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Java：读取包含许多嵌套元素的xml

2 周，3 日 Questions & Answers

我有一个看起来有点类似于以下内容的xml。我需要从属性和标记中获取值并存储它们。但我不明白如何进入2级（3、4等）嵌套元素。我使用了我在互联网上找到的以下代码，它使用了DOM，但我无法获得正确的RegNumber及其属性。提前谢谢

nodeList = xmldocument.getElementsByTagName("Header");      
        if (nodeList != null && nodeList.getLength() > 0) {
            for (int i = 0; i < nodeList.getLength(); i++) {
                //get the header element
                Element header = (Element) nodeList.item(i);
                System.out.println("Element: " + ((Element)nodeList.item(i)).getNodeName());
                System.out.println(header.getAttribute("time"));
            }
        }
        nodeList = xmldocument.getElementsByTagName("Document");      
        if (nodeList != null && nodeList.getLength() > 0) {
            for (int i = 0; i < nodeList.getLength(); i++) {

                //get the document element
                Element document = (Element) nodeList.item(i);
                System.out.println("Element: " + ((Element)nodeList.item(i)).getNodeName());
                System.out.println(document.getAttribute("Id"));

                nodeList = document.getElementsByTagName("RegNumber"); 
                for (int j = 0; j < nodeList.getLength(); j++) {

                    //get the RegNumber element
                    Element regNumber = (Element) nodeList.item(j);
                    System.out.println("Element: " + ((Element)nodeList.item(j)).getNodeName());
                    System.out.println(regNumber.getAttribute("regpoint"));

                }
            }

        }

xml:

<XML xsi:schemaLocation="http://www.codetools.it XSD2.xsd" xmlns="http://www.codetools.it" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <Header time="2001-12-17T09:30:47Z" />
            <Document Id="456">
                <RegNumber regpoint="" regdate="2001-12-17T09:30:47Z">123/456</RegNumber>
                <Confident flag="0"/>
                <DocNumber kind="">
                    <RegNumber RegPoint="" regdate="2001-12-17T09:30:47Z">456/789</RegNumber>
                    <Organization fullname="lol" shortname="" ownership="lol" ogrn="78945612" inn="">
                        <OfficialPerson>
                            <Name  Firstname="John"/>
                            <Official Department="" post=""/>
                            <SignDate>2001-12-17T09:30:47Z</SignDate>
                        </OfficialPerson>
                        <Econtact type="1">test@test.com.ua</Econtact>
                        <Address street="" settlement="" postcode="" postbox="" flat="" district="" region="" country="" nontypical="" house=""/>
                    </Organization>
                </DocNumber>
                <DocTransfer os="Windows" type=".docx" type_ver="" char_set="" description="kkkk">
    </DocTransfer>
            <Reghistory idnumber="">
                <RegNumber RegPoint="" regdate=""/>
                <Organization fullname="" shortname="" ownership="" ogrn="" inn="">
                    <Econtact type=""/>
                    <Address street="" settlement="" postcode="" postbox="" flat="" district="" region="" country="" nontypical="" house=""/>
                </Organization>
            </Reghistory>
            <Author>
                <Organization fullname="" shortname="" ownership="" ogrn="12345678" inn="">
                    <OfficialPerson>
                        <Name  Firstname="" />
                        <Official Department="" post=""/>
                        <SignDate>2011-12-17T09:30:47Z</SignDate>
                    </OfficialPerson>
                    <Econtact type="Рї">smirnov@test.com</Econtact>
                    <Address street=""  postcode="1234" postbox="" flat="" district="" region="" country="" nontypical="" house="12"/>
                </Organization>
                <PrivatePerson>
                    <Name Surname="" Firstname="" Fathername=""/>
                    <Econtact type=""/>
                    <Address street="" settlement="" postcode="" postbox="" flat="" district="" region="" country="" nontypical="" house=""/>
                    <SignDate/>
                    <Rank privilege="" socialposition="" sex=""/>
                </PrivatePerson>
            </Author>
            <Validator attestation="0">
                <DocNumber kind="наказ">
                    <RegNumber RegPoint="" regdate="2001-12-17T09:30:47Z"/>
                    <Organization fullname="" shortname="" ownership="" ogrn="14725836" inn="">
                        <Econtact type="Рї">kmu@test.com</Econtact>
                        <Address street="" settlement="" postcode="" postbox="" flat="" district="" region="" country="" nontypical="" house=""/>
                    </Organization>
                </DocNumber>
                <Organization fullname="" shortname="РљРњРЈ" ownership="" ogrn="96325878" inn="">
                    <Econtact type="String">kmu@test.com</Econtact>
                    <Address street="Пушкіна" settlement="" postcode="4563" postbox="" flat="" district="" region="" country="" nontypical="" house="23"/>
                    <OfficialPerson>
                        <Name Surname="" Firstname="" Fathername=""/>
                        <Official Department="" post=""/>
                        <SignDate>2011-12-17T09:30:47Z</SignDate>
                    </OfficialPerson>
                </Organization>
                <PrivatePerson>
                    <Name Surname="" Firstname="" Fathername=""/>
                    <Econtact type=""></Econtact>
                    <Address street="" settlement="" postcode="" postbox="" flat="" district="" region="" country="" nontypical="" house=""/>
                    <SignDate></SignDate>
                    <Rank privilege="" socialposition="" sex=""/>
                </PrivatePerson>
            </Validator>
            <Addressee>
                <Referred id="" retype="">
                    <RegNumber regdate="" regpoint=""/>
                    <TaskNumber taskDate=""/>
                </Referred>
                <Organization fullname="String" shortname="" ownership="" ogrn="85236974" inn="">
                    <OfficialPerson>
                        <Name Surname="" Firstname="" Fathername=""/>
                        <Official Department="" post=""/>
                    </OfficialPerson>
                    <Econtact type="Рї">sofki@test.com</Econtact>
                    <Address street="" settlement="" postcode="" postbox="" flat="" district="" region="" country="" nontypical="" type="" house=""/>
                </Organization>
                <PrivatePerson>
                    <Name Surname="" Firstname="" Fathername=""/>
                    <Econtact type=""></Econtact>
                    <Address street="" settlement="" postcode="" postbox="" flat="" district="" region="" country="" nontypical="" house=""/>
                    <Rank privilege="" socialposition="" sex=""/>
                </PrivatePerson>
            </Addressee>
            <Writer>
                <Organization fullname="" shortname="" ownership="" ogrn="" inn="">
                    <OfficialPerson>
                        <Name Surname="" Firstname="" Fathername=""/>
                        <Econtact type=""></Econtact>
                    </OfficialPerson>
                </Organization>
                <PrivatePerson>
                    <Name Surname="" Firstname="" Fathername=""/>
                    <Econtact type=""></Econtact>
                </PrivatePerson>
            </Writer>
        </Document>

