dom

/* * Copyright (C) 2009 Teleca Poland Sp. z o.o. <android@teleca.com> * * Licensed under the Apache License,Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing,software * distributed under the License is distributed on an "AS IS" BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */

package com.android.yunshi.util;

import java.io.IOException;
import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
//xml的转换解析器
/** * @author Lukasz Wisniewski */
public class XMLUtil {

    /** * singleton */
    private static DocumentBuilderFactory documentBuilderFactory = null;

    /** * DocumentBuilderFactory instance (lazy initialization) * * @return */
    private static DocumentBuilderFactory getDocumentBuilderFactory(){
        if(documentBuilderFactory == null){
            documentBuilderFactory = DocumentBuilderFactory.newInstance();
        }
        return documentBuilderFactory;
    }

    /** * DocumentBuilder instance * * @return */
    private static DocumentBuilder getDocumentBuilder(){
        try {
            return getDocumentBuilderFactory().newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            return null;
        }
    }

    /** * Converts String containing XML code to Document * * @param xmlString * @return <code>Document</code> interface */
    public static Document stringToDocument(String xmlString){//字符串到xml的解析
        if(xmlString == null)
            return null;

        DocumentBuilder documentBuilder = getDocumentBuilder();
        InputSource inputSource = new InputSource(new StringReader(xmlString));
        try {
            return documentBuilder.parse(inputSource);
        } catch (SAXException e) {
            e.printStackTrace();
            return null;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

}

package com.android.yunshi.fun;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;


import com.android.yunshi.util.XMLUtil;

//解析运势字符串，并封装为实体类
public class YunshiFunctions {
    private static Document document = null;
    private static Element root = null;

    public static Map<String,String> ResolveResultString(String xmlString,String rootstring) {
        // TODO Auto-generated method stub
        Map<String,String> entity = new HashMap();
        NodeList nodes;
        int size;

        document = XMLUtil.stringToDocument(xmlString);
        if (document == null) {
            return null;
        }
        root = document.getDocumentElement();
        nodes = root.getElementsByTagName(rootstring);
        Element TableName = (Element) nodes.item(0);
        nodes = TableName.getChildNodes();
        size = nodes.getLength();
        for (int i = 0; i < size; i++) {
            Node node = (Node) nodes.item(i);
            NodeList nodes2 = node.getChildNodes();
            int size2 = nodes2.getLength();
            for (int j = 0; j < size2; j++) {
                Node node2 = (Node) nodes2.item(j);
                if (node2.getNodeType() == Node.ELEMENT_NODE) {
                    Element childNode = (Element) node2;
                    entity.put(childNode.getNodeName(),childNode.getTextContent());
                }
            }
        }

        return entity;
    }

    public static String ResolveResultStringToString(String xmlString,String rootstring) {
        // TODO Auto-generated method stub
        String entity;
        NodeList nodes;
        int size;

        document = XMLUtil.stringToDocument(xmlString);
        if (document == null) {
            return null;
        }
        root = document.getDocumentElement();
        nodes = root.getChildNodes();
        entity = nodes.item(0).getTextContent();
        return entity;
    }

    public static List<Map<String,String>> ResolveResultStringToList(
            String xmlString,String rootstring) {
        List<Map<String,String>> list = new ArrayList<Map<String,String>>();

        NodeList nodes;
        int size;

        document = XMLUtil.stringToDocument(xmlString);
        if (document == null) {
            return null;
        }
        root = document.getDocumentElement();
        nodes = root.getElementsByTagName(rootstring);
        Element TableName = (Element) nodes.item(0);
        nodes = TableName.getChildNodes();
        size = nodes.getLength();
        for (int i = 0; i < size; i++) {
            Node node = (Node) nodes.item(i);
            NodeList nodes2 = node.getChildNodes();
            int size2 = nodes2.getLength();
            Map<String,String> entity = new HashMap();
            for (int j = 0; j < size2; j++) {
                Node node2 = (Node) nodes2.item(j);
                if (node2.getNodeType() == Node.ELEMENT_NODE) {
                    Element childNode = (Element) node2;
                    entity.put(childNode.getNodeName(),childNode.getTextContent());
                }
            }
            list.add(entity);
        }

        return list;

