我第一次在Java中使用XML文件，我需要一些帮助。我正在尝试使用Java
将XML文件拆分为多个XML文件<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<products>
<product>
<description>Sony 54.6" (Diag) Xbr Hx929 Internet Tv</description>
<gtin>00027242816657</gtin>
<price>2999.99</price>
<orderId>2343</orderId>
<supplier>Sony</supplier>
</product>
<product>
<description>Apple iPad 2 with Wi-Fi 16GB - iOS 5 - Black
</description>
<gtin>00885909464517</gtin>
<price>399.0</price>
<orderId>2343</orderId>
<supplier>Apple</supplier>
</product>
<product>
<description>Sony NWZ-E464 8GB E Series Walkman Video MP3 Player Blue
</description>
<gtin>00027242831438</gtin>
<price>91.99</price>
<orderId>2343</orderId>
<supplier>Sony</supplier>
</product>
<product>
<description>Apple MacBook Air A 11.6" Mac OS X v10.7 Lion MacBook
</description>
<gtin>00885909464043</gtin>
<price>1149.0</price>
<orderId>2344</orderId>
<supplier>Apple</supplier>
</product>
<product>
<description>Panasonic TC-L47E50 47" Smart TV Viera E50 Series LED
HDTV</description>
<gtin>00885170076471</gtin>
<price>999.99</price>
<orderId>2344</orderId>
<supplier>Panasonic</supplier>
</product>
</products>
我试图获得三个XML文档，如：
<?xml version="1.0" encoding="UTF-8"?>
<products>
<product>
<description>Sony 54.6" (Diag) Xbr Hx929 Internet Tv</description>
<gtin>00027242816657</gtin>
<price currency="USD">2999.99</price>
<orderid>2343</orderid>
</product>
<product>
<description>Sony NWZ-E464 8GB E Series Walkman Video MP3 Player Blue</description>
<gtin>00027242831438</gtin>
<price currency="USD">91.99</price>
<orderid>2343</orderid>
</product>
</products>
每个供应商一个。我该怎么收到它？对此的任何帮助都会很棒。
答案 0 :(得分：1)
确保将“inputFile”中的路径更改为您的文件以及输出部分：
StreamResult result = new StreamResult(new File("C:\xmls\" + supplier.trim() + ".xml"));
这是您的代码。
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
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.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class ExtractXml
{
/**
* @param args
*/
public static void main(String[] args) throws Exception
{
String inputFile = "resources/products.xml";
File xmlFile = new File(inputFile);
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(xmlFile);
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true); // never forget this!
XPathFactory xfactory = XPathFactory.newInstance();
XPath xpath = xfactory.newXPath();
XPathExpression allProductsExpression = xpath.compile("//product/supplier/text()");
NodeList productNodes = (NodeList) allProductsExpression.evaluate(doc, XPathConstants.NODESET);
//Save all the products
List<String> suppliers = new ArrayList<String>();
for (int i=0; i<productNodes.getLength(); ++i)
{
Node productName = productNodes.item(i);
System.out.println(productName.getTextContent());
suppliers.add(productName.getTextContent());
}
//Now we create the split XMLs
for (String supplier : suppliers)
{
String xpathQuery = "/products/product[supplier='" + supplier + "']";
xpath = xfactory.newXPath();
XPathExpression query = xpath.compile(xpathQuery);
NodeList productNodesFiltered = (NodeList) query.evaluate(doc, XPathConstants.NODESET);
System.out.println("Found " + productNodesFiltered.getLength() +
" product(s) for supplier " + supplier);
//We store the new XML file in supplierName.xml e.g. Sony.xml
Document suppXml = dBuilder.newDocument();
//we have to recreate the root node <products>
Element root = suppXml.createElement("products");
suppXml.appendChild(root);
for (int i=0; i<productNodesFiltered.getLength(); ++i)
{
Node productNode = productNodesFiltered.item(i);
//we append a product (cloned) to the new file
Node clonedNode = productNode.cloneNode(true);
suppXml.adoptNode(clonedNode); //We adopt the orphan :)
root.appendChild(clonedNode);
}
//At the end, we save the file XML on disk
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
DOMSource source = new DOMSource(suppXml);
StreamResult result = new StreamResult(new File("resources/" + supplier.trim() + ".xml"));
transformer.transform(source, result);
