文件上传

首先写一个文件上传的页面

jsp页面:

    
     
    
      
               
        
                     
文件描述
                     
                
                
                     
文件上传
                     
                
                
                     
                
           
      
     

在写servlet前解决文件重名问题

使用UUID作为随机的文件名

public class UUIDUtils {    public static String getUUID(){        return UUID.randomUUID().toString().replace("-", "");    }        public static String getUUIDFileName(String fileName){        return UUID.randomUUID().toString().replace("-", "")+"_"+fileName;    }}

解决一个目录下存放的文件过多的问题

public class UploadUtils {    public static String getPath(String uuidFileName){        // 使用唯一文件名.hashCode();        int code1 = uuidFileName.hashCode();        int d1 = code1 & 0xf; // 获得到1级目录.        int code2 = code1 >>> 4;        int d2 = code2 & 0xf; // 获得到2级目录.        return "/"+d1+"/"+d2;    }}

此处的servlet是用的servlet3.0

/** * 文件上传的Servlet */@WebServlet("/UploadServlet")@MultipartConfigpublic class UploadServlet extends HttpServlet {    private static final long serialVersionUID = 1L;    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // 接收普通数据:        request.setCharacterEncoding("UTF-8");        String filedesc = request.getParameter("filedesc");        System.out.println("文件描述"+filedesc);        // 接收文件:        Part part = request.getPart("upload");                long size = part.getSize();// 获得文件大小:        System.out.println("文件大小:"+size);        String name = part.getName();        System.out.println("文件表单中的name属性的名称"+name);        // 获得文件名:        String header = part.getHeader("Content-Disposition");        int idx = header.lastIndexOf("filename=\"");        String fileName = header.substring(idx+10, header.length()-1);        System.out.println("文件名:"+fileName);        // 获得文件内容:        InputStream is = part.getInputStream();        // 获得upload的路径:        String path = this.getServletContext().getRealPath("/upload");        // 获得文件的唯一文件名:        String uuidFileName = UUIDUtils.getUUIDFileName(fileName);        String realPath = path+UploadUtils.getPath(uuidFileName);        File file = new File(realPath);        if(!file.exists()){            file.mkdirs();        }        OutputStream os = new FileOutputStream(realPath+"/"+uuidFileName);        byte[] b = new byte[1024];        int len = 0;        while((len = is.read(b))!=-1){            os.write(b, 0, len);        }        is.close();        os.close();    }    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doGet(request, response);    }}