Web Service Implementation Bottom-up approach

1. Create Maven Dynamic web project

2. Add CXF and spring dependencies to project

Go to pom.xml and select Dependencies tab and add the below dependencies

spring-core
spring-webmvc
spring-context
cxf-rt-frontend-jaxws
cxf-rt-frontend-jaxrs
cxf-rt-transports-http

3. Create java endpoint interface, implementation classes and data transfer classes for Request and Response

Ex:

Interface

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public interface PaymentProcessor {
	public PaymentProcessorResponse processPayment(PaymentProcessorRequest request);
}

Implementation:

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package com.practice.processor;

import com.practice.processor.dto.PaymentProcessorRequest;
import com.practice.processor.dto.PaymentProcessorResponse;

public class PaymentProcessorImpl implements PaymentProcessor {

	public PaymentProcessorResponse processPayment(	PaymentProcessorRequest request) {
		PaymentProcessorResponse response = new	PaymentProcessorResponse();
		response.setSucess(true);
		return response;
	}
}

Request class

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package com.practice.processor.dto;

public class PaymentProcessorRequest {
	private CreditCardInfo creditCardInfo;
	private Double amount;
	
	public CreditCardInfo getCreditCardInfo() {
		return creditCardInfo;
	}
	public void setCreditCardInfo(CreditCardInfo creditCardInfo) {
		this.creditCardInfo = creditCardInfo;
	}
	public Double getAmount() {
		return amount;
	}
	public void setAmount(Double amount) {
		this.amount = amount;
	}	
}

Response class

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package com.practice.processor.dto;

public class PaymentProcessorResponse {
	private boolean sucess;

	public boolean isSucess() {
		return sucess;
	}

	public void setSucess(boolean sucess) {
		this.sucess = sucess;
	}
}

4. Annotate web service endpoint interface with JAXWS annotations

Use @WebService annotation for interface, @WebParam for input parameters and @WebResult for return type

Ex:

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package com.practice.processor;

import javax.jws.WebParam;
import javax.jws.WebResult;
import javax.jws.WebService;

import com.practice.processor.dto.PaymentProcessorRequest;
import com.practice.processor.dto.PaymentProcessorResponse;

@WebService(name = "PaymentProcessor")
public interface PaymentProcessor {
	public @WebResult(name = "response") PaymentProcessorResponse processPayment(
			@WebParam(name = "PaymentProcessorRequest") PaymentProcessorRequest request);

}

Note: Annotating input parameters and returns type is optional. But can be done to control the names of the corresponding message types in WSDL.

5. Annotate Request and Response beans with JAXB annotations

This should be done so that the objects can be serialized to SOAP messages and deserialized back to Java objects

Annotate each Request and Response classes with

@XmlType(name="")
@XmlAccessorType(XmlAccesssType.FIELD)

Now annotate each field in these classes with

@XmlElement(name="",required=true)

Ex: Now the above Request class will look like this.

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package com.practice.processor.dto;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlType;

@XmlType(name="PaymentProcessorRequest")
@XmlAccessorType(XmlAccessType.FIELD)
public class PaymentProcessorRequest {
	@XmlElement(name="creditCardInfo", required=true)
	private CreditCardInfo creditCardInfo;
	@XmlElement(name="amount", required=true)
	private Double amount;
	
	public CreditCardInfo getCreditCardInfo() {
		return creditCardInfo;
	}
	public void setCreditCardInfo(CreditCardInfo creditCardInfo) {
		this.creditCardInfo = creditCardInfo;
	}
	public Double getAmount() {
		return amount;
	}
	public void setAmount(Double amount) {
		this.amount = amount;
	}	
}

Note: Annotating fields is not mandatory for simple types.

6. Configure CXFServlet in deployment descriptor

Add the below lines to web.xml file to configure CXFServlet

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
	xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" 
	version="3.1">
 
	<display-name>javafirstws</display-name>
	<servlet>
		<servlet-name>CXFServlet</servlet-name>
		<servlet-class>org.apache.cxf.transport.servlet.CXFServlet</servlet-class>
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>CXFServlet</servlet-name>
		<url-pattern>/services/*</url-pattern>
	</servlet-mapping> 
</web-app>

7. Add cxf-servlet.xml CXF spring bean configuration file

Select project and press Ctrl + N. Now select Spring Bean configuration File option and press Next

Now give the file name as cxf-servlet.xml and click on Next

Now select the following namespaces

beans
core
jaxrs
jaxws
soap

**8. Publish the web service endpoint as web service using cxf-servlet.xml configuration file**

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cxf="http://cxf.apache.org/core"
xmlns:jaxrs="http://cxf.apache.org/jaxrs"
xmlns:jaxws="http://cxf.apache.org/jaxws"
xmlns:soap="http://cxf.apache.org/bindings/soap"
xsi:schemaLocation="http://cxf.apache.org/jaxws http://cxf.apache.org/schemas/jaxws.xsd
http://cxf.apache.org/core http://cxf.apache.org/schemas/core.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://cxf.apache.org/jaxrs http://cxf.apache.org/schemas/jaxrs-common.xsd
http://cxf.apache.org/bindings/soap http://cxf.apache.org/schemas/configuration/soap.xsd">

	<!-- 	
	<jaxws:server id="payentService" serviceClass="com.practice.processor.PaymentProcessor" address="/paymentProcessor">
			<jaxws:serviceBean>
				<bean class="com.practice.processor.PaymentProcessorImpl"/>
			</jaxws:serviceBean>
	</jaxws:server> 
	
	-->
	
	<jaxws:endpoint id="paymentService" 
		implementor="com.practice.processor.PaymentProcessorImpl"		 
		address="/paymentProcessor">
	</jaxws:endpoint>
	
	<cxf:bus>
		<cxf:features>
			<cxf:logging/>
		</cxf:features>
	</cxf:bus>
	
</beans>

9. Access the WSDL and verify everything is working

Add index.jsp file under webapp directory. Add the below to jsp which gives the access to the /services/ url to view all the services list.

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<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>

<h1> Test application</h1>
<a href="${pageContext.servletContext.contextPath}/services">Available services</a>

10. Now build the application and run on server to see the below.

Clicking on link would show our web service

Java for lazy readers

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