fileutil.java

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package cn.myvideosite.util;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.Calendar;

import cn.myvideosite.exception.DownloadException;

import cn.myvideosite.util.MyRandom;;


public class FileUtil {
    private static final String ROOT="d:\\image2\\";
	private static final int timeout=88888;
	
	/**
	 * 根据系统当前时间，构造目录结构
	 * java.util.Date, Canlender 
	 * java.io.File  http://i3.sinaimg.cn/jc/bbs/p(/2008/0912/)+U1335P27T90D28792F1561DT+20080912140030.jpg
	 */
	private static String mkdirs(){
		Calendar cal=Calendar.getInstance();
		StringBuffer sb=new StringBuffer();		
		sb.append(cal.get(Calendar.YEAR)).append(File.separator).append(cal.get(Calendar.MONTH)+1)
		.append(cal.get(Calendar.DAY_OF_MONTH)).append(File.separator).append(cal.get(Calendar.HOUR_OF_DAY))
		.append(cal.get(Calendar.MINUTE)).append(File.separator).toString();		
		File f=new File(ROOT+sb.toString());
		if(!f.exists())			
			f.mkdirs();									
		return sb.toString();
	}
	
    /**
     * 
     * @return 依据当前系统时间加上随即数
     *  得到新文件名
     */
	private static String getNewFileName(String fileUrl){
		Calendar cal=Calendar.getInstance();
		SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMddHHmmss"); 
		String strDate=sdf.format(cal.getTime());
		String fileFormat=fileUrl.substring(fileUrl.lastIndexOf("."));		
		//System.out.println(mkdirs()+MyRandom.random()+strDate+fileFormat);
		return MyRandom.random()+strDate+fileFormat;		
	}
	
	public static String download(String fileUrl)throws DownloadException{		
		String path = mkdirs()+getNewFileName(fileUrl);	
		String fileName=ROOT+path;
		download(fileUrl,fileName);			
		return path.replace("\\", "/");
	}	
	
	/**
	 * @param args 文件下载工具类
	 */
	
	public static void download(String fileUrl,String savePath)throws DownloadException{		
		 BufferedOutputStream bos=null;
		 InputStream is=null;
		 HttpURLConnection urlconnection=null;
		 try {
			URL url=new URL(fileUrl);
		    urlconnection=(HttpURLConnection)url.openConnection();
			if(null!=urlconnection){
				urlconnection.setConnectTimeout(timeout);
				urlconnection.setReadTimeout(timeout);
				urlconnection.connect();									
			int i=urlconnection.getResponseCode();//  从 HTTP 响应消息获取状态码。
			if(i!=200) throw new  DownloadException("连接到："+fileUrl+"失败，返回CODE:"+i);
			
			int contentLength=urlconnection.getContentLength();//取得连接内容的长度
			
			is=urlconnection.getInputStream();//得到服务器返回的InputStream
			File outFile=new File(savePath);//写文件
			int readTotalLength=0;			
			byte[] barr= new byte[1024];
			
			bos=new BufferedOutputStream(new FileOutputStream(outFile));
			int readLength=0;
			
			while((readLength=is.read(barr))!=-1){
				bos.write(barr,0,readLength);
				readTotalLength+=readLength;
			}		
			if(readTotalLength<contentLength){      //校检是否下载正常
				bos.flush();
				is.close();
				bos.close();
				outFile.delete();
				throw new DownloadException("下载失败!!"+fileUrl); 
			   }
			bos.flush();
			}			
		} catch (IOException e) {
			
			new DownloadException(e);
		}finally{			
				try {
					if(is!=null){
					is.close();
					is=null;
					}
					if(bos!=null){
						bos.close();
						bos=null;
					}
				} catch (IOException e) {					
					e.printStackTrace();
				}				
		}
	}
	public static void main(String[] args){
		
		           // d:/image/2008/927/30/r4IJMA30TcX6pkv20080927030002.jpg
		            //d:/image/2008/927/259/phvG5HkOcr0A22j20080927025944.jpg
		//d:/image/2008/927/31/6uGM5qhaggPwSea20080927030116.jpg
		try {
			download("D:\\image\\2008\\927\\9386uGM5qhaggPwSea20080927030116.jpg");
		} catch (DownloadException e) {
			
			e.printStackTrace();
		}
		
		
	}
}