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java讀取解析xml文件實(shí)例

　　如何在Java中讀取解析文件呢？下面小編為大家整理了java讀取解析xml文件實(shí)例，希望能幫到大家！

　　讀取本地的xml文件，通過DOM進(jìn)行解析，DOM解析的特點(diǎn)就是把整個(gè)xml文件裝載入內(nèi)存中，形成一顆DOM樹形結(jié)構(gòu)，樹結(jié)構(gòu)是方便遍歷和和操縱。

　　DOM解析的特性就是讀取xml文件轉(zhuǎn)換為 dom樹形結(jié)構(gòu)，通過節(jié)點(diǎn)進(jìn)行遍歷。

　　這是W3c關(guān)于節(jié)點(diǎn)的概念

　　如果xml中包含有大量的數(shù)據(jù)，由于dom一次性把xml裝入內(nèi)存中的特性，所以dom不適合于包含大量數(shù)據(jù)的xml解析。當(dāng)包含有大量xml的時(shí)候，用SAX進(jìn)行解析比較節(jié)省內(nèi)存。

　　下面是一個(gè)運(yùn)用DOM進(jìn)行解析xml文件的例子：

　　xml文件結(jié)構(gòu)如下：

　　<"1.0" encoding="ISO-8859-1">Giada De Laurentiis200530.00J K. Rowling200529.99James McGovern200349.99Erik T. Ray200339.95

　　創(chuàng)建解析xml的類如下：

　　package xml.dom;import java.io.File;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import org.w3c.dom.Document;import org.w3c.dom.Element;import org.w3c.dom.Node;import org.w3c.dom.NodeList;public class ReadXmlFile { public static void main(String[] args) { try{ File xmlFile = new File("src/resource/book.xml"); DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = builderFactory.newDocumentBuilder(); Document doc = builder.parse(xmlFile); doc.getDocumentElement().normalize(); System.out.println("Root element: "+doc.getDocumentElement().getNodeName()); NodeList nList = doc.getElementsByTagName("book"); for(int i = 0 ; i<nList.getLength();i++){ Node node = nList.item(i); System.out.println("Node name: "+ node.getNodeName()); Element ele = (Element)node; System.out.println("----------------------------"); if(node.getNodeType() == Element.ELEMENT_NODE){ System.out.println("book category: "+ ele.getAttribute("category")); System.out.println("title name: "+ ele.getElementsByTagName("title").item(0).getTextContent()); System.out.println("author name: "+ele.getElementsByTagName("author").item(0).getTextContent()); System.out.println("year :"+ele.getElementsByTagName("year").item(0).getTextContent()); System.out.println("price : "+ele.getElementsByTagName("price").item(0).getTextContent()); System.out.println("-------------------------"); } }

　　解析結(jié)果：

　　Root element: bookstoreNode name: book----------------------------book category: cookingtitle name: Everyday Italianauthor name: Giada De Laurentiisyear :2005price : 30.00-------------------------Node name: book----------------------------book category: childrentitle name: Harry Potterauthor name: J K. Rowlingyear :2005price : 29.99-------------------------Node name: book----------------------------book category: webtitle name: XQuery Kick Startauthor name: James McGovernyear :2003price : 49.99-------------------------Node name: book----------------------------book category: webtitle name: Learning XMLauthor name: Erik T. Rayyear :2003price : 39.95-------------------------

　　以上是通過name獲得對應(yīng)的值，

　　下面利用循環(huán)節(jié)點(diǎn)的方式輸出：

　　循環(huán)節(jié)點(diǎn)輸出方式的代碼如下：

　　package xml.dom;import java.io.File;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import org.w3c.dom.Document;import org.w3c.dom.NamedNodeMap;import org.w3c.dom.Node;import org.w3c.dom.NodeList;public class ReadXmlFile2 { public static void main(String[] args) { try{ File xmlFile = new File("src/resource/book.xml"); DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = builderFactory.newDocumentBuilder(); Document doc = builder.parse(xmlFile); doc.getDocumentElement().normalize(); System.out.println("Root element: "+doc.getDocumentElement().getNodeName()); if(doc.hasChildNodes()){ printNode(doc.getChildNodes()); } }catch(Exception e){ e.printStackTrace(); } } public static void printNode(NodeList nodeList){ System.out.println("------------------------"); // System.out.println(nodeList.getLength()); for(int i = 0; i<nodeList.getLength(); i++){ Node node = (Node)nodeList.item(i); if(node.getNodeType() == Node.ELEMENT_NODE){ System.out.println("node name: "+node.getNodeName()); System.out.println("node value: "+node.getTextContent()); if(node.hasAttributes()){ NamedNodeMap nodeMap = node.getAttributes(); for(int j = 0; j < nodeMap.getLength() ; j++){ Node nodenew = nodeMap.item(j); System.out.println("node name "+nodenew.getNodeName()); System.out.println("node value "+nodenew.getNodeValue()); } } if(node.hasChildNodes()){ printNode(node.getChildNodes()); } } } }}

　　輸出結(jié)果如下：

　　Root element: bookstore------------------------node name: bookstorenode value: Everyday Italian Giada De Laurentiis 2005 30.00 Harry Potter J K. Rowling 2005 29.99 XQuery Kick Start James McGovern 2003 49.99 Learning XML Erik T. Ray 2003 39.95 ------------------------node name: booknode value: Everyday Italian Giada De Laurentiis 2005 30.00 node name categorynode value cooking------------------------node name: titlenode value: Everyday Italiannode name langnode value en------------------------node name: authornode value: Giada De Laurentiis------------------------node name: yearnode value: 2005------------------------node name: pricenode value: 30.00------------------------node name: booknode value: Harry Potter J K. Rowling 2005 29.99 node name categorynode value children------------------------node name: titlenode value: Harry Potternode name langnode value en------------------------node name: authornode value: J K. Rowling------------------------node name: yearnode value: 2005------------------------node name: pricenode value: 29.99------------------------node name: booknode value: XQuery Kick Start James McGovern 2003 49.99 node name categorynode value web------------------------node name: titlenode value: XQuery Kick Startnode name langnode value en------------------------node name: authornode value: James McGovern------------------------node name: yearnode value: 2003------------------------node name: pricenode value: 49.99------------------------node name: booknode value: Learning XML Erik T. Ray 2003 39.95 node name categorynode value webnode name covernode value paperback------------------------node name: titlenode value: Learning XMLnode name langnode value en------------------------node name: authornode value: Erik T. Ray------------------------node name: yearnode value: 2003------------------------node name: pricenode value: 39.95------------------------

　　關(guān)于節(jié)點(diǎn)的問題：

　　Giada De Laurentiis200530.00

　　對于 book應(yīng)用：doc.getChildNodes() 得到一個(gè)NodeList其中NodeList的長度為9

　　9個(gè)節(jié)點(diǎn)分別如下：

　　title節(jié)點(diǎn)

　　lang節(jié)點(diǎn)

　　Everyday節(jié)點(diǎn)

　　author節(jié)點(diǎn)

　　Giada De Laurentiis節(jié)點(diǎn)

　　year節(jié)點(diǎn)

　　2005節(jié)點(diǎn)

　　price節(jié)點(diǎn)