    }
}

SAX

JAVA 解析 XML 通常有两种方式，DOM 和 SAX。即java中的JDK已经内置了SAX和DOM解析的相关包，因此这里不用导入第三方的jar包。 SAX的全称是Simple APIs for XML，也即XML简单应用程序接口。与DOM不同，SAX提供的访问模式是一种顺序模式，这是一种快速读写XML数据的方式。当使用SAX分析器XML文档进行分析时，会触发一系列事件，并激活相应的事件处理函数，应用程序通过这些事件处理函数实现对XML文档的访问，因而SAX接口也被称作事件驱动接口。
下面是sax解析xml 的示例：

1、要解析的person.xml文件

2、获取服务器端xml文件输入流的工具类HttpUtil.java

public class HttpUtil
{
    public static InputStream getXML(String path)
    {
        InputStream in = null;
        try
        {
            URL url = new URL(path);
            if (url != null)
            {
                HttpURLConnection httpConn = (HttpURLConnection) url
                        .openConnection();
                httpConn.setConnectTimeout(3000);
                httpConn.setDoInput(true);
                httpConn.setRequestMethod("GET");
                int code = httpConn.getResponseCode();
                if (code == 200)
                {
                    in = httpConn.getInputStream();
                }
            }
        }
        catch (Exception e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return in;
    }
}

3.处理XML文件的核心类，该类一定要继承DefaultHandler 并覆盖相应的方法

package com.sax.handler;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.jar.Attributes.Name;

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

public class MyHandler extends DefaultHandler {

    private HashMap map = null;// 存储单个解析的完整对象
    private List> list = null;// 存储所有的解析对象
    private String currentTag = null;// 正在解析的元素的标签
    private String currentValue = null;// 解析当前元素的值
    private String nodeName = null;// 解析当前的节点名称

    public MyHandler(String nodeName) {
        // TODO Auto-generated constructor stub
        this.nodeName = nodeName;
    }

    public List> getList() {
        return list;
    }

    @Override
    public void startDocument() throws SAXException {
        // TODO Auto-generated method stub
        // 当读到第一个开始标签的时候，会触发这个方法
        list = new ArrayList>();
    }

    @Override
    public void startElement(String uri,String localName,String qName,Attributes attributes) throws SAXException {
        // 当遇到文档的开头的时候，调用这个方法
        if (qName.equals(nodeName)) {
            map = new HashMap();
        }
        if (attributes != null && map != null) {
            for (int i = 0; i < attributes.getLength(); i++) {
                map.put(attributes.getQName(i),attributes.getValue(i));
            }
        }
        currentTag = qName;
    }

    @Override
    public void characters(char[] ch,int start,int length)
            throws SAXException {
        // TODO Auto-generated method stub
        // 这个方法是用来处理xml文件所读取到的内容
        if (currentTag != null && map != null) {
            currentValue = new String(ch,start,length);
            if (currentValue != null && !currentValue.trim().equals("")
                    && !currentValue.trim().equals("\n")) {
                map.put(currentTag,currentValue);
            }
        }
        currentTag = null;// 把当前的节点的对应的值和标签设置为空
        currentValue = null;

    }

    @Override
    public void endElement(String uri,String qName)
            throws SAXException {
        // TODO Auto-generated method stub
        // 遇到结束标记的时候，会调用这个方法
        if (qName.equals(nodeName)) {
            list.add(map);
            map = null;
        }
        super.endElement(uri,localName,qName);
    }
}

4、SAX解析的业务逻辑层

public class SaxService
{
    public SaxService()
    {
        // TODO Auto-generated constructor stub
    }

    public static List> readXML(InputStream in,String nodeName)
    {

        try
        {//获取SAx的实例工厂，并获取解析实例
            SAXParserFactory spf = SAXParserFactory.newInstance();
            SAXParser parser = spf.newSAXParser();
            MyHandler handler = new MyHandler(nodeName);
            parser.parse(in,handler);// 开始解析XML文件
            in.close();
            return handler.getList();
        }
        catch (ParserConfigurationException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        catch (SAXException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        catch (IOException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;

    }
}

5、测试类

public class TestSax
{
    public static void main(String[] args)
    {
        //要访问的xml文件的服务器地址
        String url = "http://localhost:8081/jspchat/person.xml";
        //获取服务器端xml文件的输入流
        InputStream in = HttpUtil.getXML(url);
        //调用业务逻辑层访问xml文件中元素为person的的节点
        List> list = SaxService.readXML(in,"person");
        for (HashMap map : list)
        {
            System.out.println(map.toString());
        }
    }
}