Java : Node (XML) 示例

Node (Java SE 22 & JDK 22) 示例。
您将在大多数 Node 方法中找到代码示例。

注解 :

本文可能使用了翻译软件以方便阅读。另请查看英文原文。

简介

Node 接口是整个文档对象模型的主要数据类型。它表示文档树中的单个节点。 (机器翻译)

Class diagram

Code examples on this page use the printDocument method below.

public void printDocument(Document document) throws TransformerException {
    final var transformer = TransformerFactory.newInstance().newTransformer();
    transformer.setOutputProperty(OutputKeys.INDENT, "yes");
    transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");

    final var result = new StreamResult(new StringWriter());
    transformer.transform(new DOMSource(document), result);

    System.out.print(result.getWriter());
}

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.newDocument();

final var root = document.createElement("root");
System.out.println(root); // [root: null]

document.appendChild(root);

final var child = document.createElement("child");
System.out.println(child); // [child: null]

root.appendChild(child);

final var text = document.createTextNode("abcd");
System.out.println(text); // [#text: abcd]

child.appendChild(text);

//<root>
//    <child>abcd</child>
//</root>
printDocument(document);

Fields

static final short ATTRIBUTE_NODE

该节点是一个 Attr。 (机器翻译)

final var xml = """
        <root attr="abc"/>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node attr = document.getDocumentElement().getAttributes().getNamedItem("attr");
System.out.println(attr); // attr="abc"

System.out.println(Node.ATTRIBUTE_NODE); // 2
System.out.println(attr.getNodeType() == Node.ATTRIBUTE_NODE); // true

static final short CDATA_SECTION_NODE

该节点是一个 CDATASection。 (机器翻译)

final var xml = """
        <root><![CDATA[<&>]]></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node cdata = document.getDocumentElement().getFirstChild();
System.out.println(cdata); // [#cdata-section: <&>]

System.out.println(Node.CDATA_SECTION_NODE); // 4
System.out.println(cdata.getNodeType() == Node.CDATA_SECTION_NODE); // true

static final short COMMENT_NODE

该节点是一个评论。 (机器翻译)

final var xml = """
        <root><!-- abc --></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node comment = document.getDocumentElement().getFirstChild();
System.out.println(comment); // [#comment:  abc ]

System.out.println(Node.COMMENT_NODE); // 8
System.out.println(comment.getNodeType() == Node.COMMENT_NODE); // true

static final short DOCUMENT_FRAGMENT_NODE

该节点是一个 DocumentFragment。 (机器翻译)

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.newDocument();

final Node fragment = document.createDocumentFragment();
System.out.println(fragment); // [#document-fragment: null]

System.out.println(Node.DOCUMENT_FRAGMENT_NODE); // 11
System.out.println(fragment.getNodeType() == Node.DOCUMENT_FRAGMENT_NODE); // true

static final short DOCUMENT_NODE

该节点是一个文档。 (机器翻译)

final var xml = """
        <root/>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final Node document = builder.parse(new ByteArrayInputStream(xml.getBytes()));
System.out.println(document); // [#document: null]

System.out.println(Node.DOCUMENT_NODE); // 9
System.out.println(document.getNodeType() == Node.DOCUMENT_NODE); // true

static final short DOCUMENT_POSITION_CONTAINED_BY

该节点包含在引用节点中。 (机器翻译)

final var xml = """
        <root><child/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final var root = document.getDocumentElement();
System.out.println(root); // [root: null]

final var child = root.getFirstChild();
System.out.println(child); // [child: null]

final var type = root.compareDocumentPosition(child);

System.out.printf("%#x%n", type); // 0x14
System.out.printf("%#x%n", Node.DOCUMENT_POSITION_CONTAINED_BY); // 0x10
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_CONTAINED_BY); // 0x10

static final short DOCUMENT_POSITION_CONTAINS

该节点包含参考节点。 (机器翻译)

final var xml = """
        <root><child/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final var root = document.getDocumentElement();
System.out.println(root); // [root: null]

final var child = root.getFirstChild();
System.out.println(child); // [child: null]

final var type = child.compareDocumentPosition(root);

System.out.printf("%#x%n", type); // 0xa
System.out.printf("%#x%n", Node.DOCUMENT_POSITION_CONTAINS); // 0x8
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_CONTAINS); // 0x8

static final short DOCUMENT_POSITION_DISCONNECTED

两个节点已断开连接。 (机器翻译)

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();

final var document1 = builder.newDocument();
final var node1 = document1.createTextNode("abcd");
System.out.println(node1); // [#text: abcd]

final var document2 = builder.newDocument();
final var node2 = document2.createTextNode("xyz");
System.out.println(node2); // [#text: xyz]

final var type = node1.compareDocumentPosition(node2);