编辑。按照建议，我试图找出JAXB的东西。xjc工具生成了3个类：ObjectFactory、package info和XML。我发现以下代码用于从xml创建对象：

public static void main(String[] args) {
        try {

            File file = new File("F:\\Untitled3.xml");
            JAXBContext jaxbContext = JAXBContext.newInstance(XML.class);

            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            XML xml = (XML) jaxbUnmarshaller.unmarshal(file);
            System.out.println(xml);

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

这是正确的方法，还是我需要使用ObjectFactory

ObjectFactory f =new ObjectFactory();
            XML xml1 = f.createXML();

如何创建包含所有标记和属性的对象，然后从中创建xml文件？我对java和jaxb还不熟悉，所以请耐心听我说


共 (2) 个答案

  1. # 1 楼答案

    在每个节点上再次使用“getElementsByTagName”函数，以按标记名获取元素。显然

    下面是我的示例代码，深入到几个层次：

    DocumentBuilder db = dbf.newDocumentBuilder();
        Document doc = db.parse(acpFile);
        Element docEle = doc.getDocumentElement();
        NodeList series = docEle.getElementsByTagName("dod:recordSeries");

        if(series != null && series.getLength()>0) 
        {
            for(int i=0; i<series.getLength(); i++) 
            {
                Element serie = (Element)series.item(i);
                System.out.println("S   "+serie.getAttribute("view:childName"));
                NodeList categories = serie.getElementsByTagName("dod:recordCategory");

                for(int j=0; j<categories.getLength(); j++)
                {
                    Element category = (Element)categories.item(j);
                    System.out.println("C    "+category.getAttribute("view:childName"));
                    NodeList recordFolders = category.getElementsByTagName("rma:recordFolder");

                    for(int k=0; k<recordFolders.getLength(); k++)
                    {
                        Element folder = (Element)recordFolders.item(k);
                        System.out.println("F     "+folder.getAttribute("view:childName"));
                    }
                }
            }
        }
  2. # 2 楼答案

    对于允许您在特定深度访问节点的方法，它通常没有意义或通常没有用处。这不仅仅是关于Java，而是关于DOM规范，我相信这是正确的决定

    人们通常通过多种有意义的方式之一访问节点：

    1. 通过标记名，标记名通常表示节点的含义
    2. XPath——文档的完整结构的含义
    3. 绑定，例如JAXB（基本上，您不再处理XML，而是处理java类）
    4. 有旧的SAX（不是DOM）和StAX（DOM和SAX的混合物）

    查找xpath，这将非常有用