I’ve been doing a fair bit with SOAP, REST and Java recently using CXF. A previous post demonstrated using CXF/JAXB to create a REST style service that returned either JSON or XML, let’s look at using Spring REST services to implement the same functionality.

Let’s start (as usual) with our pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.springframework</groupId>
    <artifactId>sample-rest-service</artifactId>
    <version>0.1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.jayway.jsonpath</groupId>
            <artifactId>json-path</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <properties>
        <java.version>1.8</java.version>
    </properties>


    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-releases</id>
            <url>https://repo.spring.io/libs-release</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-releases</id>
            <url>https://repo.spring.io/libs-release</url>
        </pluginRepository>
    </pluginRepositories>
</project>

Now we create our folder structure, so create the following from the root folder

src/main/java/demo

We’re going to need to code within the demo package.

Without the package you might see a warning “Your ApplicationContext is unlikely to start due to a @ComponentScan of the default package.”

Next up, we’ll create a service, or in Spring parlance, the controller

package demo;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class SampleController {

    @RequestMapping("/purchaseOrder")
    public PurchaseOrderType getPurchaseOrder() {
        return new PurchaseOrderType(1234);
    }
}

The PurchaseOrderType is simply the following

package demo;

public class PurchaseOrderType {

    private long _id;

    public PurchaseOrderType(long id) {
        _id = id;
    }

    public long getId() {
        return _id;
    }
}

Now we need the application to start the service

package demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

To run this we can, ofcourse, set up a configuration or from the Terminal window run

mvn spring-boot:run

Now, if we navigate to http://localhost:8080/purchaseOrder/ we should see

{"id":1234}

Now, let’s extend this to allow us to return XML. We’ll need to annotate PurchaseOrderType with the @XmlRootElement, we’ll also need a default constructor and a setter for our Id property

package demo;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class PurchaseOrderType {

    private long _id;

    public PurchaseOrderType() {
    }

    public PurchaseOrderType(long id) {
        _id = id;
    }

    public long getId() {
        return _id;
    }

    public void setId(long id) {
        _id = id;
    }
}

Changing the port of the Tomcat server

You may have noticed that when running this application we get an instance of a Tomcat server running, by default it uses port 8080, but what about if we need/want to change this. We can create an EmbeddedServletContainerCustomizer, as below.

package demo;

import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.stereotype.Component;

@Component
public class ApplicationContainer implements EmbeddedServletContainerCustomizer {

    @Override
    public void customize(ConfigurableEmbeddedServletContainer configurableEmbeddedServletContainer) {
        configurableEmbeddedServletContainer.setPort(8888);
    }
}

Code is available here https://github.com/putridparrot/blog-projects/tree/master/spring-rest