the code to handle each method defined in the WSDL file. We can use any Java framework we like to implement the service, such as Spring or Jakarta EE.

Step 3: Publish the Service

Once the service is implemented, we need to publish it so that clients can access it. We can do this using a web server such as Apache Tomcat or Jetty. We simply deploy the service to the server and make sure it is configured correctly.

Example

Let’s look at a simple example to see how this works in practice. Suppose we have a WSDL file that defines a service with a single method called “greet”. The method takes a string parameter and returns a string. First, we generate Java code from the WSDL file using Apache CXF: “` $ wsdl2java -d src -p com.example.wsdl http://example.com/service.wsdl “` This generates the Java code in the “src” directory under the package “com.example.wsdl”. Next, we implement the service interface: “` package com.example.wsdl; import javax.jws.WebService; @WebService(endpointInterface =”com.example.wsdl.Greeter”) public class GreeterImpl implements Greeter { @Override public String greet(String name) { return “Hello, ” + name + “!”; } } “` This is a simple implementation that just returns a greeting with the name parameter. Finally, we publish the service using Apache Tomcat: “` package com.example.wsdl; import javax.xml.ws.Endpoint; public class ServicePublisher { public static void main(String[] args) { Endpoint.publish(“http://localhost:8080/service”, new GreeterImpl()); } } “` This publishes the service at “http://localhost:8080/service”. Clients can now access the service using a tool such as SOAPUI or by generating client code from the WSDL file.

Conclusion

Creating a web service from a WSDL file using Java is a straightforward process. We can use tools such as Apache CXF and JAX-WS to generate Java code from the WSDL file, and any Java framework to implement the service. Once the service is implemented, we can publish it to a web server such as Apache Tomcat and make it available to clients.