如何使用java从xml（DOM）的多级别标签中读取特定元素

问题描述：

我想使用java从xml（DOM）读取多级别标签，样本xml是：

I want to read a multi level tags from xml(DOM) using java and the sample xml is :

<root>
     <subclass>
         <subclass>
             <subclass>
                 <name>test1</name>
                 <address>address1</address>
              </subclass>
               <name>test2</name>
               <address>address2</address>
         </subclass>
         <name>test3</name>
         <address>address3</address>
     </subclass>
 </root>

如何读取< name> test2 < / name>和< address> address2 < / address>从上面的xml？

How to read <name>test2</name> and <address>address2</address> from the above xml?

我给了一个示例代码..但我需要动态地找到值。
当我使用子类标签迭代bu，它提供所有的数据。只是我想知道如何获取特定数据，例如< name> test2 < / name>和< address> address2 < / address>

I have given a sample code .. but i need to find the values dynamically. when i am iterating bu using subclass tag, it's giving all the data. just i want to know how to get the specific data like <name>test2</name> and <address>address2</address> .

以下是我正在阅读上述xml的java代码：

Below is my java code which is reading the above xml:

NodeList fList = firstWordElement
                        .getElementsByTagName("root");
                for (int i = 0; i < fList.getLength(); i++) {
                    Node firstFLNode = fList.item(i);
                    if (firstFLNode.getNodeType() == Node.ELEMENT_NODE) {
                        Element firstWdElement = (Element) firstFLNode;
                        NodeList firstWdList = firstWdElement.getElementsByTagName("innerclass");

                        for (int j = 0; j < firstWdList.getLength(); j++) {

                            Element firstWd1Element = (Element) firstWdList.item(j);

                            if (firstWd1Element.getNodeType() == Node.ELEMENT_NODE) {
                                String InnerName = ParseUtil.getTagValue("name", firstWd1Element);
                                String InnerFormat = ParseUtil.getTagValue("format", firstWd1Element);
                                String InnerDescription = ParseUtil.getTagValue("description", firstWd1Element);

                                NodeList innerClassList = firstWd1Element.getElementsByTagName("subclass");

                                for (int k = 0; k < innerClassList.getLength(); k++) {

                                    Element subClassElement = (Element) innerClassList
                                            .item(k);
                                    if (subClassElement.getNodeType() == Node.ELEMENT_NODE) {
                                        String InnerSubName = ParseUtil.getTagValue("name", subClassElement);
                                        System.out.println("Innername==="+ InnerSubName);
                                        String InnerSubFormat = ParseUtil.getTagValue("format", subClassElement);
                                        System.out.println("Innerformat==="+ InnerSubFormat);
                                        String InnerSubDescription = ParseUtil.getTagValue("description", subClassElement);
                                        System.out.println("Innerdescription==="+ InnerSubDescription);

                                    }
                                }

                            }



                        }
                    }
                }

答

使用XPATH API

Use XPATH APIs

您创建一个XPathFactory：

You create an XPathFactory:

XPathFactory factory = XPathFactory.newInstance();

然后，您可以使用此工厂创建XPath对象：

You then use this factory to create an XPath object:

XPath xpath = factory.newXPath();

XPath对象编译XPath表达式：

The XPath object compiles the XPath expression:

XPathExpression expr = xpath.compile("//book[author='Neal Stephenson']/title/text()");

Object result = expr.evaluate(doc, XPathConstants.NODESET);

然后可以将结果转换为DOM NodeList并循环查找所有标题： / p>

You can then cast the result to a DOM NodeList and iterate through that to find all the titles:

NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
    System.out.println(nodes.item(i).getNodeValue()); 
}

如何使用java从xml（DOM）的多级别标签中读取特定元素

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