Jsp文件上传

commons-fileupload-1.4.jar

commons-io-2.7.jar

@Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("UTF-8");
        //1 先判断上传的数据是否多段数据
        if(ServletFileUpload.isMultipartContent(req)){
            //创建FileItemFactory工厂实现类
            FileItemFactory fileItemFactory = new DiskFileItemFactory();
            //创建用于解析上传数据的工具类ServletFileUpload
            ServletFileUpload servletFileUpload = new ServletFileUpload(fileItemFactory);
            //解析上传的数据,得到每一个表单项FileItem
            try {
                List<FileItem> fileItems = servletFileUpload.parseRequest(req);
                for (FileItem f:fileItems
                     ) {
                    if(f.isFormField()){
                        //普通表单项
                        System.out.println("表单项的name属性值"+f.getFieldName());
                        System.out.println("表单项的value属性值"+f.getString("UTF-8"));
                    }else{
                        //上传的文件
                        System.out.println("表单项的name属性值"+f.getFieldName());
                        System.out.println("上传的文件名"+f.getName());
                        f.write(new File("E:\\upload\\firstweb\\"+f.getName()));
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取要下载的文件名
        String downloadFileName = "1.jpg";
        //读取要下载的文件内容
        ServletContext servletContext = getServletContext();
        //获取要下载的文件类型
        String mimeType = servletContext.getMimeType("/file/" + downloadFileName);
        //通过响应头告诉客户端返回的数据类型
        resp.setContentType(mimeType);
        //告诉客户端收到的数据用于下载
        //Content-Disposition 表示收到的数据怎么处理
        //attachment 表示附件,需要下载使用
        //filename 表示要下载的文件
        resp.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(downloadFileName,"UTF-8"));
        InputStream resourceAsStream = servletContext.getResourceAsStream("/file/" + downloadFileName);
        //获取响应的输出流
        OutputStream outputStream = resp.getOutputStream();
        //将输入流复制给输出流 回传给客户端
        IOUtils.copy(resourceAsStream,outputStream);
    }