我继承了一个使用简单文本文件保存文档的数据存储。加载XML非常慢
文档具有一些属性(日期,标题和文本),并且这些文件以文件名进行编码:< date> - < title> .txt,文件正文为文本。
然而实际上系统中的文档有更多的属性,甚至更多的是建议添加。
切换到XML格式似乎是合乎逻辑的,我已经这样做了,每个文档现在都编码在它自己的XML文件中。
但是,从XML读取文件现在很慢! (其中.txt格式的2000篇文章花费了几秒钟,现在2000篇.xml格式的文章花费了10分钟以上)。
我正在使用DOM解析器,并且在我发现读取速度有多慢之后,我切换到了SAX解析器,但它仍然一样慢(好,更快,但仍然10分钟)。
XML是否慢,还是我做一些奇怪的事情?任何想法将不胜感激。
该系统是用JavaSE 1.6编写的。 解析器创建这样的:
/*
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
*/
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser;
try {
saxParser = factory.newSAXParser();
ArticleSaxHandler handler = new ArticleSaxHandler();
saxParser.parse(is, handler);
return handler.getArticle();
} catch (ParserConfigurationException e) {
throw new IOException(e);
} catch (SAXException e) {
throw new IOException(e);
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
logger.error(e);
}
}
}
}
private class ArticleSaxHandler extends DefaultHandler {
private URI uri = null;
private String source = null;
private String author = null;
private DateTime articleDatetime = null;
private DateTime processedDatetime = null;
private String title = null;
private String text = null;
private ArticleElement currentElement;
private final StringBuilder builder = new StringBuilder();
public Article getArticle() {
return new Article(uri, source, author, articleDatetime, processedDatetime, title, text);
}
/** Receive notification of the start of an element. */
public void startElement(String uri, String localName, String qName, Attributes attributes) {
if (builder.length() != 0) {
throw new RuntimeException(new SAXParseException(currentElement + " was not finished before " + qName + " was started", null));
}
currentElement = ArticleElement.getElement(qName);
}
public void endElement(String uri, String localName, String qName) {
final String elementText = builder.toString();
builder.delete(0, builder.length());
if (currentElement == null) {
return;
}
switch (currentElement) {
case ARTICLE:
break;
case URI:
try {
this.uri = new URI(elementText);
} catch (URISyntaxException e) {
throw new RuntimeException(e);
}
break;
case SOURCE:
source = elementText;
break;
case AUTHOR:
author = elementText;
break;
case ARTICLE_DATE_TIME:
articleDatetime = getDateTimeFormatter().parseDateTime(elementText);
break;
case PROCESSED_DATE_TIME:
processedDatetime = getDateTimeFormatter().parseDateTime(elementText);
break;
case TITLE:
title = elementText;
break;
case TEXT:
this.text = elementText;
break;
default:
throw new IllegalStateException("Unexpected ArticleElement: " + currentElement);
}
currentElement = null;
}
/** Receive notification of character data inside an element. */
public void characters(char[] ch, int start, int length) {
builder.append(ch, start, length);
}
public void error(SAXParseException e) {
fatalError(e);
}
public void fatalError(SAXParseException e) {
logger.error("currentElement: " + currentElement + " ||builder: " + builder.toString() + "\n\n" + e.getMessage(), e);
}
}
private enum ArticleElement {
ARTICLE(ARTICLE_ELEMENT_NAME), URI(URI_ELEMENT_NAME), SOURCE(SOURCE_ELEMENT_NAME), AUTHOR(AUTHOR_ELEMENT_NAME), ARTICLE_DATE_TIME(
ARTICLE_DATETIME_ELEMENT_NAME), PROCESSED_DATE_TIME(PROCESSED_DATETIME_ELEMENT_NAME), TITLE(TITLE_ELEMENT_NAME), TEXT(TEXT_ELEMENT_NAME);
private String name;
private ArticleElement(String name) {
this.name = name;
}
public static ArticleElement getElement(String qName) {
for (ArticleElement element : ArticleElement.values()) {
if (element.name.equals(qName)) {
return element;
}
}
return null;
}
}
没有XML是不是慢,本身。抓住一个分析器,并检查哪部分是缓慢的。 – 2010-08-19 11:04:40
除非您发布代码示例 – 2010-08-19 11:04:43
2000年的文章文件有多大,否则无法知道您是否在“做一些奇怪的事情”?你有多少内存给你的虚拟机?什么是CPU使用率? – 2010-08-19 11:06:34