System.out.printf("%#x%n", type); // 0x23
System.out.printf("%#x%n", Node.DOCUMENT_POSITION_DISCONNECTED); // 0x1
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_DISCONNECTED); // 0x1

static final short DOCUMENT_POSITION_FOLLOWING

该节点跟随参考节点。 (机器翻译)

final var xml = """
        <root>
            <child-a/>
            <child-b/>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final var childA = document.getElementsByTagName("child-a").item(0);
System.out.println(childA); // [child-a: null]

final var childB = document.getElementsByTagName("child-b").item(0);
System.out.println(childB); // [child-b: null]

final var type = childA.compareDocumentPosition(childB);

System.out.printf("%#x%n", type); // 0x4
System.out.printf("%#x%n", Node.DOCUMENT_POSITION_FOLLOWING); // 0x4
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_FOLLOWING); // 0x4

static final short DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC

确定在前还是在后取决于具体实施。 (机器翻译)

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();

final var document1 = builder.newDocument();
final var node1 = document1.createTextNode("abcd");
System.out.println(node1); // [#text: abcd]

final var document2 = builder.newDocument();
final var node2 = document2.createTextNode("xyz");
System.out.println(node2); // [#text: xyz]

final short type = node1.compareDocumentPosition(node2);

System.out.printf("%#x%n", type); // 0x23
System.out.printf("%#x%n", Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC); // 0x20
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC); // 0x20

static final short DOCUMENT_POSITION_PRECEDING

第二个节点位于参考节点之前。 (机器翻译)

final var xml = """
        <root>
            <child-a/>
            <child-b/>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final var childA = document.getElementsByTagName("child-a").item(0);
System.out.println(childA); // [child-a: null]

final var childB = document.getElementsByTagName("child-b").item(0);
System.out.println(childB); // [child-b: null]

final var type = childB.compareDocumentPosition(childA);

System.out.printf("%#x%n", type); // 0x2
System.out.printf("%#x%n", Node.DOCUMENT_POSITION_PRECEDING); // 0x2
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_PRECEDING); // 0x2

static final short DOCUMENT_TYPE_NODE

该节点是一个 DocumentType。 (机器翻译)

final var xml = """
        <!DOCTYPE root>
        <root/>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node doctype = document.getDoctype();
System.out.println(doctype); // [root: null]

System.out.println(Node.DOCUMENT_TYPE_NODE); // 10
System.out.println(doctype.getNodeType() == Node.DOCUMENT_TYPE_NODE); // true

static final short ELEMENT_NODE

该节点是一个元素。 (机器翻译)

final var xml = """
        <root/>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node element = document.getDocumentElement();
System.out.println(element); // [root: null]

System.out.println(Node.ELEMENT_NODE); // 1
System.out.println(element.getNodeType() == Node.ELEMENT_NODE); // true

static final short ENTITY_NODE

该节点是一个实体。 (机器翻译)

final var xml = """
        <!DOCTYPE root [
            <!ENTITY aaa "bbb">
        ]>
        <root>&aaa;</root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node entity = document.getDoctype().getEntities().item(0);
System.out.println(entity); // [aaa: null]

System.out.println(Node.ENTITY_NODE); // 6
System.out.println(entity.getNodeType() == Node.ENTITY_NODE); // true

//<root>bbb</root>
printDocument(document);

static final short ENTITY_REFERENCE_NODE

该节点是一个 EntityReference。 (机器翻译)

final var xml = """
        <!DOCTYPE root [
            <!ENTITY aaa "bbb">
        ]>
        <root>&aaa;</root>
        """;

final var factory = DocumentBuilderFactory.newInstance();
factory.setExpandEntityReferences(false);

final var document = factory.newDocumentBuilder().parse(
        new ByteArrayInputStream(xml.getBytes()));

final Node entityReference = document.getDocumentElement().getFirstChild();
System.out.println(entityReference); // [aaa: null]

System.out.println(Node.ENTITY_REFERENCE_NODE); // 5
System.out.println(entityReference.getNodeType() == Node.ENTITY_REFERENCE_NODE); // true

static final short NOTATION_NODE

节点是一种符号。 (机器翻译)

final var xml = """
        <!DOCTYPE root [
           <!NOTATION sample SYSTEM "aaa">
        ]>
        <root/>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node notation = document.getDoctype().getNotations().item(0);
System.out.println(notation); // [sample: null]

System.out.println(Node.NOTATION_NODE); // 12
System.out.println(notation.getNodeType() == Node.NOTATION_NODE); // true

static final short PROCESSING_INSTRUCTION_NODE

该节点是一个 ProcessingInstruction。 (机器翻译)

final var xml = """
        <root><?target content?></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node pi = document.getDocumentElement().getFirstChild();
System.out.println(pi); // [target: content]

