使用java中的Jackson XmlMapper将XML文件转换（反序列化）转换为Bean（POJO）

Question

我想使用jackson rapid xml的XMLMapper解析一个XML文件并转换为pojo类。我完成了这项工作，但最后我遇到了问题。

Xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:atom="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/" version="2.0">
   <channel>
      <title>1st Title</title>
      <link>http://www.eample.com</link>
      <language>en-US</language>
      <pubDate>Thu, 16 Jun 2016 04:37:53 +0000</pubDate>
     <item>
         <title>The DI Wire’s QA With CNL CEO Tom Sittema</title>
         <link>http://www.eample.com</link>
         <description>5 lines description</description>
         <pubDate>Wed, 15 Jun 2016 16:30:07 +0000</pubDate>
    </item>
    <item>
        <title>2nd title</title>
        <link>http://www.globest.com/sites/paulbubny/2016/06</link>
        <description>5 lines description</description>
        <pubDate>Wed, 15 Jun 2016 16:28:40 +0000</pubDate>
    </item>
 </channel>
 </rss>

我只想要Item标签包含。但问题是我只得到第二个项目标签包含。

Rss.java :

@JacksonXmlRootElement(localName = "rss")
public class Rss {

private String version;
private Channel channel;

   //setters & getters
}

Channel.java :

public class Channel {

private String title;
private String link;
private String description;
private String language;
private String lastBuildDate;
private String pubDate;
private String atom;
private String generator;
private String href;
private String rel;
private String type;

@XmlElement(name = "item")
@XmlElementWrapper(name = "wrapitem")
private List<Item> item;

    //Setters & getters
}

Item.java :

public class Item {

private String title;
private URL link;
private String description;
private String pubDate;
private String category;
private String source;
private String guid;
private String isPermaLink;
private String url;

    //setter & getters
}

Main.java :

  public class MainClass {

  public static void main(String[] args) {
    try {
        JacksonXmlModule module = new JacksonXmlModule();
        module.setDefaultUseWrapper(false);
        XmlMapper xmlMapper = new xmlMapper(module);                                                                        Rss rss = xmlMapper.readValue(new File("/home/Address.xml"), Rss.class);
        Channel channel = rss.getChannel();
        System.out.println(channel);
        List<Item> item = channel.getItem();
        System.out.println(item);
        if (item != null) {
            for (Item a : item) {
                System.out.println(a.getTitle());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
   }
}

输出：

 2nd Title
 null

请帮助我确定为什么它会输出这样的输出，首先必须打印第一个标题然后打印第二个标题，而不是为什么这个代码会给出这样的输出。

先谢谢。