xmloutput.java

来自「用Java开发的、实现类似Visio功能的应用程序源码」· Java 代码 · 共 165 行

/**
 *    $Id:XMLOutput.java $
 *
 *    Copyright 2004 ~ 2005  JingFei International Cooperation LTD. All rights reserved. *
 */
package com.jfimagine.jfdom;

import java.util.Iterator;
import java.util.List;

import java.io.PrintWriter;
import java.io.FileWriter;

import com.jfimagine.utils.log.*;
 
 /**
 * XMLOutput class.  A class used to output xml document.
 *
 * @author     CookieMaker    
 *
 * @version $Revision: 1.01 $
 */  
 public class XMLOutput{
	
	/**an internal log utility*/
	private static JFLogger m_logger	=JFLogManager.getLogger("com.jfimagine.jfdom.XMLOutPut");
	
        /**
         *   Write text content to a text file,replace existent content in the file.
         *   
         *   @param fileName name of the text file.
         *   @param content content of the text file.
         */
	public static void writeTextFile(String fileName,String content){
		try{		 
                	PrintWriter out = new PrintWriter( new FileWriter(fileName) );
                	out.print(content);
                	out.close();
                	out	=null;
                }catch(Exception e){
                	m_logger.error("WriteTextFile: "+e);
        	}
	}              


        /**
         *   save document to xml file.
         *   @param fileName an xml file name
         *   @param doc an XML Document contains the xml content.
         */
	public void saveDocument(String fileName,Document doc){
		if (fileName==null || fileName.length()==0 || doc==null)
			return;
		String xml	=getDocumentText(doc);
		writeTextFile(fileName,xml);
	} 

        /**
         *   get document as xml text.
         *   @param doc an XML Document contains the xml content.
         *   @return xml text.
         */
	public String getDocumentText(Document doc){
		StringBuffer buf	=new StringBuffer();
		writeXMLHead(buf);
		int level		=0;		
		Element root	=doc.getRoot();
		writeElement(buf,root,level);
		
		return buf.toString();		
	}
		
	
	/**
	 * write xml head
	 * @param buf A string buffer to write xml head
	 */
	private void writeXMLHead(StringBuffer buf){
		buf.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
		buf.append(XMLConst.XML_NEWLINE);
	}

	/**
	 * write a specified number of spaces
	 * @param buf A string buffer to write spaces
	 * @param num number of spaces
	 */
	private void writeSpace(StringBuffer buf, int num){
		while (num>0){
			buf.append(' ');
			num--;
		}
	}
        
        /**
         *  for special long text, e.g. image data, we
         *  need to seperate them by NEWLINE character.
         */
        private String adjustText(String text){
        	if (text==null || text.equals(""))
        		return "";
        	
        	//if has newLine/space character or total length less than a specified value,
        	//just return it with no change.
        	if (text.indexOf(XMLConst.XML_NEWLINE)>=0 || text.indexOf(' ')>=0 || text.length()<500)
        		return text;
        	
        	StringBuffer buf	=new StringBuffer();
        	for (int i=0; i<text.length(); i++){
        		buf.append(text.charAt(i));
        		if (i>0 && i%79==0)
        			buf.append(XMLConst.XML_NEWLINE);
        	}	
        	return buf.toString();
	}
	
	/**
	 * write element		                
	 * @param buf A string buffer to write element content
	 * @param element An element to write to buffer
	 * @param level Level of this element.
	 */
	private void writeElement(StringBuffer buf, Element element,int level){
		//leading spaces 
		int num	=level * 2;    
		writeSpace(buf,num);

		//head tag of an element		
		buf.append(XMLConst.XML_STARTTAG);
		buf.append(element.getTag());
		buf.append(XMLConst.XML_ENDTAG);
		
		if (element.hasChildren()){
			buf.append(XMLConst.XML_NEWLINE);
			writeElements(buf,element.getChildren(),level+1);
			//tail tag of an element
			writeSpace(buf,num);
		}else{
			buf.append(adjustText(element.getValue()));
		}

		buf.append(XMLConst.XML_ENDSTARTTAG);
		buf.append(element.getTag());
		buf.append(XMLConst.XML_ENDTAG);
		
		buf.append(XMLConst.XML_NEWLINE);
	}
        

	/**
	 * write sub elements
	 * @param buf A string buffer to write element content
	 * @param elementList Sub element list.
	 * @param level Level of this element list.
	 */
	private void writeElements(StringBuffer buf, List elementList,int level){
		Iterator it	=elementList.iterator();
		while(it!=null && it.hasNext()){
			Element element	=(Element)it.next();
			writeElement(buf,element,level);
		}
	}
        
        
}