System.out.println(Node.PROCESSING_INSTRUCTION_NODE); // 7
System.out.println(pi.getNodeType() == Node.PROCESSING_INSTRUCTION_NODE); // true

static final short TEXT_NODE

该节点是一个文本节点。 (机器翻译)

final var xml = """
        <root>abcd</root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node text = document.getDocumentElement().getFirstChild();
System.out.println(text); // [#text: abcd]

System.out.println(Node.TEXT_NODE); // 3
System.out.println(text.getNodeType() == Node.TEXT_NODE); // true

Methods

Node appendChild (Node newChild)

将节点 newChild 添加到此节点的子节点列表的末尾。 (机器翻译)

final var xml = """
        <root/>
        """;

final var document = DocumentBuilderFactory.newInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node child = document.createElement("child");
System.out.println(child); // [child: null]

final Node ret = root.appendChild(child);
System.out.println(ret); // [child: null]

//<root>
//    <child/>
//</root>
printDocument(document);

Node cloneNode (boolean deep)

返回此节点的副本，即作为节点的通用复制构造函数。 (机器翻译)

final var xml = """
        <root><a><b>xyz</b></a></root>
        """;

final var document = DocumentBuilderFactory.newInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <a>
//        <b>xyz</b>
//    </a>
//</root>
printDocument(document);

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node childA = document.getElementsByTagName("a").item(0);
System.out.println(childA); // [a: null]

final Node clonedDeepNode = childA.cloneNode(true);
final Node clonedNode = childA.cloneNode(false);

root.appendChild(clonedDeepNode);
root.appendChild(clonedNode);

//<root>
//    <a>
//        <b>xyz</b>
//    </a>
//    <a>
//        <b>xyz</b>
//    </a>
//    <a/>
//</root>
printDocument(document);

short compareDocumentPosition (Node other)

将参考节点（即调用此方法的节点）与节点（即作为参数传递的节点）进行比较，比较它们在文档中的位置和文档顺序。 (机器翻译)

final var xml = """
        <root>
            <child/>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]

final short type = root.compareDocumentPosition(child);
System.out.printf("%#x%n", type); // 0x14

System.out.printf("%#x%n", Node.DOCUMENT_POSITION_CONTAINED_BY); // 0x10
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_CONTAINED_BY); // 0x10

System.out.printf("%#x%n", Node.DOCUMENT_POSITION_FOLLOWING); // 0x4
System.out.printf("%#x%n", type & Node.DOCUMENT_POSITION_FOLLOWING); // 0x4

NamedNodeMap getAttributes ()

包含此节点的属性的 NamedNodeMap（如果它是一个元素）或否则为 null。 (机器翻译)

final var xml = """
        <root>
            <child aa="AA" bb="BB" />
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]

final var attributes = child.getAttributes();

System.out.println("-- attributes --");
for (int i = 0; i < attributes.getLength(); i++) {
    final var attr = attributes.item(i);
    System.out.println(attr);
}

// Result
// ↓
//-- attributes --
//aa="AA"
//bb="BB"

String getBaseURI ()

此节点的绝对基 URI；如果实现无法获取绝对 URI，则为 null。 (机器翻译)

final var path = Path.of("R:", "java-work", "a.xml");
System.out.println(path); // R:\java-work\a.xml

Files.writeString(path, """
        <root>
            <child/>
        </root>
        """);

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(path.toFile());

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]
System.out.println(root.getBaseURI()); // file:/R:/java-work/a.xml

NodeList getChildNodes ()

包含此节点的所有子节点的 NodeList。 (机器翻译)

final var xml = """
        <root><child-a/><child-b/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final var nodes = root.getChildNodes();
System.out.println(nodes.getLength()); // 2

System.out.println("-- nodes --");
for (int i = 0; i < nodes.getLength(); i++) {
    System.out.println(nodes.item(i));
}

// Result
// ↓
//-- nodes --
//[child-a: null]
//[child-b: null]

final var xml = """
        <root>
            <child-a/>
            <child-b/>
            <!-- comment! -->
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final var nodes = root.getChildNodes();
System.out.println(nodes.getLength()); // 7

System.out.println("-- nodes --");
for (int i = 0; i < nodes.getLength(); i++) {
    final var node = nodes.item(i);
    if (node instanceof Text text) {
        // For readability, line separators are converted to "\n" and spaces to "*".
        final var data = text.getData().replace("\n", "\\n").replace(" ", "*");
        System.out.println("[#text: " + data + "]");
    } else {
        System.out.println(node);
    }
}

// Result
// ↓
//-- nodes --
//[#text: \n****]
//[child-a: null]
//[#text: \n****]
//[child-b: null]
//[#text: \n****]
//[#comment:  comment! ]
//[#text: \n]

