vtd的優勢是綜合了dom和sax的二者的優勢
解析快,佔內存少,快速查找,增量更新。
測試的xml文件大小分別是003K,010K,184K,744K
VTD用com.ximpleware.vtd-xml, version is 2.13
SAX用sax.sax, version is 2.0.1
測試功能只實現了 解析,並沒有向POJO去映射,困爲這種POJO映射行爲是統一的,沒什麼區別,我們單單測試 xml parsor 性能。
SumTimeMS表示解析100次的總時間,單位是毫秒
============================================
xmlSizeKB, vtdSumTimeMS,saxSumTimeMS
003K, 137MS, 192MS010K, 189MS, 237MS
184K, 454MS, 402MS
744K, 606MS, 587MS
============================================
從測試結果來看
如果文件比較小,大概010K左右,vtd性能可以提高16%左右。
如果文件比較大,大概100K左右,vtd性能開始慢了,沒有sax性能好。
測試數據和測試方法,應該沒什麼問題
vtd號稱The World Fastest XML Parsor,看來,也不怎麼樣。
vtd的優勢是綜合了dom和sax的所有好處,解析快,佔內存少,可以快速查找,可以增量更新。
package com.jelly;
import com.ximpleware.VTDGen;
import com.ximpleware.VTDNav;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import java.io.BufferedInputStream;
import java.io.InputStream;
public class XmlPerf {
private static final String xml = "/myDoc744.xml";
public static void main(String[] args) throws Exception {
long sum = 0;
for(int i = 0; i < 100; i++){
long s = System.currentTimeMillis();
// vtdTest();
saxTest();
long e = System.currentTimeMillis();
sum += (e - s);
}
double sumD = (double)sum;
System.out.println("sumMS=" + sumD + ", avgMS=" + sumD/10D);
}
private static void vtdTest() throws Exception {
InputStream is = XmlPerf.class.getResourceAsStream(xml);
BufferedInputStream bis = new BufferedInputStream(is);
byte[] b = new byte[is.available()];
bis.read(b);
bis.close();
VTDGen vg = new VTDGen();
vg.setDoc(b);
vg.parse(false);
VTDNav vn = vg.getNav();
int size = vn.getTokenCount();
for (int i = 0; i < size; i++) {
vn.toString(i).trim();
}
vg.clear();
}
private static void saxTest() throws Exception {
DefaultHandler handler = new DefaultHandler(){
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
// System.out.println("qName=" + qName);
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
// System.out.println("qName=" + qName);
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
// System.out.println("content>>>" + new String(ByteBuffer.wrap(ch, start, length)));
}
};
InputStream is = XmlPerf.class.getResourceAsStream(xml);
BufferedInputStream bis = new BufferedInputStream(is);
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
saxParser.parse(bis, handler);
bis.close();
}
}