java - 如何在java中使用xpathh读取xml的所有节点？

Question

我有一个 xml 文件，我想读取 xml 所有子节点的值。我的 xml 是

 <branches>
        <branch-area name="abc">
            <branch>
                <branch-name> xyz Street</branch-name>
                <branchID>5689742</branchID>
                <branchAddress>xyz address</branchAddress> 
                <atm>true</atm>
                <branch>true</branch>
                <tab title="Contact">
      <![CDATA[<table>
        <tr>
            <td class="head">Branch</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Address</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Sort Code</td>
            <td>215863</td>
        </tr>
        </table>]]>
    </tab>
            </branch>
        </branch-area>
        <branch-area name="def 11">
            <branch>
                <branch-name>pqr</branch-name>
                <branchID>123456</branchID>
                 <branchAddress>pqr address </branchAddress>
                 <atm>true</atm>
                 <branch>true</branch>
                 <tab title="Contact">
      <![CDATA[<table>
        <tr>
            <td class="head">Branch</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Address</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Sort Code</td>
            <td>215863</td>
        </tr>
        </table>]]>
           </tab>
            </branch>
        </branch-area>
        <branch-area name="ghi 14">
            <branch>
                <branch-name>jkl</branch-name>
                <branchID>589674</branchID>
                <branchAddress>jkl address</branchAddress>
                <atm>true</atm>
                <branch>true</branch>
<tab title="Contact">
      <![CDATA[<table>
        <tr>
            <td class="head">Branch</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Address</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Sort Code</td>
            <td>215863</td>
        </tr>
        </table>]]>
    </tab>
            </branch>
        </branch-area>
    </branches>

我正在使用这个 xpath 表达式来获取特定的分支。

String  xpathExpression = "/branches/branch-area[name='abc']/branch";

它返回给我特定的分支，即

    <branch>
                    <branch-name> xyz Street</branch-name>
                    <branchID>5689742</branchID>
                    <branchAddress>xyz address</branchAddress> 
                    <atm>true</atm>
                    <branch>true</branch>
<tab title="Contact">
      <![CDATA[<table>
        <tr>
            <td class="head">Branch</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Address</td>
            <td>bandra Street</td>
        </tr>
        <tr>
            <td class="head">Sort Code</td>
            <td>215863</td>
        </tr>
        </table>]]>
    </tab>
                </branch>

但我想获取其子节点的值，例如分支名称branchID等，为此我是否需要为每个子节点使用另一个xpath表达式，或者还有其他方法吗？如果是，请指导我

Answer 1

你可以...

使用像 /branches/branch-area[@name='abc']/branch/* 这样的路径，它将返回所有子节点的 NodeList包含在分支中。

XPath xpath = XPathFactory.newInstance().newXPath();
XPathExpression branchExp = xpath.compile("/branches/branch-area[@name='abc']/branch/*");
NodeList branchNodes = (NodeList) branchExp.evaluate(dom, XPathConstants.NODESET);
System.out.println(branchNodes.getLength());
for (int index = 0; index < branchNodes.getLength(); index++) {
    Node node = branchNodes.item(index);
    System.out.println(node.getTextContent());
}

输出类似...

5
 xyz Street
5689742
xyz address
true

你可以...

使用 branch 节点作为搜索的父节点来搜索每个单独的子节点...

XPath xpath = XPathFactory.newInstance().newXPath();
XPathExpression branchExp = xpath.compile("/branches/branch-area[@name='abc']/branch");
Node branchNode = (Node) branchExp.evaluate(dom, XPathConstants.NODE);

XPathExpression nameExp = xpath.compile("branch-name/text()");
String name = (String) nameExp.evaluate(branchNode, XPathConstants.STRING);
System.out.println("Name = " + name);

输出类似...

Name =  xyz Street

已更新...

因此，CDATA 不会被 xPath 处理，而是需要获取 tab 节点的文本，并将其解析为 Document 并在其上运行 xPath，例如...

try {
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder();
    Document dom = db.parse(new File("Test.xml"));
    XPath xpath = XPathFactory.newInstance().newXPath();

    // Find the "thing" node...
    XPathExpression thingExpr = xpath.compile("/branches/branch-area/branch/tab");
    Node things = (Node) thingExpr.evaluate(dom, XPathConstants.NODE);
    String table = things.getTextContent();

    ByteArrayInputStream bais = new ByteArrayInputStream(table.getBytes());
    Document tblDom = db.parse(bais);
    XPathExpression tableExp = xpath.compile("/table/tr[td[text()='Sort Code']]/td[not(@*)]");
    NodeList nodes = (NodeList) tableExp.evaluate(tblDom, XPathConstants.NODESET);
    System.out.println(nodes.getLength());
    for (int index = 0; index < nodes.getLength(); index++) {
        Node node = nodes.item(index);
        System.out.println(node.getTextContent());
    }
} catch (Exception exp) {
    exp.printStackTrace();
}