Object getFeature (String feature, String version)

此方法返回一个专门的对象，该对象实现指定功能和版本的专门 API，如中所述。 (机器翻译)

final var xml = """
        <root>abcd</root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

System.out.println(root.isSupported("XML", "3.0")); // true
System.out.println(root.getFeature("XML", "3.0")); // [root: null]

System.out.println(root.isSupported("XML", "4.0")); // false
System.out.println(root.getFeature("XML", "4.0")); // null

Node getFirstChild ()

此节点的第一个子节点。 (机器翻译)

final var xml = """
        <root><child-a/><child-b/><child-c/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child-a/>
//    <child-b/>
//    <child-c/>
//</root>
printDocument(document);

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node firstChild = root.getFirstChild();
System.out.println(firstChild); // [child-a: null]

final Node lastChild = root.getLastChild();
System.out.println(lastChild); // [child-c: null]

Node getLastChild ()

此节点的最后一个子节点。 (机器翻译)

final var xml = """
        <root><child-a/><child-b/><child-c/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child-a/>
//    <child-b/>
//    <child-c/>
//</root>
printDocument(document);

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node firstChild = root.getFirstChild();
System.out.println(firstChild); // [child-a: null]

final Node lastChild = root.getLastChild();
System.out.println(lastChild); // [child-c: null]

String getLocalName ()

返回此节点的限定名称的本地部分。 (机器翻译)

final var xml = """
        <ns:root xmlns:ns="sample">
            <ns:child/>
        </ns:root>
        """;

final var builder = DocumentBuilderFactory.newNSInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node child = document.getElementsByTagName("ns:child").item(0);
System.out.println(child); // [ns:child: null]

System.out.println(child.getPrefix()); // ns
System.out.println(child.getLocalName()); // child
System.out.println(child.getNamespaceURI()); // sample

String getNamespaceURI ()

此节点的命名空间 URI，如果未指定则为 null（请参阅）。 (机器翻译)

final var xml = """
        <ns:root xmlns:ns="sample">
            <ns:child/>
        </ns:root>
        """;

final var builder = DocumentBuilderFactory.newNSInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node child = document.getElementsByTagName("ns:child").item(0);
System.out.println(child); // [ns:child: null]

System.out.println(child.getPrefix()); // ns
System.out.println(child.getLocalName()); // child
System.out.println(child.getNamespaceURI()); // sample

Node getNextSibling ()

紧接此节点之后的节点。 (机器翻译)

final var xml = """
        <root><child-a/><child-b/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child-a/>
//    <child-b/>
//</root>
printDocument(document);

final Node childA = document.getDocumentElement().getFirstChild();
System.out.println(childA); // [child-a: null]

final Node childB = childA.getNextSibling();
System.out.println(childB); // [child-b: null]

final Node childC = childB.getNextSibling();
System.out.println(childC); // null

String getNodeName ()

此节点的名称取决于其类型；参见上表。 (机器翻译)

final var xml = """
        <root>
            <child aa="AA">abcd</child>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

// Element
final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child.getNodeType() == Node.ELEMENT_NODE); // true
System.out.println(child.getNodeName()); // child
System.out.println(child.getNodeValue()); // null

// Attr
final Node attr = child.getAttributes().item(0);
System.out.println(attr.getNodeType() == Node.ATTRIBUTE_NODE); // true
System.out.println(attr.getNodeName()); // aa
System.out.println(attr.getNodeValue()); // AA

// Text
final Node text = child.getFirstChild();
System.out.println(text.getNodeType() == Node.TEXT_NODE); // true
System.out.println(text.getNodeName()); // #text
System.out.println(text.getNodeValue()); // abcd

short getNodeType ()

表示底层对象类型的代码，如上所述。 (机器翻译)

final var xml = """
        <root>
            <child aa="AA">abcd</child>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

// Element
final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child.getNodeType() == Node.ELEMENT_NODE); // true
System.out.println(child.getNodeName()); // child
System.out.println(child.getNodeValue()); // null

// Attr
final Node attr = child.getAttributes().item(0);
System.out.println(attr.getNodeType() == Node.ATTRIBUTE_NODE); // true
System.out.println(attr.getNodeName()); // aa
System.out.println(attr.getNodeValue()); // AA

// Text
final Node text = child.getFirstChild();
System.out.println(text.getNodeType() == Node.TEXT_NODE); // true
System.out.println(text.getNodeName()); // #text
System.out.println(text.getNodeValue()); // abcd

String getNodeValue ()

此节点的值取决于其类型；参见上表。 (机器翻译)

final var xml = """
        <root>
            <child aa="AA">abcd</child>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

