文件处理工具（上传和下载）

悠悠 2022-08-12 00:10 208阅读 0赞

import java.io.BufferedInputStream;
    import java.io.BufferedOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    /**
     * 文件上传工具
     * @Description
     * @Author iechenyb
     * @Date 2013-11-12 下午6:05:02   
     * @ModHistory 
     *
     */
    public class FileUtils {
    	private static final int BUFFER_SIZE = 1024*1024*20;//每次写入20m(可修改)
    	public InputStream in = null;
    	public OutputStream out = null;
    	private static final long serialVersionUID = 1L;
    	
    	/**new File(upload), dir 上传路径, map.get("id")）文件名
    	 * 保存文件到服务器
    	 * @Description
    	 * @Author iechenyb
    	 * @Date 2013-11-4 上午10:49:21 
    	 * @param upload 写入文件
    	 * @param path   存储路径
    	 * @param filename  上传文件名
    	 * @throws IOException
    	 * @ModHistory 
    	 */
        public static void saveFileFromInputStream(File upload,String path,String filename) throws IOException
        {      
    		 try {
    			in = new BufferedInputStream(new FileInputStream(upload));
    			out = new BufferedOutputStream(new FileOutputStream(path + "/"+ filename));//文件名无后缀
    			byte[] buffer = new byte[BUFFER_SIZE];
    			int byteread = 0;
    			while ((byteread = in.read(buffer)) != -1) {
    				out.write(buffer, 0, byteread);
    				out.flush();
    			}
    		 } catch (Exception e) {
    				e.printStackTrace();
    		 }finally{
    			in.close();
    			out.close();
    		 }
        }
      //文件不存在时下载缺省文件
    	public static void downDefault(HttpServletResponse res) throws Exception{
    		String path=PathUtil.getPathInfo("UPLOAD_FILE_PATH")+"/default.txt";
    		File file = new File(path);
    		if(!file.exists()){//缺省的文件不存在创建并写入内容
    			file.createNewFile();
    			FileWriter w = new FileWriter(file);
    			w.write("您要下载的文件不存在！请与管理员联系？");
    			w.close();
    		}
    		String name=new String(("文件不存在.txt").getBytes("GBK"),"ISO-8859-1");
    		downFile(name , path, res);
    	}
    	
    	/**
    	 * Map : name显示文件名  String
    	 * 		path 绝对全路径 String
    	 * 		res response
    	 * 		in 备选，文件输入流 FileInputStream
    	 * @Author tangyunan
    	 * @Date 2014-1-23 下午6:08:30 
    	 * @Description 
    	 * @param m
    	 * @throws Exception
    	 * @ModHistory 
    	 *
    	 */
    	public static void downFile(Map m,HttpServletResponse res) throws Exception{
    		String name =m.get("name")+"";
    		FileInputStream in=null;
    		String path="";
    		if(m.containsKey("in")){
    			in=(FileInputStream)m.get("in");
    		}
    		if(m.containsKey("path")){
    			path=m.get("path")+"";
    		}
    		if("".equals(path)&&in==null){
    			downDefault(res);
    		}else if(!"".equals(path)){
    			downFile(name,path,res);
    		}else {
    			dowStream(name,in,res);
    		}
    	}
    	//将制定路径的文件写出
    	public static void downFile(String name,String path,HttpServletResponse res) throws Exception{
    		FileInputStream in=null;
    		try{
    			in = new FileInputStream(new File(path));
    		}catch (Exception e){
    			downDefault(res);//下载缺省的文件
    			return ;
    		}
    		dowStream(name , in, res);
    	}
    	//将文件流in写出
    	public static void dowStream(String name,FileInputStream in,HttpServletResponse res) throws Exception{
    		OutputStream os = res.getOutputStream();
    		res.setHeader("Content-disposition", "attachment;filename="+name);
    		int b;
    		while ((b = in.read()) != -1) {
    			os.write(b);
    		}
    		in.close();
    		os.close();
    	}	
    
    }