gs-consuming-web-service

---
tags: [SOAP]
projects: [spring-ws]
---
:spring_version: current
:toc:
:project_id: gs-consuming-web-service
:spring_version: current
:spring_boot_version: 1.4.2.RELEASE
:icons: font
:source-highlighter: prettify

This guide walks you through the process of consuming a link:/understanding/SOAP[SOAP-based web service] with Spring.

== What you'll build

You will build a client that fetches weather data from a remote, WSDL-based web service using http://en.wikipedia.org/wiki/SOAP[SOAP].
You can find out more about the weather service at http://wiki.cdyne.com/index.php/CDYNE_Weather

The service provides weather forecasts based on a zipcode. You will be able to use your own zip code.


== What you'll need

:java_version: 1.8
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NOTE: If you read link:/guides/gs/producing-web-service[Producing a SOAP web service], you might be wondering why this guide doesn't use *spring-boot-starter-ws*? That Spring Boot starter is
only for server-side web services. That starter brings on board things like embedded Tomcat, which isn't need to make a web call.


[[initial]]
== Generate domain objects based on a WSDL

The interface to a SOAP web service is captured in a http://en.wikipedia.org/wiki/Web_Services_Description_Language[WSDL]. JAXB provides an easy means to generate Java classes from a WSDL (or rather: the XSD contained in the `<Types/>` section of the WSDL).
The WSDL for the weather service can be found at http://wsf.cdyne.com/WeatherWS/Weather.asmx?wsdl.

To generate Java classes from the WSDL in maven, you need the following plugin setup:

[source,xml,indent=0]
----
include::complete/pom.xml[tags=wsdl]
----

This setup will generate classes for the WSDL found at the specified URL, putting those classes in the `hello.wsdl` package.

To do the same with gradle, you will need the following in your build file:

[source,java,indent=0]
----
include::complete/build.gradle[tags=wsdl]
----

As gradle does not have a JAXB plugin (yet), it involves an ant task, which makes it a bit more complex than in maven.

In both cases, the JAXB domain object generation process has been wired into the build tool's lifecycle so there are no extra steps to run.

== Create a weather service client

To create a web service client, you simply have to extend the http://docs.spring.io/spring-ws/sites/2.0/apidocs/org/springframework/ws/client/core/support/WebServiceGatewaySupport.html[WebServiceGatewaySupport] class and code your operations:

`src/main/java/hello/WeatherClient.java`
[source,java]
----
include::complete/src/main/java/hello/WeatherClient.java[]
----

The client contains two methods: `getCityForecastByZip` which does the actual SOAP exchange, and `printResponse` which prints the received response. We will focus on the former method.

In this method, both the `GetCityForecastByZIP` and the `GetCityForecastByZIPResponse` classes are derived from the WSDL and were generated in the JAXB generation process described in the previous step.
It creates the `GetCityForecastByZIP` request object and set it with the `zipCode` parameter.
After printing out the zip code, it uses the http://docs.spring.io/spring-ws/sites/2.0/apidocs/org/springframework/ws/client/core/WebServiceTemplate.html[WebServiceTemplate] supplied by the `WebServiceGatewaySupport` base class to do the actual SOAP exchange.
It passes the `GetCityForecastByZIP` request object, as well as a `SoapActionCallback` to pass on a http://www.w3.org/TR/2000/NOTE-SOAP-20000508/#_Toc478383528[SOAPAction] header with the request, as the WSDL described that it needed this header in the `<soap:operation/>` elements.
It casts the response into a `GetCityForecastByZIPResponse` object, which is then returned.

== Configuring web service components

Spring WS uses Spring Framework's OXM module which has the `Jaxb2Marshaller` to serialize and deserialize XML requests.

`src/main/java/hello/WeatherConfiguration.java`
[source,java]
----
include::complete/src/main/java/hello/WeatherConfiguration.java[]
----

The `marshaller` is pointed at the collection of generated domain objects and will use them to both serialize and deserialize between XML and link:/understanding/POJO[POJOs].

The `weatherClient` is created and configured with the URI of the weather service shown up above. It is also configured to use the JAXB marshaller.

== Make the application executable

This application is packaged up to run from the console and retrieve a single weather forecast for a given zip code.

`src/main/java/hello/Application.java`
[source,java]
----
include::complete/src/main/java/hello/Application.java[]
----

The `main()` method defers to the http://docs.spring.io/spring-boot/docs/{spring_boot_version}/api/org/springframework/boot/SpringApplication.html[`SpringApplication`] helper class, providing `WeatherConfiguration.class` as an argument to its `run()` method. This tells Spring to read the annotation metadata from `WeatherConfiguration` and to manage it as a component in the link:/understanding/application-context[Spring application context].

NOTE: This application is hard coded to look up zip code 94304, Palo Alto, CA. Towards the end of this guide, you'll see how to plug in a different zip code without editing the code.

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Logging output is displayed. The service should be up and running within a few seconds.

```
Requesting forecast for 94304

Forecast for Palo Alto, CA
2013-01-03 Partly Cloudy °-57° 
2013-01-04 Partly Cloudy 41°-58° 
2013-01-05 Partly Cloudy 41°-59° 
2013-01-06 Partly Cloudy 44°-56° 
2013-01-07 Partly Cloudy 41°-60° 
2013-01-08 Partly Cloudy 42°-60° 
2013-01-09 Partly Cloudy 43°-58° 
```

You can plug in a different zip code by typing `java -jar build/libs/gs-consuming-web-service-0.1.0.jar 34769`

```
Requesting forecast for 34769

Forecast for Saint Cloud, FL
2014-02-18 Sunny 51°-79° 
2014-02-19 Sunny 55°-81° 
2014-02-20 Sunny 59°-84° 
2014-02-21 Partly Cloudy 63°-85° 
2014-02-22 Partly Cloudy 63°-84° 
2014-02-23 Partly Cloudy 63°-82° 
2014-02-24 Partly Cloudy 62°-80° 
```

== Summary

Congratulations! You've just developed a client to consume a SOAP-based web service with Spring. 





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