用于复杂/大型XML的Java Stax
我有一个4.2GB的XML文件!显然,解析整个DOM是不实际的。我一直在研究SAX和STAX来完成对这个巨大XML文件的解析。然而,我看到的所有例子都很简单。我正在处理的XML文件已嵌套在嵌套上。在某些领域,它可以达到10+个级别 我找到了这个教程,但不确定它是否是一个可行的解决方案 (使用STAX的botton示例) 我不确定如何处理嵌套对象 我创建了Java对象来模拟XML的结构。这里有一些,太多了,无法展示 Record.java用于复杂/大型XML的Java Stax,java,xml,stax,Java,Xml,Stax,我有一个4.2GB的XML文件!显然,解析整个DOM是不实际的。我一直在研究SAX和STAX来完成对这个巨大XML文件的解析。然而,我看到的所有例子都很简单。我正在处理的XML文件已嵌套在嵌套上。在某些领域,它可以达到10+个级别 我找到了这个教程,但不确定它是否是一个可行的解决方案 (使用STAX的botton示例) 我不确定如何处理嵌套对象 我创建了Java对象来模拟XML的结构。这里有一些,太多了,无法展示 Record.java public class Record implement
public class Record implements Serializable {
String uid;
StaticData staticData;
DynamicData dynamicData;
}
Summary.java
public class Summary {
EWUID ewuid;
PubInfo pubInfo;
Titles titles;
Names names;
DocTypes docTypes;
Publishers publishers;
}
EWUID.java
public class EWUID {
String collId;
String edition;
}
PubInfo.java
public class PubInfo {
String coverDate;
String hasAbstract;
String issue;
String pubMonth;
String pubType;
String pubYear;
String sortDate;
String volume;
}
这是我到目前为止想出的代码
public class TRWOSParser {
XMLEventReader eventReader;
XMLInputFactory inputFactory;
InputStream inputStream;
public TRWOSParser(String file) throws FileNotFoundException, XMLStreamException {
inputFactory = XMLInputFactory.newInstance();
inputStream = new FileInputStream(file);
eventReader = inputFactory.createXMLEventReader(inputStream);
}
public void parse() throws XMLStreamException{
while (eventReader.hasNext()) {
XMLEvent event = eventReader.nextEvent();
if (event.isStartElement()) {
StartElement startElement = event.asStartElement();
if (startElement.getName().getLocalPart().equals("record")) {
Record record = new Record();
Iterator<Attribute> attributes = startElement.getAttributes();
while (attributes.hasNext()) {
Attribute attribute = attributes.next();
if (attribute.getName().toString().equals("UID")) {
System.out.println("UID: " + attribute.getValue());
}
}
}
}
}
}
}
公共类TRWOSParser{
XMLEventReader事件阅读器;
XMLInputFactory输入工厂;
输入流输入流;
公共TRWOSParser(字符串文件)抛出FileNotFoundException、XMLStreamException{
inputFactory=XMLInputFactory.newInstance();
inputStream=新文件inputStream(文件);
eventReader=inputFactory.createXMLEventReader(inputStream);
}
public void parse()引发XMLStreamException{
while(eventReader.hasNext()){
XMLEvent=eventReader.nextEvent();
if(event.isStartElement()){
StartElement StartElement=event.asStartElement();
if(startElement.getName().getLocalPart().equals(“记录”)){
记录=新记录();
迭代器属性=startElement.getAttributes();
while(attributes.hasNext()){
Attribute=attributes.next();
if(attribute.getName().toString().equals(“UID”)){
System.out.println(“UID:+attribute.getValue());
}
}
}
}
}
}
}
更新:
XML中的数据已获得许可,因此无法显示完整文件。这是一个非常非常小的片段,我在其中对数据进行了置乱
<?xml version="1.0" encoding="UTF-8"?>
<records>
<REC>
<UID>WOS:000310438600004</UID>
<static_data>
<summary>
<EWUID>
<WUID coll_id="WOS" />
<edition value="WOS.SCI" />
</EWUID>
<pub_info coverdate="NOV 2012" has_abstract="N" issue="5" pubmonth="NOV" pubtype="Journal" pubyear="2012" sortdate="2012-11-01" vol="188">
<page begin="1662" end="1663" page_count="2">1662-1663</page>
</pub_info>
<titles count="6">
<title type="source">JOURNAL OF UROLOGY</title>
<title type="source_abbrev">J UROLOGY</title>
<title type="abbrev_iso">J. Urol.</title>
