xmlprocess.java

这是有关于一个视频自动压缩系统的java+xml构建的代码

package autoencodeinfinit.XMLProcess;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.*;
import java.util.Properties;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.*;

/**
 * This class include the function of load in xml documents , write in xml documents
 * and append , modify ,remove any node of ths document.
 * @version 0.1
 * @author ulysess
 */
public class XMLProcess {
    private File docFile = null; 
    private Document doc = null , newdoc = null;
    private Element root = null;
    private String orgiadd = "";
    
    /**
     * Constructor, you need transport a parameter of the xml file address; 
     * please note this constructor will ignore the wihlespace in the xml file! 
     * @param fi the file address you want to load
     */
    public XMLProcess(String fi) {
       try {
           docFile = new File(fi);
           this.orgiadd = fi;
           DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
           DocumentBuilder db = dbf.newDocumentBuilder();
           doc = db.parse(docFile);
           doc.normalizeDocument();
           doc.normalize();
           } catch (javax.xml.parsers.ParserConfigurationException pce) {
                System.out.println("The parser was not configured correctly.");
                System.exit(1);
           } catch (java.io.IOException ie) {
                System.out.println("Cannot read input file.");
                System.exit(1); 
           } catch (org.xml.sax.SAXException se) {
                System.out.println("Problem occured parsing the file.");
                System.exit(1);
           } catch (java.lang.IllegalArgumentException ae) {
                System.out.println("Please specify an XML source.");
                System.exit(1);
           }
      
       root = doc.getDocumentElement();
       root.normalize();
    }
    
    /**
     * return the DocumentElement of this xml
     * @return the root document element
     */
    public Element getRoot() {
        
        System.out.println("The root element is "  + "\t" +root.getNodeName() );
        
        return root;
    }
    
    /**
     * return a NodeList of the children nodes of document element 
     * @return the children list of root node
     */
    public NodeList getChildNodes() {
        return this.root.getChildNodes();
    }
    
    /**
     * return a NodeList of the children nodes of specified node and the index of
     * this node , if only have one ,you need set the index as 0;
     * @param nodename the element name 
     * @param index the index of the element if there has only one ,it must be 0;
     * @return a NodeList of the children List
     */
    public NodeList getChildNodes(String nodename,int index) {
        NodeList children = null;
        if ((children = this.doc.getElementsByTagName(nodename) ).getLength()>0) {
            
            children = children.item(index).getChildNodes();
        }

        return children;
    }
 
    /**
     * set the value of a element
     * general you can get this by using getChildNodes("the name of element 
     * which you want to change value,0).item(0).setNodeValue("value you want to set")
     * @param ele  the element node you want to be set
     * @param value the value of this element
     */
    public void setValue(Element ele,String value) {
        ele.getFirstChild().setNodeValue(value);
    }
    
    /**
     * insert a new element node and its value node as a last children node of "eleti"
     * if you need insert only a element ,transmit a null string as nodevalue
     * @param eleti  the parent element node of the element you want to insert
     * @param nodename the name of the element you want to insert
     * @param nodevalue the value of the element you want to insert
     */
    public Element insertNodeIn(Element eleti,String nodename,String nodevalue) {
        Element newele = doc.createElement(nodename);
        if(nodevalue != null) {
                Text elevalue = doc.createTextNode(nodevalue);
                newele.appendChild(elevalue);
        }
        return (Element) eleti.insertBefore(newele , null );
    }
    
    /**
     * insert a new element node and its value node as a children node of "eleti"
     * before the children node "insertbefore"
     * @param eleti  the parent element node of the element you want to insert
     * @param insertbefore the sibling element you want to insert before
     * @param nodename the name of the element you want to insert
     * @param nodevalue the value of the element you want to insert
     */
    public Element insertNodeIn(Element eleti,Element insertbefore , String nodename,String nodevalue) {
        Element newele = doc.createElement(nodename);
        if(nodevalue != null) {
                Text elevalue = doc.createTextNode(nodevalue);
                newele.appendChild(elevalue);
        }
        
        return (Element) eleti.insertBefore(newele , insertbefore);
    }    
    
    /**
     * remove all element node named rm from the ele node
     * @param ele the parent node of the element to be removed
     * @param rm the name of the element to be removed
     */
    public void removeNode(Element ele,String rm) {
        
        ele.removeChild(ele.getElementsByTagName(rm).item(0).getFirstChild());
    }
    
    /**
     * write the xml document in memory into the disk with address newadd
     * @param newadd if newadd is null this method will flush the orginal xml document
     */
    public void WriteDocument(String newadd) {
        if (newadd == null) {
            this.WriteDocument(this.orgiadd);
        }
        else {
            DOMSource doms = new DOMSource(this.doc);
            File outf = new File(newadd);
            StreamResult sr = new StreamResult(outf);
            try {
                TransformerFactory tf=TransformerFactory.newInstance();
                Transformer t=tf.newTransformer ();       
                //call the method transform() of Transformer object (XSLT engine)
                Properties properties = t.getOutputProperties();   
                properties.setProperty(OutputKeys.ENCODING,"UTF-8"); 
                t.setOutputProperties(properties);
                t.transform(doms, sr);

            } catch (TransformerConfigurationException tce)
            {			
		System.out.println("Transformer Configuration Exception\n");
		tce.printStackTrace();		
            } catch (TransformerException te) 
            {			
		System.out.println ("Transformer Exception\n");			
		te.printStackTrace ();		
            }			

        }
    }
    
    /**
     * create a new XMLFile  in the specify location 
     * @param add 
     * @return a new XMLProcess object
     */
    public static XMLProcess CreateXMLFile(String add){
        File fi = null;
        FileWriter fw = null; 
        XMLProcess newxmlfile = null;
        try {
            fi = new File(add);
            if(fi.exists()) {
                System.out.println("File exist");
                return null;
            }
            else {
                if( !fi.createNewFile() ) {
                    System.out.println("create file failed");
                    return null;
                }
                
            }
            fw = new FileWriter(fi);
            fw.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?><root></root>");
            fw.flush();
            fw.close();
        } catch (IOException e) {
            System.out.println("Exception :" + e);
        }
       
        newxmlfile = new XMLProcess(add);
        
        
        return newxmlfile;
    }
}