System.out.println("Done for " + supplier);
}
}
}
答案 1 :(得分：0)
您可以在这里查看如何使用Java在Java中解析XML文档： DOM XML Parser Example
这里，如何编写新的XML文件： Create XML file using java
此外，您可以学习XPath以轻松选择节点：Java Xpath expression
如果表演不是您的目标，首先，一旦您加载了DOM和Xpath，就可以使用以下XPath查询检索xml文档中的所有供应商
//supplier/text()
你会得到类似的东西：
Text='Sony'
Text='Apple'
Text='Sony'
Text='Apple'
Text='Panasonic'
然后我会将这些结果放在ArraryList或其他任何内容中。第二步是该集合的迭代，并为每个项目查询XML输入文档，以便提取特定供应商的所有节点：
/products/product[supplier='Sony']
当然在java中你必须以动态的方式构建最后的xpath查询：
String xpathQuery = "/products/product/[supplier='" + currentValue + "']
之后，您将获得与您指定的供应商匹配的节点列表。下一步是构建新的XML DOM并将其保存在文件中。
答案 2 :(得分：0)
DOM解析器将消耗更多内存。我更喜欢使用SAX解析器来读取XML并写入。
答案 3 :(得分：0)
我喜欢Xmappr（https://code.google.com/p/xmappr/）的方法，你可以使用简单的注释：
首先是简单地保存Product-instances列表的根元素Products
@RootElement
public class Products {
@Element
public List<Product> product;
}
然后是产品类
@RootElement
public class Product {
@Element
public String description;
@Element
public String supplier;
@Element
public String gtin;
@Element
public String price;
@Element
public String orderId;
}
然后您只需从产品中获取产品实例：
public static void main(String[] args) throws FileNotFoundException {
Reader reader = new FileReader("test.xml");
Xmappr xm = new Xmappr(Products.class);
Products products = (Products) xm.fromXML(reader);
// fetch list of products
List<Product> listOfProducts = products.product;
// do sth with the products in the list
for (Product product : listOfProducts) {
System.out.println(product.description);
}
}
然后你可以随意对产品做任何事情（例如根据供应商对它们进行分类并将它们放到xml文件中）
答案 4 :(得分：0)
考虑此xml
<?xml version="1.0"?>
<SSNExportDocument xmlns="urn:com:ssn:schema:export:SSNExportFormat.xsd" Version="0.1" DocumentID="b482350d-62bb-41be-b792-8a9fe3884601-1" ExportID="b482350d-62bb-41be-b792-8a9fe3884601" JobID="464" RunID="3532468" CreationTime="2019-04-16T02:20:01.332-04:00" StartTime="2019-04-15T20:20:00.000-04:00" EndTime="2019-04-16T02:20:00.000-04:00">
<MeterData MeterName="MUNI1-11459398" UtilDeviceID="11459398" MacID="00:12:01:fae:fe:00:d5:fc">
<RegisterData StartTime="2019-04-15T20:00:00.000-04:00" EndTime="2019-04-15T20:00:00.000-04:00" NumberReads="1">
<RegisterRead ReadTime="2019-04-15T20:00:00.000-04:00" GatewayCollectedTime="2019-04-16T01:40:06.214-04:00" RegisterReadSource="REG_SRC_TYPE_EO_CURR_READ" Season="-1">
<Tier Number="0">
<Register Number="1" Summation="5949.1000" SummationUOM="GAL"/>
</Tier>
</RegisterRead>
</RegisterData>
</MeterData>
<MeterData MeterName="MUNI4-11460365" UtilDeviceID="11460365" MacID="00:11:01:bc:fe:00:d3:f9">
<RegisterData StartTime="2019-04-15T20:00:00.000-04:00" EndTime="2019-04-15T20:00:00.000-04:00" NumberReads="1">
<RegisterRead ReadTime="2019-04-15T20:00:00.000-04:00" GatewayCollectedTime="2019-04-16T01:40:11.082-04:00" RegisterReadSource="REG_SRC_TYPE_EO_CURR_READ" Season="-1">
<Tier Number="0">
<Register Number="1" Summation="136349.9000" SummationUOM="GAL"/>
</Tier>
</RegisterRead>
</RegisterData>
</MeterData>
我们可以使用JAXB将您的xml标记转换为对象。然后我们可以和他们一起玩。
File xmlFile = new File("input.xml");
jaxbContext = JAXBContext.newInstance(SSNExportDocument.class);
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
SSNExportDocument ssnExpDoc = (SSNExportDocument) jaxbUnmarshaller.unmarshal(xmlFile);
MeterData mD = new MeterData();
Map<String, List<MeterData>> meterMapper = new HashMap<String, List<MeterData>>(); // Phantom Reference
for (MeterData mData : ssnExpDoc.getMeterData()) {
String meterFullName = mData.getMeterName();
String[] splitMeterName = meterFullName.split("-");
List<MeterData> _meterDataList = meterMapper.get(splitMeterName[0]);// o(1)
if (_meterDataList == null) {
_meterDataList = new ArrayList<>();
_meterDataList.add(mData);
meterMapper.put(splitMeterName[0], _meterDataList);
_meterDataList = null;
} else {
_meterDataList.add(mData);
}
}
meterMapper包含针对对象列表的标签名称
然后将内容编组为
JAXBContext jaxbContext = JAXBContext.newInstance(SSNExportDocument.class);
// Create Marshaller
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
// Required formatting??
