xml解析方式

1.sax

流解析，character函数可能执行多次，数据被截断，用StringBuffer在character方法中拼接字符串，在end方法中取数据才不会断，遇到一个问题，之前这么写的，在windows执行没有问题，但换到linux后有时候character被多次执行

/**
*
*/
package com.jiudao.www.util;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
* @author lenovo0-
*
*/
public class SaxParseService extends DefaultHandler{
private List<String> elementsList = null;
private String datalogelement = null;
private String preTag = null;//作用是记录解析时的上一个节点名称

public List<String> getElements(InputStream xmlStream) throws Exception{
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
SaxParseService handler = new SaxParseService();
parser.parse(xmlStream, handler);
return handler.getDatalogElements();
}

public List<String> getDatalogElements(){
return elementsList;
}

@Override
public void startDocument() throws SAXException {
elementsList = new ArrayList<String>();
}

@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

preTag = qName;//将正在解析的节点名称赋给preTag
}

@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
preTag = null;
}

@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if(preTag!=null){
String content = new String(ch,start,length);
if(preTag.equals("datalogelement")){
elementsList.add(content);
//System.out.println("content:"+content);
}
}
//
}

}

修改后的代码

/**
*
*/
package com.jiudao.www.util;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
* @author lenovo0-
*
*/
public class SaxParseService extends DefaultHandler{
private List<String> elementsList = null;
private String preTag = null;//作用是记录解析时的上一个节点名称
private StringBuilder sb;
public List<String> getElements(InputStream xmlStream) throws Exception{
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
SaxParseService handler = new SaxParseService();
parser.parse(xmlStream, handler);
return handler.getDatalogElements();
}

public List<String> getDatalogElements(){
return elementsList;
}

@Override
public void startDocument() throws SAXException {
elementsList = new ArrayList<String>();
sb = new StringBuilder();
}

@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

preTag = qName;//将正在解析的节点名称赋给preTag
}

@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if(qName.equals("datalogelement")){
elementsList.add(sb.toString());
}
preTag = null;
}

@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if(preTag!=null){
String content = new String(ch,start,length);
//                if(preTag.equals("datalogelement")){
//                    elementsList.add(content);
//                    //System.out.println("content:"+content);
//                }
sb.append(content);
}

}

}

2.dom

把文件加载到内存中，不适用于大文件