操作xml文件有关问题

操作xml文件问题
能不能像操作数据库那样读写xml文件？

[解决办法]
看看api里javax.xml这部分
要用到DocumentBuilderFactory，DocumentBuilder这些
[解决办法]
JDK 1.5 中还增加了 XPath，用于查询数据很方便的。
[解决办法]
jdomAPI
[解决办法]
可以用apche的类库，我前两天正好在公司写了个操作xml文件的类，给你看下:
..............

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
import org.jdom.output.Format;
import org.jdom.output.XMLOutputter;
import org.xml.sax.InputSource;

...........

DomainModel domainModel = (DomainModel) request.getSession().getAttribute("TABLE");
InputSource is = new InputSource("d:\\huaxia\\huaxiaweb\\src\\main\\resources\\myapp.struts.xml");
is.setEncoding("UTF-8");
SAXBuilder sb = new SAXBuilder();
Document structsXML;
try {
structsXML = sb.build(is);
} catch (JDOMException e1) {
// TODO Auto-generated catch block
logger.info(e1.getMessage());
return;
} catch (IOException e1) {
// TODO Auto-generated catch block
logger.info(e1.getMessage());
return;
}

// StructsXML文件的根元素
Element root = structsXML.getRootElement();

Element actionMapping = root.getChild("action-mappings");

boolean haveMainAction = false;
boolean haveUpdateAction = false;
boolean haveCreateAction = false;
java.util.List<Element> elements = actionMapping.getChildren();
for(Element el: elements){
if( el.getAttributeValue("path").equals( ("/" + domainModel.getTableNameInJava() + "MainAction"))
&& el.getAttributeValue("parameter").equals("method")
&& el.getAttributeValue("name").equals((domainModel.getTableNameInJavaFirstLow() + "Form"))){
logger.info(domainModel.getTableNameInJava() +"MainAction has already existed.");
haveMainAction = true;
}
if( el.getAttributeValue("path").equals( ("/" + domainModel.getTableNameInJava() + "CreateAction"))
&& el.getAttributeValue("input").equals( ("/" + domainModel.getTableNameInJava() + "Create.jsp"))){
logger.info(domainModel.getTableNameInJava() + "CreateAction has already existed.");
haveCreateAction = true;
}
if( el.getAttributeValue("path").equals( ("/" + domainModel.getTableNameInJava() + "UpdateAction"))
&& el.getAttributeValue("input").equals( ("/" + domainModel.getTableNameInJava() + "Update.jsp"))){
logger.info(domainModel.getTableNameInJava() + "UpdateAction has already existed.");
haveUpdateAction = true;
}
}


[解决办法]
我解释下：
 InputSource is = new InputSource("d:\\huaxia\\huaxiaweb\\src\\main\\resources\\myapp.struts.xml"); 
把一个xml文件读入InputSource类 这个类是jdom的一个部分。
is.setEncoding("UTF-8"); 
SAXBuilder sb = new SAXBuilder(); 
Document structsXML; 

try { 
structsXML = sb.build(is); 
} catch (JDOMException e1) { 
// TODO Auto-generated catch block 
logger.info(e1.getMessage()); 
return; 
} catch (IOException e1) { 
// TODO Auto-generated catch block 
logger.info(e1.getMessage()); 
return; 
} 
把这个文件和一个Document类关联起来

得到这个Document的根元素
Element root = structsXML.getRootElement(); 
根元素的所有二级元素， 放在list中
java.util.List <Element> elements = actionMapping.getChildren(); 

然后通过element.setAttributes等等方法来修改，
最后记得把这个document重新写入io流放入xml文件即可，
上google搜索jdom 有文档下载 英文




[解决办法]
你可以读xml文件,从xml的属性来取得xml中的数据
f = new File(SavingFilePath,SavingFileName);//你的xml的路径名和文件名
DocumentBuilderFactory factory=DocumentBuilderfactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(f);
String str = doc.getElementsByTagName(属性).item(num).getFirstChild().getNodeValue();
//num=那个属性排在在第几就是几.
这样就可以读到xml的文件了...你就可以操作XML文件..
[解决办法]
package run;
import org.jdom.*;
import org.jdom.output.*;
import java.io.*;
public class WriteXML{
public void BuildXML() throws Exception {
Element root,student,number,name,age,firstname,lastname;
root = new Element("student-info"); //生成根元素：student-info
student = new Element("student"); //生成元素：student(number,name,age)
number = new Element("number");
name = new Element("name");
age = new Element("age");
firstname = new Element("firstname");
lastname = new Element("lastname");
Document doc = new Document(root); //将根元素植入文档doc中
root.setText("root_name");
number.setText("001");
firstname.setText("yu");
lastname.setText("haiming");
age.setText("24");
student.addContent(number);
student.addContent(name);
student.addContent(age);
name.addContent(firstname);
name.addContent(lastname);
root.addContent(student);

root.setAttribute("width", "100%");
root.setAttribute("height", "860px");
root.setAttribute("bgcolor", "red");
root.setAttribute("name", "student");
Format format = Format.getCompactFormat();
format.setEncoding("gb2312"); //设置xml文件的字符为gb2312
format.setIndent(" "); //设置xml文件的缩进为4个空格
XMLOutputter XMLOut = new XMLOutputter(format);//元素后换行一层元素缩四格 
XMLOut.output(doc, new FileOutputStream("studentinfo.xml"));
}
public static void main(String[] args) throws Exception {
WriteXML w = new WriteXML();
System.out.println("Now we build an XML document .....");
w.BuildXML();
System.out.println("finished!");
}
}