如何将字符串转换为xml以便在createUnmarshaller中使用以转换为pojo实体

Question

我想将字符串转换为xml，然后使用createUnmarshaller方法转换为pojo实体。

的xmlString：

 <File>
     <code>63213713</code>
     <name>textsss</name>
     <player>GAMMER</player>
     <system>SS</system>
  <File>

My Method将String转换为Xml：

    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    Source src = null;
    DocumentBuilder builder;
    try {
        builder = factory.newDocumentBuilder();

        // Use String reader
        Document document = builder.parse( new InputSource(new StringReader( xmlString ) ) );


        src = new DOMSource( document );
        FileWriter writer = new FileWriter(new File("./src/main/folder/xmlFile.xml"));
        StreamResult result = new StreamResult(writer);
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        transformer.transform(src, result);

我有方法Marshaller：

  JAXBContext context = JAXBContext.newInstance("br.com.Test.domain");
    Marshaller m = context.createMarshaller();
    Unmarshaller um = context.createUnmarshaller();
    Object obj = um.unmarshal();

如何将String转换为xml并使用此方法Marshaller？我不明白如何为方法unmarshaller传递方法转换的结果。 我应该通过什么样的方式？来源？