如何在Java中讀取解析檔案呢？下面小編為大家整理了java讀取解析xml檔案例項，希望能幫到大家！
讀取本地的xml檔案，通過DOM進行解析，DOM解析的特點就是把整個xml檔案裝載入記憶體中，形成一顆DOM樹形結構，樹結構是方便遍歷和和操縱。
DOM解析的特性就是讀取xml檔案轉換為 dom樹形結構，通過節點進行遍歷。
這是W3c關於節點的概念
如果xml中包含有大量的資料，由於dom一次性把xml裝入記憶體中的特性，所以dom不適合於包含大量資料的'xml解析。當包含有大量xml的時候，用SAX進行解析比較節省記憶體。
下面是一個運用DOM進行解析xml檔案的例子：
xml檔案結構如下：
<"1.0" encoding="ISO-8859-1">Giada De Laurentiis200530.00J K. Rowling200529.99James McGovern200349.99Erik T. Ray200339.95
建立解析xml的類如下：
package ;import ;import mentBuilder;import mentBuilderFactory;import ment;import ent;import ;import List;public class ReadXmlFile { public static void main(String[] args) { try{ File xmlFile = new File("src/resource/"); DocumentBuilderFactory builderFactory = nstance(); DocumentBuilder builder = ocumentBuilder(); Document doc = e(xmlFile); ocumentElement()alize(); tln("Root element: "+ocumentElement()odeName()); NodeList nList = lementsByTagName("book"); for(int i = 0 ; i<ength();i++){ Node node = (i); tln("Node name: "+ odeName()); Element ele = (Element)node; tln("----------------------------"); if(odeType() == ENT_NODE){ tln("book category: "+ ttribute("category")); tln("title name: "+ lementsByTagName("title")(0)extContent()); tln("author name: "+lementsByTagName("author")(0)extContent()); tln("year :"+lementsByTagName("year")(0)extContent()); tln("price : "+lementsByTagName("price")(0)extContent()); tln("-------------------------"); } }
解析結果：
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獲得對應的值，
下面利用迴圈節點的方式輸出：
迴圈節點輸出方式的程式碼如下：
package ;import ;import mentBuilder;import mentBuilderFactory;import ment;import dNodeMap;import ;import List;public class ReadXmlFile2 { public static void main(String[] args) { try{ File xmlFile = new File("src/resource/"); DocumentBuilderFactory builderFactory = nstance(); DocumentBuilder builder = ocumentBuilder(); Document doc = e(xmlFile); ocumentElement()alize(); tln("Root element: "+ocumentElement()odeName()); if(hildNodes()){ printNode(hildNodes()); } }catch(Exception e){ tStackTrace(); } } public static void printNode(NodeList nodeList){ tln("------------------------"); // tln(ength()); for(int i = 0; i<ength(); i++){ Node node = (Node)(i); if(odeType() == ENT_NODE){ tln("node name: "+odeName()); tln("node value: "+extContent()); if(ttributes()){ NamedNodeMap nodeMap = ttributes(); for(int j = 0; j < ength() ; j++){ Node nodenew = (j); tln("node name "+odeName()); tln("node value "+odeValue()); } } if(hildNodes()){ printNode(hildNodes()); } } } }}
輸出結果如下：
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------------------------
關於節點的問題：
Giada De Laurentiis200530.00
對於 book應用：hildNodes() 得到一個NodeList其中NodeList的長度為9
9個節點分別如下：
title節點
lang節點
Everyday節點
author節點
Giada De Laurentiis節點
year節點
2005節點
price節點
30.00節點
