How to annotate a list using @XmlElement?

Question

I have the following annotation using javax.xml.bind.annotation.XmlElement:

@XmlElement         
public List getKeywords() {
    r         


        

Answer 1

Above answer by - Blaise Doughan is completely correct

Another simple way is , even if you don't write the - @XmlElementWrapper

 private List<String> keywords;

 @XmlElementWrapper
    @XmlElement(name="keyword")
    public List<String> getKeywords() {
        return keywords;
    }

You can use it this way - write the XmlAccessorType on Class level , then XML element name will be same as the class member name - keywords

import java.util.List;
import javax.xml.bind.annotation.*;

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Content {

    private List<String> keywords;

    public Content() {}


    public List<String> getKeywords() {
        return keywords;
    }

    public void setKeywords(List<String> keywords) {
        this.keywords = keywords;
    }  

}

Answer 2

Use this form:

@XmlElementWrapper(name="keywords")
@XmlElement(name="keyword")

Please note that if keywords is empty then you will get <keywords />.

Sometimes you will need to add @XmlRootElement to your class (depends on the context) and the @XmlAccessorType(XmlAccessType.?) annotation. I usually use @XmlAccessorType(XmlAccessType.FIELD) and annotate my fields with @XmlElement.

Answer 3

You need to leverage @XmlElementWrapper and @XmlElement.

Java Model

Content

import java.util.List;
import javax.xml.bind.annotation.*;

@XmlRootElement
public class Content {

    private List<String> keywords;

    public Content() {}

    @XmlElementWrapper
    @XmlElement(name="keyword")
    public List<String> getKeywords() {
        return keywords;
    }

    public void setKeywords(List<String> keywords) {
        this.keywords = keywords;
    }  

}

Demo Code

Demo

import java.util.*;
import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Content.class);

        List<String> strings = new ArrayList<String>(2);
        strings.add("foo");
        strings.add("bar");

        Content content = new Content();
        content.setKeywords(strings);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(content, System.out);
    }

}

Output

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<content>
    <keywords>
        <keyword>foo</keyword>
        <keyword>bar</keyword>
    </keywords>
</content>

For More Information

Below are links to a couple articles from my blog that provide additional information:

• http://blog.bdoughan.com/2010/09/jaxb-collection-properties.html
• http://blog.bdoughan.com/2012/12/jaxb-representing-null-and-empty.html