如何在JAXB中封送具有不同值的多组对象？

Question

我正在尝试封送标记不断变化的标记。 编组时，我会继续覆盖对象值，并最终获得与标签相同的值。

所需的输出：

<bookshelf>
  <shelfnumber> 001 </shelfnumber>
  <shelfowner> John Snow </shelfowner>
     <book>
        <Author>Ned Stark</Author>
        <Chapters>24</Chapters>
               <Chapter1>.......</Chapter1>
               <Chapter2>.......</Chapter2>
     </book>
     <book>

        <Author>Rob Stark</Author>
        <Chapters>24</Chapters>
               <Chapter1>.......</Chapter1>
               <Chapter2>.......</Chapter2>
     </book>
     <magazine>
        <Author>Tyrion Lannister</Author>
        <Pages>24</Pages>
               <Page1>.......</Page1>
               <Page2>.......</Page2>
     </magazine>    
</bookshelf>

我有一个switch语句在遍历包含从数据库中提取的值的arraylist时创建对象。 我最终覆盖了最后一个对象，因此我正在寻找一种方法来保存在迭代器的每个遍历中填充的一组对象。

public class TagFactory {
/*
 * Creates an arraylist from which to read the values and populate the tags
 */
private ArrayList<Data> Values;

public TagFactory(ArrayList<Data> values) {
    Values = values;

}

/*
 * Populates the Tran tags for the output based on the values in the Vales
 * arraylist. Uses the index of each cell to match up with the corresponding
 * tags
 */
public Tran TagPopulator() {

    BookShelf bookshelf = new BookShelf();
    Magazine mag = new Magazine();
    Book book = new book();
    Page page = new Page();
    Chapter chapter = new Chapter();


    /*
     * Create iterator and iterate though the extracted data arraylist
     */

    /*
     * Static Fields constructors
     */
    bookshelf.setNumber(BigInteger.valueOf(6));
    bookshelf.setAuthor("John Snow");
    ...

    Iterator<Data> ValuesIt = Values.iterator();

    boolean Endofchapter = false;
    boolean Endofpage = false;

    while (ValuesIt.hasNext()) {

        /*
         * Data object to hold the values
         */
        Data data = ValuesIt.next();

        /*
         * Select the appropriate class object constructor based on the
         * index of the cell This index was previously matched up in
         * HeaderValues and is used for a reference Type modification was
         * done for each of the constructor's requirements.
         */


        switch (data.getcellIndex()) {

        // Book->Author
        case 0:
            book.setAuthor(data.getcellValue());

            break;

        // Book->Chapter-> Chap #
        case 1:
            Chapter.add(data.getcellValue());
            ...
            Endofchapter = true;

            break;

        // Mag -> Author
        case 2:
            mag.setAuthor(data.getcellValue());
            break;

        // Mag->Page->Page#
        case 3:
            /*
             * Page object created and modified
             */
            page.setnum(data.getcellValue());

            Endofpage = true;
            break;

        ...
    if(Endofpage){
        mag.add(page);
    }
    if(Endofchapter){
        book.add(chapter);
    }
    bookshelf.add(mag);
    bookshelf.add(book)
...

循环完成后，我正在编组。

添加了封送处理功能

 public class XMLWriter {

    private String FileOutput;
    private Tran Transaction;
    ...

    public void FileOut () {
        try {
            /*
             * Marshal the classes into and XML output
             */
             File file = new File(FileOutput);
             JAXBContext JC = JAXBContext.newInstance(Tran.class);
             Marshaller JCMarshaller = JC.createMarshaller();

             JCMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

             JCMarshaller.marshal(Transaction, file);
             JCMarshaller.marshal(Transaction, System.out);

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

将调用添加到用于编写XML的类。

XMLWriter output = new XMLWriter(outputFilename, newBookshelf.TagPopulator());
    output.FileOut();

除XMLWriter和TagFactory之外的所有对象均由JAXB通过模式生成。

Answer 1

由于我们没有显示XML模式，因此下面的代码可能不完全适合。 但是，它确实会根据XML示例生成有效的XML。 列表由扫描仪代替，从文本文件读取。 您对while / switch的意图对我不太清楚。 我无法想象最后的这些add（）调用可能如何正常工作。

请注意，在将DOM树中的元素插入其父级之前，无需完成表示该元素的对象。 要重复添加，请保留对最新/当前书籍或杂志的引用。

可能还有另一种方法来确定章节和页面的数量。 我完全不知道在章节或页面中应该发生什么。

    BookShelf bookshelf = new BookShelf();
    bookshelf.setShelfnumber( "001" );
    bookshelf.setShelfowner( "John Doe" );

    File f = new File( "data.txt" );
    Scanner scanner = new Scanner( f );
    Book book = null;
    Magazine magazine = null;
    int chapters = 0;
    int pages = 0;
    while( scanner.hasNext() ){
        int cellid = scanner.nextInt();
        switch(cellid){
        case 0:
            book = new Book();
            bookshelf.getBookOrMagazine().add( book );
            book.setAuthor( scanner.nextLine() );
            chapters = 0;
            break;
        case 1:
            Chapter chapter = new Chapter();
            book.getChapter().add( chapter );
            chapter.setNumber( scanner.nextInt() );
            book.setChapters( ++chapters );
            break;
        case 2:
            magazine = new Magazine();
            bookshelf.getBookOrMagazine().add( magazine );
            magazine.setAuthor( scanner.nextLine() );
            pages = 0;
            break;
        case 3:
            Page page = new Page();
            magazine.getPage().add( page );
            page.setNumber( scanner.nextInt() );
            magazine.setPages( ++pages );
            break;
        }
    }

我使用的XML模式文件：

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
       xmlns:jaxb="http://java.sun.com/xml/ns/jaxb"
        version="2.0">
<xs:element name="bookshelf" type="BookShelf"/>
<xs:complexType name="BookShelf">
  <xs:sequence>
    <xs:element name="shelfnumber" type="xs:string"/>
    <xs:element name="shelfowner"  type="xs:string"/>
    <xs:choice maxOccurs="unbounded">
      <xs:element name="book"     type="Book"/>
      <xs:element name="magazine" type="Magazine"/>
    </xs:choice>
  </xs:sequence>
</xs:complexType>
<xs:complexType name="Book">
  <xs:sequence>
    <xs:element name="Author"   type="xs:string"/>
    <xs:element name="Chapters" type="xs:int"/>
    <xs:element name="chapter"  type="Chapter" maxOccurs="unbounded"/>
  </xs:sequence>
</xs:complexType>
<xs:complexType name="Magazine">
  <xs:sequence>
    <xs:element name="Author" type="xs:string"/>
    <xs:element name="Pages"  type="xs:int"/>
    <xs:element name="page"   type="Page" maxOccurs="unbounded"/>
  </xs:sequence>
</xs:complexType>
<xs:complexType name="Chapter">
  <xs:sequence>
    <xs:element name="number" type="xs:int"/>
  </xs:sequence>
</xs:complexType>
<xs:complexType name="Page">
  <xs:sequence>
    <xs:element name="number" type="xs:int"/>
  </xs:sequence>
</xs:complexType>
</xs:schema>