// Element
final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child.getNodeType() == Node.ELEMENT_NODE); // true
System.out.println(child.getNodeName()); // child
System.out.println(child.getNodeValue()); // null

// Attr
final Node attr = child.getAttributes().item(0);
System.out.println(attr.getNodeType() == Node.ATTRIBUTE_NODE); // true
System.out.println(attr.getNodeName()); // aa
System.out.println(attr.getNodeValue()); // AA

// Text
final Node text = child.getFirstChild();
System.out.println(text.getNodeType() == Node.TEXT_NODE); // true
System.out.println(text.getNodeName()); // #text
System.out.println(text.getNodeValue()); // abcd

Document getOwnerDocument ()

与此节点关联的 Document 对象。 (机器翻译)

final var xml = """
        <root>
            <child/>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]

final var ownerDocument = child.getOwnerDocument();
System.out.println(document.isSameNode(ownerDocument)); // true

Node getParentNode ()

此节点的父节点。 (机器翻译)

final var xml = """
        <root>
            <child>
                <child-child/>
            </child>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node childChild = document.getElementsByTagName("child-child").item(0);
System.out.println(childChild); // [child-child: null]

final Node child = childChild.getParentNode();
System.out.println(child); // [child: null]

final Node root = child.getParentNode();
System.out.println(root); // [root: null]

String getPrefix ()

此节点的命名空间前缀，如果未指定，则为 null。 (机器翻译)

final var xml = """
        <ns:root xmlns:ns="sample">
            <ns:child/>
        </ns:root>
        """;

final var builder = DocumentBuilderFactory.newNSInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node child = document.getElementsByTagName("ns:child").item(0);
System.out.println(child); // [ns:child: null]

System.out.println(child.getPrefix()); // ns
System.out.println(child.getLocalName()); // child
System.out.println(child.getNamespaceURI()); // sample

Node getPreviousSibling ()

紧接此节点之前的节点。 (机器翻译)

final var xml = """
        <root><child-y/><child-z/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child-y/>
//    <child-z/>
//</root>
printDocument(document);

final Node childZ = document.getDocumentElement().getLastChild();
System.out.println(childZ); // [child-z: null]

final Node childY = childZ.getPreviousSibling();
System.out.println(childY); // [child-y: null]

final Node childX = childY.getPreviousSibling();
System.out.println(childX); // null

String getTextContent ()

该属性返回此节点及其后代的文本内容。 (机器翻译)

final var xml = """
        <root>aaa<child>XYZ</child>bbb</root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]
System.out.println(root.getTextContent()); // aaaXYZbbb

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]
System.out.println(child.getTextContent()); // XYZ

Object getUserData (String key)

检索与此节点上的键关联的对象。 (机器翻译)

final var xml = """
        <root>
            <child-a/>
            <child-b/>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node childA = document.getElementsByTagName("child-a").item(0);
System.out.println(childA); // [child-a: null]

final Node childB = document.getElementsByTagName("child-b").item(0);
System.out.println(childB); // [child-b: null]

final var handler = new UserDataHandler() {
    @Override
    public void handle(short operation, String key, Object data, Node src, Node dst) {
        System.out.println("-- UserDataHandler.handle --");
        System.out.println(
                "operation = " + operation + " : key = " + key +
                        " : data = " + data + " : src = " + src + " : dst = " + dst);
    }
};

final var retA = childA.setUserData("a-key", "aaa", handler);
System.out.println(retA); // null

final var retB = childB.setUserData("b-key", "bbb", handler);
System.out.println(retB); // null

System.out.println(childA.getUserData("a-key")); // aaa
System.out.println(childA.getUserData("b-key")); // null

System.out.println(childB.getUserData("a-key")); // null
System.out.println(childB.getUserData("b-key")); // bbb

final var clonedNode = childA.cloneNode(false);

// Result
// ↓
//-- UserDataHandler.handle --
//operation = 1 : key = a-key : data = aaa : src = [child-a: null] : dst = [child-a: null]

final var renamedNode = document.renameNode(childB, null, "child-z");

// Result
// ↓
//-- UserDataHandler.handle --
//operation = 4 : key = b-key : data = bbb : src = [child-z: null] : dst = null

boolean hasAttributes ()

返回此节点（如果它是一个元素）是否具有任何属性。 (机器翻译)

final var xml = """
        <root>
            <child-a/>
            <child-b aa="AA" />
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node childA = document.getElementsByTagName("child-a").item(0);
System.out.println(childA); // [child-a: null]
System.out.println(childA.hasAttributes()); // false

final Node childB = document.getElementsByTagName("child-b").item(0);
System.out.println(childB); // [child-b: null]
System.out.println(childB.hasAttributes()); // true

boolean hasChildNodes ()

