學習中發現兩個哥們寫的挺好的。轉過來方便以后使用。謝謝那倆哥們了。
http://wuhongyu.iteye.com/blog/361842 xml是一種廣為使用的可擴展標記語言,java中解析xml的方式有很多,最常用的像jdom、dom4j、sax等等。前兩天剛好有個程序需要解析xml,就學了下jdom,寫了個小例子,這里做個學習筆記。
要使用jdom解析xml文件,需要下載jdom的包,我使用的是jdom-1.1。解壓之后,將lib文件夾下的.jar文件以及build文件夾下的jdom.jar拷貝到工程文件夾下,然后就可以使用jdom操作xml文件了。
一、讀取xml文件
假設有這樣一個xml文件:
- <?xml version="1.0" encoding="UTF-8"?>
- <sys-config>
- <jdbc-info>
- <driver-class-name>oracle.jdbc.driver.OracleDriver</driver-class-name>
- <url>jdbc:oracle:thin:@localhost:1521:database</url>
- <user-name>why</user-name>
- <password>why</password>
- </jdbc-info>
- <provinces-info>
- <province id="hlj" name="黑龍江">
- <city id="harb">哈爾濱</city>
- <city id="nj">嫩江</city>
- </province>
- <province id="jl" name="吉林"></province>
- </provinces-info>
- </sys-config>
<?xml version="1.0" encoding="UTF-8"?>
<sys-config>
<jdbc-info>
<driver-class-name>oracle.jdbc.driver.OracleDriver</driver-class-name>
<url>jdbc:oracle:thin:@localhost:1521:database</url>
<user-name>why</user-name>
<password>why</password>
</jdbc-info>
<provinces-info>
<province id="hlj" name="黑龍江">
<city id="harb">哈爾濱</city>
<city id="nj">嫩江</city>
</province>
<province id="jl" name="吉林"></province>
</provinces-info>
</sys-config>
首先,用 org.jdom.input.SAXBuilder 這個類取得要操作的xml文件,會返回一個 org.jdom.Document 對象,這里需要做一下異常處理。然后,取得這個xml文件的根節點,org.jdom.Element 代表xml文件中的一個節點,取得跟節點后,便可以讀取xml文件中的信息。利用 org.jdom.xpath.XPath 可以取得xml中的任意制定的節點中的信息。
例如,要取得上面文件中的 <jdbc-info> 下的 <driver-class-name> 中的內容,先取得這個節點Element driverClassNameElement = (Element)XPath.selectSingleNode(rootEle, "http://sys-config/jdbc-info/driver-class-name"),注意,根節點前要使用兩個 "/" ,然后,用 driverClassNameElement.getText() 便可以取得這個節點下的信息。
如果一個節點下有多個名稱相同的子節點,可以用XPath.selectNodes()方法取得多個子節點的List,遍歷這個List就可以操作各個子節點的內容了。
下面是我寫的讀取上面xml文件的例子,比起文字描述更直觀一些吧:
- package com.why.jdom;
-
- import java.io.IOException;
- import java.util.Iterator;
- import java.util.List;
-
- import org.jdom.input.SAXBuilder;
- import org.jdom.xpath.XPath;
- import org.jdom.Document;
- import org.jdom.Element;
- import org.jdom.JDOMException;
-
- public class ReadXML {
-
-
-
-
- public static void main(String[] args) {
- SAXBuilder sax = new SAXBuilder();
- try {
- Document doc = sax.build("src/config.xml");
- Element rootEle = doc.getRootElement();
- Element driverClassNameElement = (Element)XPath.selectSingleNode(rootEle, "http://sys-config/jdbc-info/driver-class-name");
- String driverClassName = driverClassNameElement.getText();
- System.out.println("driverClassName = " + driverClassName);
-
- List provinceList = XPath.selectNodes(rootEle, "http://sys-config/provinces-info/province");
- for(Iterator it = provinceList.iterator();it.hasNext();){
- Element provinceEle = (Element)it.next();
- String proId = provinceEle.getAttributeValue("id");
- String proName = provinceEle.getAttributeValue("name");
-
- System.out.println("provinceId = " + proId + " provinceName = " + proName);
-
- List cityEleList = (List)provinceEle.getChildren("city");
-
- for(Iterator cityIt = cityEleList.iterator();cityIt.hasNext();){
- Element cityEle = (Element)cityIt.next();
- String cityId = cityEle.getAttributeValue("id");
- String cityName = cityEle.getText();
-
- System.out.println(" cityId = " + cityId + " cityName = " + cityName);
- }
- }
- } catch (JDOMException e) {
-
- e.printStackTrace();
- } catch (IOException e) {
-
- e.printStackTrace();
- }
-
- }
-
- }
package com.why.jdom;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.jdom.input.SAXBuilder;
import org.jdom.xpath.XPath;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
public class ReadXML {
/**
* @param args
*/
public static void main(String[] args) {
SAXBuilder sax = new SAXBuilder();
try {
Document doc = sax.build("src/config.xml");
Element rootEle = doc.getRootElement();
Element driverClassNameElement = (Element)XPath.selectSingleNode(rootEle, "http://sys-config/jdbc-info/driver-class-name");
String driverClassName = driverClassNameElement.getText();
System.out.println("driverClassName = " + driverClassName);
List provinceList = XPath.selectNodes(rootEle, "http://sys-config/provinces-info/province");
