java - XML 到 Java 对象

Question

我搜索了与该主题相关的所有问题，但没有找到答案。我正在尝试将 xml 文档转换为 java 对象。在搜索执行相同操作的选项后，我发现 jaxb 是执行相同操作的最佳选择。我引用了很多文章并提出了这个不起作用的解决方案。有人可以帮助我吗？

XML 请求:

<Vectors>
    <Vector>
        <Id>1</Id>
        <Name>abc</Name>
         <Desc>abcdefg</Desc>
         <Type>body</Type>
         <Snippet>
            <![CDATA[<total>1234</total>]]>
         </Snippet>
    </Vector>
    <Vector>
         <Id>2</Id>
         <Name>def</Name>
         <Desc>abcdefghigj</Desc>
         <Type>body</Type>
         <Snippet>
            <![CDATA[<total>12345</total>]]>
         </Snippet>
     </Vector>
</Vectors>

我想创建 2 个 Vector 类的 java 对象。类 Vector 如下所示

    package com.abc.TryXmltoJava;

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

    public class Vector {
        int Id,
        String Name;
        String Desc;
        String Type;

        @XmlElement
        public String getName() {
             return Name;
        }
        public void setName(String name) {
             this.Name = name;
        }

        @XmlElement
        public String getDesc() {
            return Desc;
        }
        public void setDesc(String desc) {
            this.Desc = desc;
        }

        @XmlElement
        public String getType() {
            return Type;
        }
        public void setType(String type) {
            this.Type = type;
        }
}

现在我已经创建了 Vectors 类，它跟踪两个对象并使用列表实用程序创建一个 Vector 对象列表..

 package com.abc.TryXMLtoObject;

 import javax.xml.bind.annotation.*;

 @XmlRootElement(name="Vectors")
 public class Vectors {

 @XmlElement(name="Vector")
     Vector vector;


     public Vector getVector() {
        return vector;
     }

     public void setVector(Vector vector1) {
        this.vector = vector1;
     }
}

我将尝试使用这两个创建 Java 对象列表的类来解码 xml 对象。解码类如下所示..

  package com.abc.TryXMLtoObject;

  import java.io.File;
  import javax.xml.bind.JAXBContext;
  import javax.xml.bind.JAXBException;
  import javax.xml.bind.Unmarshaller;

  public class JAXBExampleUnmarshal {

       public static void main(String[] args) {

         try {

          File file = new File("C:\\file.xml");
          JAXBContext jaxbContext = JAXBContext.newInstance(Vectors.class);

          Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
          Vectors vectors = (Vectors) jaxbUnmarshaller.unmarshal(file);
          System.out.println(vectors);

         } catch (JAXBException e) {
          e.printStackTrace();
         }

   }
 }

运行此代码后..我收到以下错误:

javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"Vectors"). Expected elements are (none)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext$DefaultRootLoader.childElement(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.startElement(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(Unknown Source)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(Unknown Source)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(Unknown Source)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(Unknown Source)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(Unknown Source)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(Unknown Source)
    at com.abc.TryXMLtoObject.JAXBExampleUnmarshal.main(JAXBExampleUnmarshal.java:17)

Answer 1

一开始，你在Vectors你必须有 List<Vector> vectorList , 不是单数 Vector .
此外，来自堆栈跟踪的文本 unexpected element (uri:"", local:"Vkectors")告诉我，在 xml 的某处你有 Vkectors元素，那是错误的。
最后，我强烈建议您将所有注释都放在 get-methods 上，而不是变量上，原因有两个:如果我没记错的话，会发生一些名称冲突，其次，如果您有来自 Hibernate 或类似东西的代理，来自字段的注释将消失，但 get-methods 的注释将保留。