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问题描述

我正在尝试测量StAX和DOM创建两个相同文档所需的时间。我不知道为什么DOM在创建XML时更快。也许我的StAX作家的代码不是很好。
所以这里是
StAX(更长的代码)

  public static final int pocet = 100000; 

try {

String encoding =UTF-8;
XMLOutputFactory f = XMLOutputFactory.newInstance();
XMLStreamWriter w = f.createXMLStreamWriter(
new FileOutputStream(subor),
encoding);
w.writeStartDocument(encoding,1.0);
w.writeCharacters(\r\\\
);
w.writeStartElement(Noviny); (int i = 1; i< = pocet; i ++){
w.writeCharacters(\r\\\
);

w.writeStartElement(Autor);
w.writeCharacters(\r\\\
);
w.writeStartElement(Id);
String ID = Integer.toString(i);
w.writeCharacters(ID);
w.writeEndElement();
w.writeCharacters(\r\\\
);
w.writeStartElement(Meno);
w.writeCharacters(Autor+ i);
w.writeEndElement();
w.writeCharacters(\r\\\
);
w.writeStartElement(Email);
w.writeCharacters(Autor+ i +@ email.com);
w.writeEndElement();
w.writeCharacters(\r\\\
);
w.writeStartElement(Tel_cislo);
w.writeAttribute(typ,pevna);
w.writeCharacters(+ 4219);
w.writeEndElement();
w.writeCharacters(\r\\\
);
w.writeStartElement(plat);

w.writeCharacters(5000);
w.writeEndElement();
w.writeCharacters(\r\\\
);
w.writeEndElement();
w.writeCharacters(\r\\\
);



}
w.writeCharacters(\r\\\
);
w.writeEndElement();
w.writeCharacters(\r\\\
);
w.writeEndDocument();
w.close();



}
catch(异常e){
e.printStackTrace();
}

DOM

  int pocet = 1500000; 
try {
DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = dfactory.newDocumentBuilder();
DOMImplementation domImpl = builder.getDOMImplementation();
文档文档= domImpl.createDocument(null,Noviny,null);
Node noviny = document.getDocumentElement(); (int i = 0; i< pocet; i ++){
元素autor = document.createElement(autor);

元素meno = document.createElement(meno);
元素id = document.createElement(id);
元素email = document.createElement(email);
元素tel = document.createElement(tel_cislo);
元素plat = document.createElement(plat);
文本textid = document.createTextNode(+ i);
文本textmeno = document.createTextNode(Autor+ i);
文本textemail = document.createTextNode([email protected]);
Text texttel = document.createTextNode(65456465465);
文本textplat = document.createTextNode(200);
noviny.appendChild(autor);
autor.appendChild(id);
id.appendChild(textid);
autor.appendChild(meno);
meno.appendChild(textmeno);
autor.appendChild(email);
email.appendChild(textemail);
autor.appendChild(tel);
tel.appendChild(texttel);
autor.appendChild(plat);
plat.appendChild(textplat);
}
TransformerFactory factory = TransformerFactory.newInstance();
变压器变压器= factory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT,yes);
transformer.setOutputProperty(OutputKeys.ENCODING,UTF-8);
transformer.transform(new DOMSource(document),new StreamResult(new File(subor)));

我知道StAX在阅读文档时速度更快,但我不能解释这一点。除了我对StAX有不错的代码



谢谢

解决方案

在这里添加BufferedOuputStream

  XMLStreamWriter w = f.createXMLStreamWriter(new BufferedOutputStream(new FileOutputStream(subor)),UTF-8) ; 

现在测试速度,你会看到StAX至少快2倍。 b $ b

i was trying to measure time needed for StAX and DOM to create two same documents. I dont know why DOM is faster in creating XML. Maybe my code for StAX writer is not very good.so here it isStAX(longer code)

  public static final int pocet =100000;

try {

  String encoding = "UTF-8";
  XMLOutputFactory f = XMLOutputFactory.newInstance();
  XMLStreamWriter w = f.createXMLStreamWriter(
                      new FileOutputStream(subor),
                      encoding);
  w.writeStartDocument(encoding, "1.0");
  w.writeCharacters("\r\n");
  w.writeStartElement("Noviny");        
  for (int i = 1;  i <= pocet;  i++) {
    w.writeCharacters("\r\n  ");
    w.writeStartElement("Autor");
    w.writeCharacters("\r\n  ");
    w.writeStartElement("Id"); 
    String ID = Integer.toString(i);
    w.writeCharacters(ID);
    w.writeEndElement();
    w.writeCharacters("\r\n  ");
    w.writeStartElement("Meno");
    w.writeCharacters("Autor"+i);
    w.writeEndElement();
    w.writeCharacters("\r\n  ");
    w.writeStartElement("Email");
    w.writeCharacters("Autor"+i+"@email.com");
    w.writeEndElement();
    w.writeCharacters("\r\n  ");
    w.writeStartElement("Tel_cislo");
    w.writeAttribute("typ", "pevna");
    w.writeCharacters("+4219");
    w.writeEndElement();
    w.writeCharacters("\r\n  ");
    w.writeStartElement("plat");

    w.writeCharacters("5000");
    w.writeEndElement();
    w.writeCharacters("\r\n  ");        
    w.writeEndElement(); 
    w.writeCharacters("\r\n");



  }
  w.writeCharacters("\r\n");
  w.writeEndElement();        
  w.writeCharacters("\r\n");
  w.writeEndDocument();
  w.close(); 



}
catch (Exception e) {
  e.printStackTrace();
}

DOM

       int pocet =1500000;
try {
 DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
 DocumentBuilder builder = dfactory.newDocumentBuilder();
 DOMImplementation domImpl = builder.getDOMImplementation();
 Document document = domImpl.createDocument(null, "Noviny", null);
 Node noviny = document.getDocumentElement();
 for(int i = 0; i<pocet ; i++) {
 Element autor = document.createElement("autor");
 Element meno = document.createElement("meno");
 Element id = document.createElement("id");
 Element email = document.createElement("email");
 Element tel = document.createElement("tel_cislo");
  Element plat = document.createElement("plat");
 Text textid = document.createTextNode(""+i);
 Text textmeno = document.createTextNode("Autor"+i);
 Text textemail = document.createTextNode("[email protected]");
 Text texttel = document.createTextNode("65456465465");
 Text textplat = document.createTextNode("200");
   noviny.appendChild(autor);
    autor.appendChild(id);
        id.appendChild(textid);
    autor.appendChild(meno);
        meno.appendChild(textmeno);
    autor.appendChild(email);
        email.appendChild(textemail);
    autor.appendChild(tel);
        tel.appendChild(texttel);
    autor.appendChild(plat);
        plat.appendChild(textplat);
     }  
  TransformerFactory factory = TransformerFactory.newInstance();
  Transformer transformer = factory.newTransformer();
  transformer.setOutputProperty(OutputKeys.INDENT, "yes"); 
  transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
  transformer.transform(new DOMSource(document),new StreamResult(new File(subor)));

i know that StAX is way faster in reading document, but i can´t explain this. Except that i have pretty bad code for StAX

thanks

解决方案

Add BufferedOuputStream here

XMLStreamWriter w = f.createXMLStreamWriter(new BufferedOutputStream(new FileOutputStream(subor)), "UTF-8");

now test the speed and you will see that StAX is at least 2 times faster

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09-25 11:32