Apache camel xml反序列化失败

Question

我正在尝试使用apache camel jackson xml对xml进行反序列化，然后发生了一些奇怪的事情，我无法解释。这是我正在尝试反序列化的xml（它是简单的xmltd v xml文件）：

<?xml version="1.0" encoding="UTF-8"?>
<tv>
  <programme start="20210102000300 +0000" stop="20210102003000 +0000" channel="XTV100005403" recordable="Y" npvrenable="Y" id="SH032096260000.20210102000300.44345" type="program">
     <title lang="en">Barbados Ninja Throwdown</title>
     <desc lang="en">Contestants compete to complete a challenging obstacle course the fastest.</desc>
     <credits>
        <actor nameId="1288485">Wayne Simmons</actor>
     </credits>
     <date>20190427</date>
     <category>Reality</category>
     <category>Action sports</category>
     <category>Action</category>
     <category>Adventure</category>
     <releaseType>TV</releaseType>
     <extentionInfo>
        <key>releaseStatus</key>
        <value>1</value>
     </extentionInfo>
  </programme>
</tv>

这是我的POJO：

电视。Java语言

@XmlRootElement(name = "tv")
@JsonIgnoreProperties(ignoreUnknown = true)
@Data
public class Tv {

  @XmlElement(name = "programme")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Programme> programmes = new ArrayList<>();

}

程序Java语言

@JsonIgnoreProperties(ignoreUnknown = true)
@Data
public class Programme {

  @XmlAttribute(name = "id")
  @XmlJavaTypeAdapter(NormalizedStringAdapter.class)
  private String id;

  @XmlAttribute(name = "type")
  @XmlJavaTypeAdapter(NormalizedStringAdapter.class)
  private String type;

  @XmlAttribute(name = "start", required = true)
  @JsonDeserialize(using = OffsetDateTimeDeserializer.class)
  private OffsetDateTime start;

  @XmlAttribute(name = "stop")
  @JsonDeserialize(using = OffsetDateTimeDeserializer.class)
  private OffsetDateTime stop;

  @XmlAttribute(name = "pdc-start")
  @JsonDeserialize(using = OffsetDateTimeDeserializer.class)
  private OffsetDateTime pdcStart;

  @XmlAttribute(name = "vps-start")
  @JsonDeserialize(using = OffsetDateTimeDeserializer.class)
  private OffsetDateTime vpsStart;

  @XmlAttribute(name = "showview")
  @XmlJavaTypeAdapter(NormalizedStringAdapter.class)
  private String showview;

  @XmlAttribute(name = "videoplus")
  @XmlJavaTypeAdapter(NormalizedStringAdapter.class)
  private String videoplus;

  @XmlAttribute(name = "channel", required = true)
  @XmlJavaTypeAdapter(NormalizedStringAdapter.class)
  private String channel;

  @XmlAttribute(name = "clumpidx")
  @XmlJavaTypeAdapter(NormalizedStringAdapter.class)
  private String clumpidx;

  @XmlElement(name = "title", required = true)
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Label> titles;

  @XmlElement(name = "sub-title")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Label> subTitle;

  @XmlElement(name = "desc")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Label> descriptions;

  @XmlElement(name = "credits")
  private Credits credits;

  private String date;

  @XmlElement(name = "category")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Label> categories;

  @XmlElement(name = "keyword")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Label> keywords;

  private Label language;

  @XmlElement(name = "orig-language")
  private Label origLanguage;

  private Length length;

  @XmlElement(name="icons")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Icon> icons;

  @XmlElement(name = "url")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> urls;

  @XmlElement(name = "country")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Label> countries;

  @XmlElement(name = "episode-num")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<EpisodeNum> episodeNumbers;

  private Video video;

  private Audio audio;

  @XmlElement(name = "previously-shown")
  private PreviouslyShown previouslyShown;

  private Label premiere;

  @XmlElement(name = "last-chance")
  private Label lastChance;

  @XmlElement(name = "new")
  private Label isNew;

  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Subtitles> subtitles;

  @XmlElement(name = "rating")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Rating> ratings;

