这是我的xml代码......
<flow>
<TaskID>100</TaskID>
<TaskID>101</TaskID>
<TaskID>102</TaskID>
<TaskID>103</TaskID>
</flow>
我想知道如何在java中的for循环中获取taskID值。请帮帮我......
答案 0 :(得分：6)
DOM解析器解决方案，相当简单，无需额外的库。
public static void main(String[] args) throws SAXException, IOException,
ParserConfigurationException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
String input = "<outer>";
input += "<otherstuff><TaskID>123</TaskID></otherstuff>";
input += "<flow>";
input += "<TaskID>100</TaskID>";
input += "<TaskID>101</TaskID>";
input += "<TaskID>102</TaskID>";
input += "<TaskID>103</TaskID>";
input += "</flow>";
input += "</outer>";
Document document = builder.parse(new InputSource(new StringReader(
input)));
NodeList flowList = document.getElementsByTagName("flow");
for (int i = 0; i < flowList.getLength(); i++) {
NodeList childList = flowList.item(i).getChildNodes();
for (int j = 0; j < childList.getLength(); j++) {
Node childNode = childList.item(j);
if ("TaskID".equals(childNode.getNodeName())) {
System.out.println(childList.item(j).getTextContent()
.trim());
}
}
}
}
如果输入来自文件，则需要使用FileReader。
Document document = builder.parse(new InputSource(new FileReader(
new File("foo.xml"))));
getElementsByTagName（）的替代方法是XPath，一种XML的查询语言，如果您有一组复杂的条件要匹配，这将特别有用。
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
XPathExpression expr = xpath.compile("//flow/TaskID/text()");
Object result = expr.evaluate(document, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getTextContent());
}
如果您的XML文件很大，例如100 MB / GB或者您在低内存平台上，那么请考虑使用SAX解析器。
String input = "<flow><TaskID>100</TaskID><TaskID>101</TaskID><TaskID>102</TaskID><TaskID>103</TaskID></flow>";
SAXParser sax = SAXParserFactory.newInstance().newSAXParser();
DefaultHandler handler = new DefaultHandler() {
private StringBuilder buffer = new StringBuilder();
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if ("TaskID".equals(qName)) {
System.out.println(buffer);
buffer = new StringBuilder();
}
}
@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
buffer.append(ch, start, length);
}
@Override
public void startElement(String uri, String localName,
String qName, Attributes attributes) throws SAXException {
buffer = new StringBuilder();
}
};
sax.parse(new InputSource(new StringReader(input)), handler);
答案 1 :(得分：4)
以下是使用JDOM的示例，它提供了比现有Java XML解析器更令人愉快的API：
import java.io.File;
import org.jdom2.*;
import org.jdom2.input.*;
public class Test {
// TODO: More appropriate exception handling :)
public static void main (String[] args) throws Exception {
SAXBuilder builder = new SAXBuilder();
Document doc = builder.build(new File("test.xml"));
Element root = doc.getRootElement();
for (Element element : root.getChildren("TaskID")) {
System.out.println(element.getText());
}
}
}
当然，这假设XML文档足够小，无法加载到内存中。
（显然你也可以使用内置的库，如果你没有做很多 XML工作，那就没问题了 - 如果你做的话，我发现它们有点原始任何大量的工作。）
答案 2 :(得分：0)
使用xpath以下是更多信息：
答案 3 :(得分：0)
我个人使用JDOM库进行所有XML操作。以下是我将如何操作;
String xml = "<flow> " +
"<TaskID>100</TaskID>" +
"<TaskID>101</TaskID>" +
"<TaskID>102</TaskID>" +
"<TaskID>103</TaskID>" +
"</flow>";
org.jdom.Document doc = new SAXBuilder().build(new StringReader(xml));
org.jdom.Element rootElement = doc.getRootElement();
List<Element> eles = rootElement.getChildren("TaskID");
for(Element el : eles)
System.out.println(el.getName()+" : "+el.getValue());
您可以在此处获取文档：http://www.jdom.org/
答案 4 :(得分：0)
使用SAX阅读Xml儿童
<?xml version="1.0"?>
<Patriarch>
<name>Bill</name>
<wife>
<name>Vi</name>
</wife>
<son>
<name>Bill</name>
</son>
<daughter>
<name>Jeri</name>
<husband>
<name>Mark</name>
</husband>
<son>
<name>Greg</name>
</son>
<son>
<name>Tim</name>
</son>
<son>
<name>Mark</name>
</son>
<son>
<name>Josh</name>
<wife>
<name>Kristine</name>
</wife>
<son>
<name>Blake</name>
</son>
<daughter>
<name>Liah</name>
</daughter>
</son>
</daughter>
</Patriarch>
和Java代码：
public class ParseXmlSAX {
public static void main(String[] args) {
new ParseXmlSAX("file.xml");
}
public ParseXmlSAX(final String file) {
try {
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
DefaultHandler handler = new DefaultHandler() {
String key = null;
public void startElement(String uri, String localName, String qName, Attributes attributes)
throws SAXException {
if (key == null)
key = "|";
else
key += qName + "|";
}
public void endElement(String uri, String localName, String qName) throws SAXException {
if (!key.equals("|"))
key = key.substring(0, key.lastIndexOf(qName));
}
public void characters(char ch[], int start, int length) throws SAXException {
String conteudo = new String(ch, start, length).trim();
if (!conteudo.isEmpty()) {
System.out.println(key + " = " + conteudo);
}
}
};
saxParser.parse(this.getClass().getResourceAsStream(file), handler);
} catch (Exception e) {
e.printStackTrace();
}
}
}
答案 5 :(得分：-1)
public class Modifier {
public void modifyXML() {
String strSrcFile = "E:\\projects\\input\\sample.xml";
String strOutputFile = "E:\\projects\\output\\sample.xml";
try {
DocumentBuilderFactory docFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse(strSrcFile);
Node company = doc.getFirstChild();
System.out.println(company.hasChildNodes());
NodeList nl = company.getChildNodes();
for (int i = 0; i < nl.getLength(); i++) {
Node node = nl.item(i);
// System.out.println("inner node::"+node.getNodeName());
if (node.hasChildNodes()) {
System.out.println("outer node::" + node.getNodeName());
readChildNodes(node);
} else {
}
}
TransformerFactory transformerFactory = TransformerFactory
.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(strOutputFile));
transformer.transform(source, result);
} catch (Exception ee) {
ee.printStackTrace();
}
// Get the root element
}
public void readChildNodes(Node node)
{
NodeList nl = node.getChildNodes();
for (int i = 0; i < nl.getLength(); i++) {
Node innernode = nl.item(i);
//System.out.println("mediam stage node::"+innernode.getNodeName());
if (innernode.hasChildNodes()) {
System.out.println("inner node::"+innernode.getNodeName());
readChildNodes(innernode);
}
else{
System.out.println("node dont have childs node::"+innernode.getNodeName());
}
}
}
public void replaceGraphicCode(Node innernode) {
NamedNodeMap attr = innernode.getAttributes();
Node nodeAttr = attr.getNamedItem("id");
String IDvalue = nodeAttr.getTextContent();
// nodeAttr.setTextContent("2");
}
public void replaceOriginator(Node innernode) {
NamedNodeMap attr = innernode.getAttributes();
Node nodeAttr = attr.getNamedItem("enterpriseCode");
}
public static void main(String[] args) {
Modifier objModifier = new Modifier();
objModifier.modifyXML();
}
}