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java解析xml之sax解析xml示例分享

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SAX基于事件的解析,解析器在一次读取XML文件中根据读取的数据产生相应的事件,由应用程序实现相应的事件处理逻辑,即它是一种“推”的解析方式;这种解析方法速度快、占用内存少,但是它需要应用程序自己处理解析器的状态,实现起来会比较麻烦

复制代码 代码如下:

package com.test;

import java.io.File;
import java.io.FileInputStream;
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;

public class SaxXML {

    public static void main(String[] args) {
        File file = new File("e:/People.xml");
        try {
            SAXParserFactory spf = SAXParserFactory.newInstance();
            SAXParser parser = spf.newSAXParser();
            SaxHandler handler = new SaxHandler("People");
            parser.parse(new FileInputStream(file), handler);

            List<People> peopleList = handler.getPeoples();
            for(People people : peopleList){
                System.out.println(people.getId()+"\t"+people.getName()+"\t"+people.getEnglishName()+"\t"+people.getAge());
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

class SaxHandler extends DefaultHandler {
    private List<People> peoples = null;
    private People people;
    private String currentTag = null;
    private String currentValue = null;
    private String nodeName = null;

    public List<People> getPeoples() {
        return peoples;
    }

    public SaxHandler(String nodeName) {
        this.nodeName = nodeName;
    }

    @Override
    public void startDocument() throws SAXException {
        // TODO 当读到一个开始标签的时候,会触发这个方法
        super.startDocument();

        peoples = new ArrayList<People>();
    }

    @Override
    public void endDocument() throws SAXException {
        // TODO 自动生成的方法存根
        super.endDocument();
    }

    @Override
    public void startElement(String uri, String localName, String name,
            Attributes attributes) throws SAXException {
        // TODO 当遇到文档的开头的时候,调用这个方法
        super.startElement(uri, localName, name, attributes);

        if (name.equals(nodeName)) {
            people = new People();
        }
        if (attributes != null && people != null) {
            for (int i = 0; i < attributes.getLength(); i++) {
                if(attributes.getQName(i).equals("id")){
                    people.setId(attributes.getValue(i));
                }
                else if(attributes.getQName(i).equals("en")){
                    people.setEnglishName(attributes.getValue(i));
                }
            }
        }
        currentTag = name;
    }

    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        // TODO 这个方法用来处理在XML文件中读到的内容
        super.characters(ch, start, length);

        if (currentTag != null && people != null) {
            currentValue = new String(ch, start, length);
            if (currentValue != null && !currentValue.trim().equals("") && !currentValue.trim().equals("\n")) {
                if(currentTag.equals("Name")){
                    people.setName(currentValue);
                }
                else if(currentTag.equals("Age")){
                    people.setAge(currentValue);
                }
            }
        }
        currentTag = null;
        currentValue = null;
    }

    @Override
    public void endElement(String uri, String localName, String name)
            throws SAXException {
        // TODO 在遇到结束标签的时候,调用这个方法
        super.endElement(uri, localName, name);

        if (name.equals(nodeName)) {
            peoples.add(people);
        }
    }

}

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