Java 从复杂的空元素解析XML属性
我有一个以下模式的xml文件,其中包含一些复杂的空元素(没有内容的元素,只有属性)Java 从复杂的空元素解析XML属性,java,xml,Java,Xml,我有一个以下模式的xml文件,其中包含一些复杂的空元素(没有内容的元素,只有属性) 我无法解析它们的属性。这就是我到目前为止所做的: DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document document = builder.parse(inputStream); Elemen
我无法解析它们的属性。这就是我到目前为止所做的:
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(inputStream);
Element itemsElement = document.getDocumentElement();
if (itemsElement.getTagName().equals(TAG_ITEMS)) {
NodeList nodeList = itemsElement.getChildNodes();
for (int i = 0; i < nodeList.getLength(); i++) {
// process each item node
Node node = nodeList.item(i);
if (node.getNodeType() == Node.TEXT_NODE) { // Is this the right way?
Text text = (Text) node;
// Do stuff with attributes
}
}
}
DocumentBuilderFactory=DocumentBuilderFactory.newInstance();
DocumentBuilder=factory.newDocumentBuilder();
Document=builder.parse(inputStream);
元素itemsElement=document.getDocumentElement();
if(itemsElement.getTagName().equals(TAG_ITEMS)){
NodeList NodeList=itemsElement.getChildNodes();
for(int i=0;i
我无法将这些
Text
节点强制转换为元素
节点并获取属性,我无法使用getAttributes
-NPE在NamedNodeMap attributes.getLength()
处从节点获取属性,我无法将其强制转换为Text
并获取属性。如何解析属性?您对项
中节点的文本上下文不感兴趣,而是对节点项
的属性感兴趣。你可以按以下步骤进行:
//process each item node
Node node = nodeList.item(i);
if (node.getNodeName().equals("item")) {
NamedNodeMap attributes = node.getAttributes();
System.out.printf("id=%s, name=%s%n",
attributes.getNamedItem("id").getTextContent(),
attributes.getNamedItem("name").getTextContent());
}
这将打印:
id=0, name=a
id=1, name=b
假设您想要获得节点的个性化属性,您需要从两件事中选择一件(或者根据您的需要选择两者) 您需要测试当前节点是否为
元素\u节点
,或者当前节点的名称是否等于项
(假设所有节点名称相同),例如
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
public class Test {
public static final String TAG_ITEMS = "items";
public static void main(String[] args) {
try (InputStream is = Test.class.getResourceAsStream("/Test.xml")) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(is);
Element itemsElement = document.getDocumentElement();
if (itemsElement.getTagName().equals(TAG_ITEMS)) {
NodeList nodeList = itemsElement.getChildNodes();
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
NamedNodeMap attributes = node.getAttributes();
Node idAtt = attributes.getNamedItem("id");
Node nameAtt = attributes.getNamedItem("name");
System.out.println("id = " + idAtt.getNodeValue());
System.out.println("name = " + nameAtt.getNodeValue());
}
}
}
} catch (Exception exp) {
exp.printStackTrace();
}
}
}
所有这些都可以通过使用XPath大大减少,例如,如果所有item
节点都是相同的名称,那么您可以使用
/items/item
作为查询。如果节点名称不同,但属性相同,则可以使用
/items/*[@id]
将列出具有id
属性的items
下的所有节点,或
/items/*[@name]
它将列出具有名称
属性的项下的所有节点
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class Test {
public static void main(String[] args) {
try (InputStream is = Test.class.getResourceAsStream("/Test.xml")) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(is);
XPath xpath = XPathFactory.newInstance().newXPath();
XPathExpression expression = xpath.compile("/items/item");
NodeList nodes = (NodeList) expression.evaluate(document, XPathConstants.NODESET);
process(nodes);
expression = xpath.compile("/items/*[@id]");
nodes = (NodeList) expression.evaluate(document, XPathConstants.NODESET);
process(nodes);
expression = xpath.compile("/items/*[@name]");
nodes = (NodeList) expression.evaluate(document, XPathConstants.NODESET);
process(nodes);
} catch (Exception exp) {
exp.printStackTrace();
}
}
protected static void process(NodeList nodes) {
for (int index = 0; index < nodes.getLength(); index++) {
Node item = nodes.item(index);
NamedNodeMap attributes = item.getAttributes();
Node idAtt = attributes.getNamedItem("id");
Node nameAtt = attributes.getNamedItem("name");
System.out.println("id = " + idAtt.getNodeValue() + "; name = " + nameAtt.getNodeValue());
}
}
}
import java.io.InputStream;
导入javax.xml.parsers.DocumentBuilder;
导入javax.xml.parsers.DocumentBuilderFactory;
导入javax.xml.xpath.xpath;
导入javax.xml.xpath.XPathConstants;
导入javax.xml.xpath.XPathExpression;
导入javax.xml.xpath.XPathFactory;
导入org.w3c.dom.Document;
导入org.w3c.dom.NamedNodeMap;
导入org.w3c.dom.Node;
导入org.w3c.dom.NodeList;
公开课考试{
公共静态void main(字符串[]args){
try(InputStream=Test.class.getResourceAsStream(“/Test.xml”)){
DocumentBuilderFactory工厂=DocumentBuilderFactory.newInstance();
DocumentBuilder=factory.newDocumentBuilder();
Document=builder.parse(is);
XPath=XPathFactory.newInstance().newXPath();
XPathExpression表达式=xpath.compile(“/items/item”);
NodeList nodes=(NodeList)expression.evaluate(文档,XPathConstants.NODESET);
进程(节点);
expression=xpath.compile(“/items/*[@id]”);
nodes=(NodeList)expression.evaluate(文档,XPathConstants.NODESET);
进程(节点);
expression=xpath.compile(“/items/*[@name]”);
nodes=(NodeList)expression.evaluate(文档,XPathConstants.NODESET);
进程(节点);
}捕获(异常扩展){
exp.printStackTrace();
}
}
受保护的静态无效进程(节点列表节点){
对于(int index=0;index
唯一改变的是属性值,如示例中所示。这取决于单个过程,可能有一点,因为XPath需要遍历DOM以构建其列表,然后您需要单独处理它,这就更简单了。。。
/items/*[@name]
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class Test {
public static void main(String[] args) {
try (InputStream is = Test.class.getResourceAsStream("/Test.xml")) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(is);
XPath xpath = XPathFactory.newInstance().newXPath();
XPathExpression expression = xpath.compile("/items/item");
NodeList nodes = (NodeList) expression.evaluate(document, XPathConstants.NODESET);
process(nodes);
expression = xpath.compile("/items/*[@id]");
nodes = (NodeList) expression.evaluate(document, XPathConstants.NODESET);
process(nodes);
expression = xpath.compile("/items/*[@name]");
nodes = (NodeList) expression.evaluate(document, XPathConstants.NODESET);
process(nodes);
} catch (Exception exp) {
exp.printStackTrace();
}
}
protected static void process(NodeList nodes) {
for (int index = 0; index < nodes.getLength(); index++) {
Node item = nodes.item(index);
NamedNodeMap attributes = item.getAttributes();
Node idAtt = attributes.getNamedItem("id");
Node nameAtt = attributes.getNamedItem("name");
System.out.println("id = " + idAtt.getNodeValue() + "; name = " + nameAtt.getNodeValue());
}
}
}