for(Iterator it = provinceList.iterator();it.hasNext();){
Element provinceEle = (Element)it.next();
String proId = provinceEle.getAttributeValue("id");
String proName = provinceEle.getAttributeValue("name");
System.out.println("provinceId = " + proId + " provinceName = " + proName);
List cityEleList = (List)provinceEle.getChildren("city");
for(Iterator cityIt = cityEleList.iterator();cityIt.hasNext();){
Element cityEle = (Element)cityIt.next();
String cityId = cityEle.getAttributeValue("id");
String cityName = cityEle.getText();
System.out.println(" cityId = " + cityId + " cityName = " + cityName);
}
}
} catch (JDOMException e) {
// TODO 自動生成 catch 塊
e.printStackTrace();
} catch (IOException e) {
// TODO 自動生成 catch 塊
e.printStackTrace();
}
}
}
二、寫xml文件
寫xml文件與讀取xml文件的操作類似,利用 org.jdom.output.XMLOutputter 就可以將處理好的xml輸出到文件了。可以設置文件的編碼方式,不過一般使用UTF-8就可以了。代碼如下:
- package com.why.jdom;
-
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
-
- import org.jdom.Document;
- import org.jdom.Element;
- import org.jdom.output.XMLOutputter;
-
- public class WriteXML {
-
-
-
-
-
- public static void main(String[] args) {
-
- Element rootEle = new Element("sys-config");
- Element provincesEle = new Element("provinces-info");
-
- Element provinceEle = new Element("province");
- provinceEle.setAttribute("id","hlj");
- provinceEle.setAttribute("name","黑龍江省");
-
- Element cityEle1 = new Element("city");
- cityEle1.setAttribute("id","harb");
- cityEle1.addContent("哈爾濱");
-
- Element cityEle2 = new Element("city");
- cityEle2.setAttribute("id","nj");
- cityEle2.addContent("嫩江");
-
-
- provinceEle.addContent(cityEle1);
- provinceEle.addContent(cityEle2);
- provincesEle.addContent(provinceEle);
- rootEle.addContent(provincesEle);
-
- Document doc = new Document(rootEle);
-
- XMLOutputter out = new XMLOutputter();
-
-
-
- String xmlStr = out.outputString(doc);
- System.out.println(xmlStr);
-
- try {
- out.output(doc, new FileOutputStream("c:/test.xml"));
- } catch (FileNotFoundException e) {
-
- e.printStackTrace();
- } catch (IOException e) {
-
- e.printStackTrace();
- }
-
- }
-
- }
http://www.cnblogs.com/ling_yun/archive/2011/01/19/1939674.html
下面是xml文件:
<?xml version="1.0" encoding="UTF-8"?>
<persons>
<person perid="1001">
<name>lhu</name>
<age>89</age>
<address>安徽淮北</address>
<sex>男</sex>
</person>
<person perid="1002">
<name>we</name>
<age>56</age>
<address>北京海淀</address>
<sex>女</sex>
</person>
</persons>
下面是解析上面的xml文件:
通過JDOM來解析,需要借助第三方的組件.jdom.jar,網上有1.0的版本下載
package cn.com.jdom;
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.jdom.Attribute;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.ProcessingInstruction;
import org.jdom.input.SAXBuilder;
import com.sun.xml.internal.bind.v2.runtime.Name;
/**
* jdom解析xml文件
*
* @author ly *
*/
public class JDomXML {
public JDomXML() {
}
/**
* 解析xml文件
* @param xmlFile
*/
public void parseXml(File xmlFile) {
SAXBuilder sax = new SAXBuilder();//在內存中建立一個sax文檔模型
try {
Document xmlDom = sax.build(xmlFile);//創建文檔
//獲得文件的根元素
Element root = xmlDom.getRootElement();
System.out.println("根元素是:"+root.getName());
//獲得根元素的子節點
List childList = root.getChildren();
Iterator listIt = childList.iterator();
while(listIt.hasNext()){
Element element = (Element)listIt.next();
System.out.println("孩子結點是:"+element.getName());
}
//獲得第一個孩子結點
Element firstChild = (Element) childList.get(0);
//獲得孩子結點的屬性
List attrList = firstChild.getAttributes();
Iterator attrIt = attrList.iterator();
while(attrIt.hasNext()){
Attribute attr = (Attribute ) attrIt.next();
System.out.println("第一個元素的屬性是:"+attr.getName());
//獲得屬性的值
System.out.println("屬性的值是:"+attr.getValue());
//獲得屬性的類型
System.out.println("屬性的類型是:"+attr.getAttributeType());
}
List sonList = firstChild.getChildren();
Iterator sonIt = sonList.iterator();
while(sonIt.hasNext()){
Element temp = (Element)sonIt.next();
System.out.println("屬性"+temp.getName()+"的值是:"+temp.getValue());
}
} catch (JDOMException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
JDomXML test = new JDomXML();
test.parseXml(new File("persons.xml"));
}
}