返回此节点是否有任何子节点。 (机器翻译)

final var xml = """
        <root><child/></root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]
System.out.println(root.hasChildNodes()); // true
System.out.println(root.getChildNodes().getLength()); // 1

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]
System.out.println(child.hasChildNodes()); // false
System.out.println(child.getChildNodes().getLength()); // 0

Node insertBefore (Node newChild, Node refChild)

在现有子节点 refChild 之前插入节点 newChild。 (机器翻译)

final var xml = """
        <root><child-z/></root>
        """;

final var document = DocumentBuilderFactory.newInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child-z/>
//</root>
printDocument(document);

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node childZ = document.getElementsByTagName("child-z").item(0);
System.out.println(childZ); // [child-z: null]

final Node childX = document.createElement("child-x");
final Node ret1 = root.insertBefore(childX, childZ);
System.out.println(ret1); // [child-x: null]

final Node childY = document.createElement("child-y");
final Node ret2 = root.insertBefore(childY, childZ);
System.out.println(ret2); // [child-y: null]

//<root>
//    <child-x/>
//    <child-y/>
//    <child-z/>
//</root>
printDocument(document);

boolean isDefaultNamespace (String namespaceURI)

此方法检查指定的 namespaceURI 是否是默认命名空间。 (机器翻译)

final var xml = """
        <root xmlns="sample1" xmlns:ns="sample2">
            <child-a/>
            <ns:child-b/>
        </root>
        """;

final var builder = DocumentBuilderFactory.newNSInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node childA = document.getElementsByTagName("child-a").item(0);
System.out.println(childA); // [child-a: null]

System.out.println(childA.getNamespaceURI()); // sample1
System.out.println(childA.isDefaultNamespace("sample1")); // true
System.out.println(childA.isDefaultNamespace("sample2")); // false

final Node childB = document.getElementsByTagName("ns:child-b").item(0);
System.out.println(childB); // [ns:child-b: null]

System.out.println(childB.getNamespaceURI()); // sample2
System.out.println(childB.isDefaultNamespace("sample1")); // true
System.out.println(childB.isDefaultNamespace("sample2")); // false

boolean isEqualNode (Node arg)

测试两个节点是否相等。 (机器翻译)

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.newDocument();

final Node nodeA1 = document.createElement("node-a");
final Node nodeA2 = document.createElement("node-a");

final Node nodeB = document.createElement("node-b");

System.out.println(nodeA1.isEqualNode(nodeA1)); // true
System.out.println(nodeA1.isEqualNode(nodeA2)); // true
System.out.println(nodeA1.isEqualNode(nodeB)); // false

System.out.println(nodeA1.isSameNode(nodeA1)); // true
System.out.println(nodeA1.isSameNode(nodeA2)); // false
System.out.println(nodeA1.isSameNode(nodeB)); // false

boolean isSameNode (Node other)

返回此节点是否与给定节点相同。 (机器翻译)

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.newDocument();

final Node nodeA1 = document.createElement("node-a");
final Node nodeA2 = document.createElement("node-a");

final Node nodeB = document.createElement("node-b");

System.out.println(nodeA1.isEqualNode(nodeA1)); // true
System.out.println(nodeA1.isEqualNode(nodeA2)); // true
System.out.println(nodeA1.isEqualNode(nodeB)); // false

System.out.println(nodeA1.isSameNode(nodeA1)); // true
System.out.println(nodeA1.isSameNode(nodeA2)); // false
System.out.println(nodeA1.isSameNode(nodeB)); // false

boolean isSupported (String feature, String version)

测试 DOM 实现是否实现了特定的功能以及该功能是否受此节点支持，如中所述。 (机器翻译)

final var xml = """
        <root>abcd</root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

System.out.println(root.isSupported("XML", "3.0")); // true
System.out.println(root.getFeature("XML", "3.0")); // [root: null]

System.out.println(root.isSupported("XML", "4.0")); // false
System.out.println(root.getFeature("XML", "4.0")); // null

String lookupNamespaceURI (String prefix)

从此节点开始查找与给定前缀关联的命名空间 URI。 (机器翻译)

final var xml = """
        <root xmlns:ns1="sample1">
            <ns1:child-a>
                <ns2:child-b xmlns:ns2="sample2"/>
            </ns1:child-a>
        </root>
        """;

final var builder = DocumentBuilderFactory.newNSInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node childA = document.getElementsByTagName("ns1:child-a").item(0);
System.out.println(childA); // [ns1:child-a: null]

System.out.println(childA.lookupNamespaceURI("ns1")); // sample1
System.out.println(childA.lookupNamespaceURI("ns2")); // null

final Node childB = document.getElementsByTagName("ns2:child-b").item(0);
System.out.println(childB); // [ns2:child-b: null]