  @XmlElement(name = "star-rating")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<StarRating> starRatings;

  @XmlElement(name = "review")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<Review> reviews;
  
}

Credits.java

@Data
public class Credits {
  @XmlElement(name = "director")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> directors;

  @XmlElement(name = "actor")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> actors;

  @XmlElement(name = "writer")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> writers;

  @XmlElement(name = "adapter")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> adapters;

  @XmlElement(name = "producer")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> producers;

  @XmlElement(name = "composer")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> composers;

  @XmlElement(name = "editor")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> editors;

  @XmlElement(name = "presenter")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> presenters;

  @XmlElement(name = "commentator")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> commentators;

  @XmlElement(name = "guest")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> guests;
}

其他POJO并不重要。下面是路由配置：

@Override
  public void configure() throws Exception {
    final JacksonXMLDataFormat dataFormat = new JacksonXMLDataFormat();
    dataFormat.setUnmarshalType(Tv.class);

    from("file:///someLocation")
        .routeId(getClass().getSimpleName())
        .autoStartup(true)
        .unmarshal(dataFormat)
        .process("someProcessorBean")

  }

使用此设置和我在开始时提供的xml，会发生以下异常：

通用域名格式。fasterxml。杰克逊。数据绑定。exc.MismatchedInputException：无法构造程序的实例（尽管至少存在一个创建者）：在[源：（BufferedInputStream）；行：9，列：20]（通过引用链：com.azdio.mdw.ingest.epg.xmltv.common.domain.Tv[“Program”]处，没有可从字符串值（'20190427'）反序列化的字符串参数构造函数/工厂方法-

我花了很多时间才明白这意味着什么。因此，它似乎接受结束标记作为标记的结束，然后它尝试用标记值创建一个新的程序实例，但失败了，因为它不知道如何做。为了证明我自己，我将标记移到了标记的末尾，因此xml如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<tv>
  <programme start="20210102000300 +0000" stop="20210102003000 +0000" channel="XTV100005403" recordable="Y" npvrenable="Y" id="SH032096260000.20210102000300.44345" type="program">
     <title lang="en">Barbados Ninja Throwdown</title>
     <desc lang="en">Contestants compete to complete a challenging obstacle course the fastest.</desc>
     <date>20190427</date>
     <category>Reality</category>
     <category>Action sports</category>
     <category>Action</category>
     <category>Adventure</category>
     <releaseType>TV</releaseType>
     <extentionInfo>
        <key>releaseStatus</key>
        <value>1</value>
     </extentionInfo>
     <credits>
        <actor nameId="1288485">Wayne Simmons</actor>
     </credits>
  </programme>
</tv>

这次当我运行应用程序时，xml被正确地反序列化，没有任何异常。有人能解释一下为什么会这样，我在什么地方犯了错吗？

我使用的是apache camel 2.25.3和camel-jacksonxml的相同版本。

编辑：

我成功地向jackson指出了这个问题：

 JacksonXmlModule jacksonXmlModule = new JacksonXmlModule();
 jacksonXmlModule.setDefaultUseWrapper(false);
 ObjectMapper objectMapper = new XmlMapper(jacksonXmlModule);
 objectMapper.registerModule(new JaxbAnnotationModule());
 objectMapper.readValue(new File("xmlFilePath"), Tv.class);

这导致了同样的例外。

Answer 1

所以我找到了导致这个异常的原因，尽管我不完全确定为什么会这样。在对jackson的对象映射器进行调试之后，我发现问题出在actor标记的nameId属性中。当我有以下情况时，反序列化程序似乎无法决定如何执行：

  @XmlElement(name = "actor")
  @JacksonXmlElementWrapper(useWrapping = false)
  private List<String> actors;

所以我发现的一个解决方案（我不确定这是最正确的）是创建另一个pojo CreditsElement.java：

@Data
@JsonIgnoreProperties(ignoreUnknown = true)
public class CreditsElement {

  @XmlValue
  private String value;
}

我不包括nameId属性，因为我不需要它。除了这个解决方案之外，还有没有更好的方法来映射它，而无需创建另一个类并使用List属性？