<title type="abbrev_11">J UROL</title>
<title type="abbrev_29">J UROL</title>
<title type="item">Something something</title>
</titles>
<names count="1">
<name addr_no="1 2 3" reprint="Y" role="author" seq_no="1">
<display_name>John Doe</display_name>
<full_name>John Doe</full_name>
<wos_standard>Doe, John</wos_standard>
<first_name>John</first_name>
<last_name>Doe</last_name>
</name>
</names>
<doctypes count="1">
<doctype>Editorial Material</doctype>
</doctypes>
<publishers>
<publisher>
<address_spec addr_no="1">
<full_address>360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA</full_address>
<city>NEW YORK</city>
</address_spec>
<names count="1">
<name addr_no="1" role="publisher" seq_no="1">
<display_name>ELSEVIER SCIENCE INC</display_name>
<full_name>ELSEVIER SCIENCE INC</full_name>
</name>
</names>
</publisher>
</publishers>
</summary>
</static_data>
</REC>
</records>
WOS:000310438600004
1662-1663
泌尿外科杂志
泌尿学杂志
尤罗。
尤罗
尤罗
什么东西
无名氏
无名氏
多伊,约翰
约翰
雌鹿
编辑材料
美国纽约州纽约市公园大道南360号,邮编:10010-1710
纽约
爱思唯尔科学公司
爱思唯尔科学公司
我做了两个假设:1)有早期的重复,2)你可以用部分文档做一些有意义的事情
让我们假设您可以移动某种级别的嵌套,然后多次处理文档,每次“处理”文档时都会删除工作级别的节点。这意味着在任何给定的时间,只有一个工作子树在内存中
下面是一段有效的代码片段:
package bigparse;
import static javax.xml.stream.XMLStreamConstants.CHARACTERS;
import static javax.xml.stream.XMLStreamConstants.END_DOCUMENT;
import static javax.xml.stream.XMLStreamConstants.END_ELEMENT;
import static javax.xml.stream.XMLStreamConstants.START_DOCUMENT;
import static javax.xml.stream.XMLStreamConstants.START_ELEMENT;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.StringWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
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 org.w3c.dom.Document;
import org.w3c.dom.Element;
public class BigParse {
public static void main(String... args) {
XMLInputFactory factory = XMLInputFactory.newInstance();
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
try {
XMLStreamReader streamReader = factory.createXMLStreamReader(new FileReader("src/main/resources/test.xml"));
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.newDocument();
Element rootElement = null;
Element currentElement = null;
int branchLevel = 0;
int maxBranchLevel = 1;
while (streamReader.hasNext()) {
int event = streamReader.next();
switch (event) {
case START_DOCUMENT:
continue;
case START_ELEMENT:
if (branchLevel < maxBranchLevel) {
Element workingElement = readElementOnly(streamReader, document);
if (rootElement == null) {
document.appendChild(workingElement);
rootElement = document.getDocumentElement();
currentElement = rootElement;
} else {
currentElement.appendChild(workingElement);
currentElement = workingElement;
}
branchLevel++;
} else {
workingLoop(streamReader, document, currentElement);
}
continue;
case CHARACTERS:
currentElement.setTextContent(streamReader.getText());
continue;
case END_ELEMENT:
if (currentElement != rootElement) {
currentElement = (Element) currentElement.getParentNode();
branchLevel--;
}
continue;
case END_DOCUMENT:
break;
}
}
} catch (ParserConfigurationException
| FileNotFoundException
| XMLStreamException e) {
throw new RuntimeException(e);
}
}
private static Element readElementOnly(XMLStreamReader streamReader, Document document) {
Element workingElement = document.createElement(streamReader.getLocalName());
