package com.zhangjun.edu.exportExcel;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.Date;

import org.w3c.dom.*;
/**
 * <p>Description:下载生成CSV格式的EXCEL</p>
 * @author 张军
 * @version 1.0
 * @date 2012-10-02
 */
@SuppressWarnings("serial")
public class Dom2CsvServlet extends HttpServlet
{
    static final String CONTENT_TYPE = "text/csv;charset=GB2312";

    public void init( ServletConfig config )
        throws ServletException
    {
        super.init( config );
    }


    public void destroy()
    {
    }


    public String getServletInfo()
    {
        return (super.getServletInfo());
    }


    // Handle the HTTP GET request
    public void doGet( HttpServletRequest request, HttpServletResponse response )
        throws ServletException, IOException
    {
    	try
    	{
	      
	        
	        String sessionName=(String)request.getSession().getAttribute("sname");
	        Document dom=(Document)request.getSession().getAttribute(sessionName);
	        if(dom==null || sessionName==null)
	        {
	        	response.setContentType( CONTENT_TYPE );
	        	PrintWriter out = response.getWriter();
	        	out.println("超时请重新登陆!");
	        	
		}
		else
		{
	        String csv=dom2Csv(dom);
	        byte []bbb = csv.getBytes("GBK");
			response.setContentType("application/octet-stream;charset=GB2312"); 
			String excelName = new Date().getTime()+"";
			String filename=excelName+".csv";
			response.setHeader("Content-Disposition","attachment; filename="+filename);
			OutputStream out2 = response.getOutputStream();
			out2.write(bbb);
			out2.close();
			response.setStatus(response.SC_OK);
		}

		}
		catch (Exception e)
		{
			System.out.println("----------ex in servlet:"+e);
			e.printStackTrace();
		}
        
    }


    // Handle the HTTP POST request
    public void doPost( HttpServletRequest request, HttpServletResponse response )
        throws ServletException, IOException
    {
    }
    
    private String dom2Csv(Document dom)
    {
    	StringBuffer bf=new StringBuffer();
    	
    	try
    	{
			dom.normalize();
			Node root=(Node)dom.getDocumentElement();
			NodeList nodeRowList=root.getChildNodes();
			
			if (nodeRowList.getLength()>0)	//dom is not null
			{
				Node nodeRowTitle=nodeRowList.item(0);
				NodeList nodeItemList=nodeRowTitle.getChildNodes();
				for (int j=0;j<nodeItemList.getLength();j++)
				{
					Node nodeItem=nodeItemList.item(j);
					if (j!=0)
					{
						bf.append(",");
					}
					bf.append("\"");
					bf.append(nodeItem.getChildNodes().item(0).getChildNodes().item(0).getNodeValue());	// /documents/row/item/name
					bf.append("\"");
				}
				bf.append("\n");
			}
			
			for (int i=0;i<nodeRowList.getLength();i++)
			{
				Node nodeRow=nodeRowList.item(i);
				NodeList nodeItemList=nodeRow.getChildNodes();
				for (int j=0;j<nodeItemList.getLength();j++)
				{
					Node nodeItem=nodeItemList.item(j);
					if (j!=0)
					{
						bf.append(",");
					}
					String itemtype=nodeItem.getChildNodes().item(2).getChildNodes().item(0).getNodeValue();	//itemtype
					itemtype=itemtype.trim();
					NodeList temp=nodeItem.getChildNodes().item(1).getChildNodes();
					if (temp==null || temp.getLength()==0)
					{
						bf.append("\"\"");
					}					
					else if (itemtype!=null && (itemtype.equals("CHAR")||itemtype.equals("String")||itemtype.equals("VARCHAR")||itemtype.equals("VARCHAR2")))
					{
						bf.append("\"");
						bf.append(nodeItem.getChildNodes().item(1).getChildNodes().item(0).getNodeValue());	
						bf.append("\t\"");
					}
					else
					{
						bf.append(nodeItem.getChildNodes().item(1).getChildNodes().item(0).getNodeValue());
					}
				}
				bf.append("\n");
			}
    	}
    	catch (Exception e)
    	{
    		e.printStackTrace();
    	}
    	return bf.toString();
    }
}