System.out.println(childB.lookupNamespaceURI("ns1")); // sample1
System.out.println(childB.lookupNamespaceURI("ns2")); // sample2

String lookupPrefix (String namespaceURI)

从此节点开始查找与给定命名空间 URI 关联的前缀。 (机器翻译)

final var xml = """
        <root xmlns:ns1="sample1">
            <ns1:child-a>
                <ns2:child-b xmlns:ns2="sample2"/>
            </ns1:child-a>
        </root>
        """;

final var builder = DocumentBuilderFactory.newNSInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node childA = document.getElementsByTagName("ns1:child-a").item(0);
System.out.println(childA); // [ns1:child-a: null]

System.out.println(childA.lookupPrefix("sample1")); // ns1
System.out.println(childA.lookupPrefix("sample2")); // null

final Node childB = document.getElementsByTagName("ns2:child-b").item(0);
System.out.println(childB); // [ns2:child-b: null]

System.out.println(childB.lookupPrefix("sample1")); // ns1
System.out.println(childB.lookupPrefix("sample2")); // ns2

void normalize ()

将此节点下子树的完整深度中的所有文本节点（包括属性节点）放入“正常”形式，其中只有结构（例如，元素、注释、处理指令、CDATA 部分和实体引用）分隔文本节点，即，既没有相邻的文本节点也没有空的文本节点。 (机器翻译)

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.newDocument();

final Node root = document.createElement("root");

// Intentionally creates Text nodes by splitting it.
root.appendChild(document.createTextNode("aaa"));
root.appendChild(document.createTextNode("bbb"));

root.appendChild(document.createElement("child"));

root.appendChild(document.createTextNode(""));

{
    final var nodes = root.getChildNodes();
    for (int i = 0; i < nodes.getLength(); i++) {
        System.out.println(nodes.item(i));
    }

    // Result
    // ↓
    //[#text: aaa]
    //[#text: bbb]
    //[child: null]
    //[#text: ]
}

// Adjacent text nodes are combined. Empty Text nodes are deleted.
root.normalize();

{
    final var nodes = root.getChildNodes();
    for (int i = 0; i < nodes.getLength(); i++) {
        System.out.println(nodes.item(i));
    }

    // Result
    // ↓
    //[#text: aaabbb]
    //[child: null]
}

Node removeChild (Node oldChild)

从子列表中删除 oldChild 指示的子节点并返回它。 (机器翻译)

final var xml = """
        <root><child>abcd</child></root>
        """;

final var document = DocumentBuilderFactory.newInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child>abcd</child>
//</root>
printDocument(document);

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]

final Node ret = root.removeChild(child);
System.out.println(ret); // [child: null]

//<root/>
printDocument(document);

Node replaceChild (Node newChild, Node oldChild)

用 newChild 替换子节点列表中的子节点 oldChild，并返回 oldChild 节点。 (机器翻译)

final var xml = """
        <root><child-a>abcd</child-a></root>
        """;

final var document = DocumentBuilderFactory.newInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child-a>abcd</child-a>
//</root>
printDocument(document);

final Node root = document.getDocumentElement();
System.out.println(root); // [root: null]

final Node childA = document.getElementsByTagName("child-a").item(0);
System.out.println(childA); // [child-a: null]

final Node childB = document.createElement("child-b");
childB.appendChild(document.createTextNode("XYZ"));

final Node ret = root.replaceChild(childB, childA);
System.out.println(ret); // [child-a: null]

//<root>
//    <child-b>XYZ</child-b>
//</root>
printDocument(document);

void setNodeValue (String nodeValue)

此节点的值取决于其类型；参见上表。 (机器翻译)

final var xml = """
        <root><child aa="AA"/></root>
        """;

final var document = DocumentBuilderFactory.newInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child aa="AA"/>
//</root>
printDocument(document);

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]

final Node attr = child.getAttributes().item(0);
attr.setNodeValue("XYZ");

//<root>
//    <child aa="XYZ"/>
//</root>
printDocument(document);

void setPrefix (String prefix)

此节点的命名空间前缀，如果未指定，则为 null。 (机器翻译)

final var xml = """
        <ns:root xmlns:ns="sample"><ns:child/></ns:root>
        """;

final var document = DocumentBuilderFactory.newNSInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

//<ns:root xmlns:ns="sample">
//    <ns:child/>
//</ns:root>
printDocument(document);

final Node child = document.getElementsByTagName("ns:child").item(0);
System.out.println(child); // [ns:child: null]

child.setPrefix("xx");

//<ns:root xmlns:ns="sample">
//    <xx:child xmlns:xx="sample"/>
//</ns:root>
printDocument(document);

void setTextContent (String textContent)