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
jaxbMarshaller.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE);
//jaxbMarshaller.setProperty("com.sun.xml.bind.xmlDeclaration", Boolean.FALSE);
// Print XML String to Console
StringWriter sw = new StringWriter();
// Write XML to StringWriter
jaxbMarshaller.marshal(employee, sw);
// Verify XML Content
String xmlContent = sw.toString();
System.out.println(xmlContent);
答案 5 :(得分：0)
不是完美的解决方案，但在大多数情况下都有效。不得不玩一些字符串操作才能使它工作。基本上，此解决方案将给定元素的给定 XML 拆分并形成子 XML 并将其写入列表。
public static void main(String[] args) {
java.io.File inputFile = new java.io.File("input.xml");
String elementSplitString = "product";
java.io.InputStream inputStream = null;
try {
inputStream = new java.io.BufferedInputStream(new java.io.FileInputStream(inputFile));
javax.xml.stream.XMLInputFactory inputFactory = javax.xml.stream.XMLInputFactory.newInstance();
javax.xml.stream.XMLOutputFactory outputFactory = javax.xml.stream.XMLOutputFactory.newInstance();
javax.xml.stream.XMLEventReader reader = inputFactory.createXMLEventReader(inputStream);
javax.xml.stream.XMLEventWriter writer = null;
StringWriter parentXMLStringWriter = new StringWriter();
javax.xml.stream.XMLEventWriter headerWriter = outputFactory.createXMLEventWriter(parentXMLStringWriter);
StringWriter stringWriter = null;
String lastReadEvent = "";
boolean splitElementFound = false;
List<StringBuilder> list = new ArrayList<StringBuilder>();
while (reader.hasNext()) {
javax.xml.stream.events.XMLEvent event = reader.nextEvent();
switch(event.getEventType()) {
case javax.xml.stream.XMLStreamConstants.START_ELEMENT:
javax.xml.stream.events.StartElement startElement = (javax.xml.stream.events.StartElement)event;
if (startElement.getName().getLocalPart().equals(elementSplitString)) {
splitElementFound = true;
stringWriter = new StringWriter();
writer = outputFactory.createXMLEventWriter(stringWriter);
if (writer != null) writer.add(event);
} else if(writer != null)
writer.add(event);
break;
case javax.xml.stream.XMLStreamConstants.END_ELEMENT:
javax.xml.stream.events.EndElement endElement = (javax.xml.stream.events.EndElement)event;
if (endElement.getName().getLocalPart().equals(elementSplitString)) {
if (writer != null) writer.add(event);
writer.close();
StringBuilder builder = new StringBuilder();
String parentXML = parentXMLStringWriter.toString();
builder.append(parentXML.subSequence(0, parentXML.indexOf(">", parentXML.indexOf(lastReadEvent)) + 1));
builder.append(stringWriter.toString());
builder.append(parentXML.substring(parentXML.indexOf(">", parentXML.indexOf(lastReadEvent)) + 2));
list.add(builder);
writer = null;
}else if(writer != null)
writer.add(event);
break;
default:
if (writer != null)
writer.add(event);
break;
}
if(!splitElementFound) {
if(event instanceof javax.xml.stream.events.StartElement)
lastReadEvent = ((javax.xml.stream.events.StartElement)event).getName().getLocalPart();
else if(event instanceof javax.xml.stream.events.EndElement)
lastReadEvent = ((javax.xml.stream.events.EndElement)event).getName().getLocalPart();
headerWriter.add(event);
}else {
headerWriter.close();
}
}
headerWriter = null;
reader.close();
if (writer != null) writer.close();
} catch(Throwable ex) {
ex.printStackTrace();
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (java.io.IOException ex) {
// do nothing
}
}
}
}
答案 6 :(得分：-1)
如果你有XML方言的Schema（XSD），那么Dom的替代方案就是JAXB。