for (int attributeIndex = 0; attributeIndex < streamReader.getAttributeCount(); attributeIndex++) {
workingElement.setAttribute(
streamReader.getAttributeLocalName(attributeIndex),
streamReader.getAttributeValue(attributeIndex));
}
return workingElement;
}
private static void workingLoop(final XMLStreamReader streamReader, final Document document, final Element fragmentRoot)
throws XMLStreamException {
Element startElement = readElementOnly(streamReader, document);
fragmentRoot.appendChild(startElement);
Element currentElement = startElement;
while (streamReader.hasNext()) {
int event = streamReader.next();
switch (event) {
case START_DOCUMENT:
continue;
case START_ELEMENT:
Element workingElement = readElementOnly(streamReader, document);
currentElement.appendChild(workingElement);
currentElement = workingElement;
continue;
case CHARACTERS:
currentElement.setTextContent(streamReader.getText());
continue;
case END_ELEMENT:
if (currentElement != startElement) {
currentElement = (Element) currentElement.getParentNode();
continue;
} else {
handleDocument(document, startElement);
fragmentRoot.removeChild(startElement);
startElement = null;
return;
}
}
}
}
// THIS FUNCTION DOES SOMETHING MEANINFUL
private static void handleDocument(Document document, Element startElement) {
System.out.println(stringify(document));
}
private static String stringify(Document document) {
try {
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
StreamResult result = new StreamResult(new StringWriter());
DOMSource source = new DOMSource(document);
transformer.transform(source, result);
String xmlString = result.getWriter().toString();
return xmlString;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
packagebigparse;
导入静态javax.xml.stream.XMLStreamConstants.CHARACTERS;
导入静态javax.xml.stream.XMLStreamConstants.END_文档;
导入静态javax.xml.stream.XMLStreamConstants.END_元素;
导入静态javax.xml.stream.XMLStreamConstants.START_文档;
导入静态javax.xml.stream.XMLStreamConstants.START_元素;
导入java.io.FileNotFoundException;
导入java.io.FileReader;
导入java.io.StringWriter;
导入javax.xml.parsers.DocumentBuilder;
导入javax.xml.parsers.DocumentBuilderFactory;
导入javax.xml.parsers.parserConfiguration异常;
导入javax.xml.stream.XMLInputFactory;
导入javax.xml.stream.XMLStreamException;
导入javax.xml.stream.XMLStreamReader;
导入javax.xml.transform.OutputKeys;
导入javax.xml.transform.Transformer;
导入javax.xml.transform.TransformerFactory;
导入javax.xml.transform.dom.DOMSource;
导入javax.xml.transform.stream.StreamResult;
导入org.w3c.dom.Document;
导入org.w3c.dom.Element;
公共类BigParse{
公共静态void main(字符串…参数){
XMLInputFactory=XMLInputFactory.newInstance();
DocumentBuilderFactory DocumentBuilderFactory=DocumentBuilderFactory.newInstance();
试一试{
XMLStreamReader=factory.createXMLStreamReader(新文件阅读器(“src/main/resources/test.xml”);
DocumentBuilder DocumentBuilder=documentBuilderFactory.newDocumentBuilder();
Document Document=documentBuilder.newDocument();
元素rootElement=null;
元素currentElement=null;
int branchLevel=0;
int maxBranchLevel=1;
while(streamReader.hasNext()){
int event=streamReader.next();
开关(事件){
案例启动文件:
继续;
案例开始元素:
if(branchLevel<xsl:template name="main">
<xsl:stream href="bigInput.xml">
<xsl:for-each select="copy-of(/records/REC)">
<!-- process one record -->
</xsl:for-each>
</xsl:stream>
</xsl:template>