该属性返回此节点及其后代的文本内容。 (机器翻译)

final var xml = """
        <root><child/></root>
        """;

final var document = DocumentBuilderFactory.newInstance()
        .newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes()));

//<root>
//    <child/>
//</root>
printDocument(document);

final Node child = document.getElementsByTagName("child").item(0);
System.out.println(child); // [child: null]

child.setTextContent("abcd");

//<root>
//    <child>abcd</child>
//</root>
printDocument(document);

Object setUserData (String key, Object data, UserDataHandler handler)

将一个对象与此节点上的一个键关联起来。 (机器翻译)

final var xml = """
        <root>
            <child-a/>
            <child-b/>
        </root>
        """;

final var builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
final var document = builder.parse(new ByteArrayInputStream(xml.getBytes()));

final Node childA = document.getElementsByTagName("child-a").item(0);
System.out.println(childA); // [child-a: null]

final Node childB = document.getElementsByTagName("child-b").item(0);
System.out.println(childB); // [child-b: null]

final var handler = new UserDataHandler() {
    @Override
    public void handle(short operation, String key, Object data, Node src, Node dst) {
        System.out.println("-- UserDataHandler.handle --");
        System.out.println(
                "operation = " + operation + " : key = " + key +
                        " : data = " + data + " : src = " + src + " : dst = " + dst);
    }
};

final var retA = childA.setUserData("a-key", "aaa", handler);
System.out.println(retA); // null

final var retB = childB.setUserData("b-key", "bbb", handler);
System.out.println(retB); // null

System.out.println(childA.getUserData("a-key")); // aaa
System.out.println(childA.getUserData("b-key")); // null

System.out.println(childB.getUserData("a-key")); // null
System.out.println(childB.getUserData("b-key")); // bbb

final var clonedNode = childA.cloneNode(false);

// Result
// ↓
//-- UserDataHandler.handle --
//operation = 1 : key = a-key : data = aaa : src = [child-a: null] : dst = [child-a: null]

final var renamedNode = document.renameNode(childB, null, "child-z");

// Result
// ↓
//-- UserDataHandler.handle --
//operation = 4 : key = b-key : data = bbb : src = [child-z: null] : dst = null

API 示例
- DocumentBuilder
- DocumentBuilderFactory
- DOMImplementation
- DOMImplementationLS
- LSSerializer
- Node
  - Attr
  - CharacterData
  - Comment
  - Document
  - Element
  - Entity
  - EntityReference
  - Text
- Transformer
- TransformerFactory

Java : Node (XML) 示例

简介

Fields

static final short ATTRIBUTE_NODE

static final short CDATA_SECTION_NODE

static final short COMMENT_NODE

static final short DOCUMENT_FRAGMENT_NODE

static final short DOCUMENT_NODE

static final short DOCUMENT_POSITION_CONTAINED_BY

static final short DOCUMENT_POSITION_CONTAINS

static final short DOCUMENT_POSITION_DISCONNECTED

static final short DOCUMENT_POSITION_FOLLOWING

static final short DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC

static final short DOCUMENT_POSITION_PRECEDING

static final short DOCUMENT_TYPE_NODE

static final short ELEMENT_NODE

static final short ENTITY_NODE

static final short ENTITY_REFERENCE_NODE

static final short NOTATION_NODE

static final short PROCESSING_INSTRUCTION_NODE

static final short TEXT_NODE

Methods

Node appendChild (Node newChild)

Node cloneNode (boolean deep)

short compareDocumentPosition (Node other)

NamedNodeMap getAttributes ()

String getBaseURI ()

NodeList getChildNodes ()

Object getFeature (String feature, String version)

Node getFirstChild ()

Node getLastChild ()

String getLocalName ()

String getNamespaceURI ()

Node getNextSibling ()

String getNodeName ()

short getNodeType ()

String getNodeValue ()

Document getOwnerDocument ()

Node getParentNode ()

String getPrefix ()

Node getPreviousSibling ()

String getTextContent ()

Object getUserData (String key)

boolean hasAttributes ()

boolean hasChildNodes ()

Node insertBefore (Node newChild, Node refChild)

boolean isDefaultNamespace (String namespaceURI)

boolean isEqualNode (Node arg)

boolean isSameNode (Node other)

boolean isSupported (String feature, String version)

String lookupNamespaceURI (String prefix)

String lookupPrefix (String namespaceURI)

void normalize ()

Node removeChild (Node oldChild)

Node replaceChild (Node newChild, Node oldChild)

void setNodeValue (String nodeValue)

void setPrefix (String prefix)

void setTextContent (String textContent)

Object setUserData (String key, Object data, UserDataHandler handler)

相关文章