JAXB unmarshalling with xml using spring integration

Question

I am trying to create application which parses xml file and also trying to do unmarshalling to create POJO's (objects) for this xml and print it to console (toString). This is xml I am working with its from stackoverflow:

<?xml version="1.0" encoding="utf-8"?>
<feed feedid="5151"
      xmlns="http://www.w3.org/2005/Atom">
<title type="text">How to get the feed URL(s) from a website? - Stack Overflow</title>
<subtitle>most recent 30 from stackoverflow.com</subtitle>
<updated>2020-11-29T17:18:01Z</updated>
<id>https://stackoverflow.com/feeds/question/49479712</id>
<entry>
    <id>https://stackoverflow.com/q/49479712</id>
    <title type="text">How to get the feed URL(s) from a website?</title>
    <name>yPhil</name>
    <published>2018-03-25T18:58:26Z</published>
    <updated>2018-05-21T19:39:17Z</updated>
</entry>
<entry>
    <id>https://stackoverflow.com/questions/49479712/-/49479747#49479747</id>
    <title type="text">Answer by Quentin for How to get the feed URL(s) from a website?</title>
    <name>Quentin</name>
    <published>2018-03-25T19:01:00Z</published>
    <updated>2018-03-25T19:01:00Z</updated>
</entry>
</feed>

I have also made setters and getters for them:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = { "id", "title", "subtitle", "updated", "entry" })
@XmlRootElement(name="feed")
public class Feed {

    @XmlElement(required = true)
    protected int id;
    @XmlElement(required = true)
    protected String title;
    @XmlElement(required = true)
    protected String subtitle;
    @XmlElement(required = true)
    protected String updated;
    @XmlElement(required = true)
    protected List<Entry> entry;

   ...Setters and getters...

    @XmlAccessorType(XmlAccessType.FIELD)
    @XmlType(name = "", propOrder = { "id", "title", "name", "published", "updated" })
    public static class Entry{

        @XmlElement(required = true)
        protected String id;
        @XmlElement(required = true)
        protected String title;
        @XmlElement(required = true)
        protected String name;
        @XmlElement(required = true)
        protected String published;
        @XmlElement(required = true)
        protected String updated;

        ...Setters and getters...

        @Override
        public String toString() {
            return "Entry{" +
                    "entryId='" + id + '\'' +
                    ", title='" + title + '\'' +
                    ", name='" + name + '\'' +
                    ", published='" + published + '\'' +
                    ", entryUpdated='" + updated + '\'' +
                    '}';
        }
    }
    @Override
    public String toString() {
       return "Feed{" +
                "id=" + id +
                ", title='" + title + '\'' +
                ", subtitle='" + subtitle + '\'' +
                ", updated='" + updated + '\'' +
                ", entry=" + entry +
                '}';
    }
}

Also I have made configuration file for this to work and I am using spring integration for this.

 <int-file:inbound-channel-adapter id="file-producer" channel="inboundChannel"
                                      directory="src/main/resources/xmlfeed" prevent-duplicates="true">
        <int:poller fixed-rate="5000"/>
    </int-file:inbound-channel-adapter>

    <int:channel id="inboundChannel"/>


    <int-file:file-to-string-transformer id="file-2-string" input-channel="inboundChannel"
                                         output-channel="xml-inboundChannel" charset="UTF-8"/>

    <int:channel id="xml-inboundChannel"/>
    
    <int-xml:unmarshalling-transformer id="xml-2-object" input-channel="xml-inboundChannel"
                                       output-channel="outboundChannel" unmarshaller="jaxbMarshaller"/>

    <bean id="jaxbMarshaller" class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
        <property name="contextPath" value="com.xml.domain" />
     </bean>

    <int:channel id="outboundChannel"/>

    <int:service-activator id="printing" input-channel="outboundChannel"
                           ref="serviceActivator"/>
    <bean id="serviceActivator" class="com.xml.Dispatcher"/>

But when I run code I get some errors with JAXB Unmarshalling:

JAXB unmarshalling exception; nested exception is javax.xml.bind.UnmarshalException: unexpected element (uri:"http://www.w3.org/2005/Atom", local:"feed"). Expected elements are (none)

I was trying to fix it by myself but I cant find a way how to fix this and what do I need to change here... I would appreciate some help. I tried deleting uri from my xml file but it still gave me the same error.

score 2 · Accepted Answer · answered Dec 01 '20 at 17:39

2

See a namespace option on the @XmlRootElement.

So, probably it must look like this:

@XmlRootElement(name="feed", namespace="http://www.w3.org/2005/Atom")

On the other hand we have already a spring-integration-feed module to do the job you trying to achieve manually: https://docs.spring.io/spring-integration/docs/current/reference/html/feed.html#feed

answered Dec 01 '20 at 17:39

Artem Bilan

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I just want to do it manually to get better practise of it. Adding that namespace to @XmlRootElement didn't help still getting same error – budamab Dec 01 '20 at 17:48
OK. Try to add `namespace` on the `@XmlType`. On the other hand see the JaxB generation tool. So, you just feed it that `http://www.w3.org/2005/Atom` XSD and get POJOs back: https://stackoverflow.com/questions/11463231/how-to-generate-jaxb-classes-from-xsd – Artem Bilan Dec 01 '20 at 17:53

JAXB unmarshalling with xml using spring integration

1 Answers1