文件上传下载完整篇

package com.byzx.web.servlet; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Calendar; import java.util.Iterator; import java.util.List; import java.util.UUID; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadBase; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.ProgressListener; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; /** * 处理文件上传 * * @author wangkun * @create 2017-12-27 **/ public class UploadServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); // 设置文件上传基本路径 String savePath = this.getServletContext().getRealPath( "/WEB-INF/uploadFiles"); // 设置临时文件路径 String tempPath = this.getServletContext().getRealPath( "/WEB-INF/tempFiles"); File tempFile = new File(tempPath); if (!tempFile.exists()) { tempFile.mkdir(); } // 计算成功上传文件个数 int successCount = 0; // 定义异常消息 String errorMessage = ""; // 创建file items工厂 DiskFileItemFactory factory = new DiskFileItemFactory(); // 设置缓冲区大小 factory.setSizeThreshold(1024 * 100); // 设置临时文件路径 factory.setRepository(tempFile); // 创建文件上传处理器 ServletFileUpload upload = new ServletFileUpload(factory); // 监听文件上传进度 ProgressListener progressListener = new ProgressListener() { public void update(long pBytesRead, long pContentLength, int pItems) { System.out.println("正在读取文件： " + pItems); if (pContentLength == -1) { System.out.println("已读取： " + pBytesRead + " 剩余0"); } else { System.out.println("文件总大小：" + pContentLength + " 已读取：" + pBytesRead); } } }; upload.setProgressListener(progressListener); // 解决上传文件名的中文乱码 upload.setHeaderEncoding("UTF-8"); // 判断提交上来的数据是否是上传表单的数据 if (!ServletFileUpload.isMultipartContent(request)) { // 按照传统方式获取数据 return; } // 设置上传单个文件的大小的最大值，目前是设置为1024*1024字节，也就是1MB upload.setFileSizeMax(1024 * 1024); // 设置上传文件总量的最大值，最大值=同时上传的多个文件的大小的最大值的和，目前设置为10MB upload.setSizeMax(1024 * 1024 * 10); try { // 使用ServletFileUpload解析器解析上传数据，解析结果返回的是一个List<FileItem>集合，每一个FileItem对应一个Form表单的输入项 List<FileItem> items = upload.parseRequest(request); Iterator<FileItem> iterator = items.iterator(); while (iterator.hasNext()) { FileItem item = iterator.next(); // 判断jsp提交过来的是不是文件 if (item.isFormField()) { errorMessage = "请提交文件！"; break; } else { // 文件名 String fileName = item.getName(); if (fileName == null || fileName.trim() == "") { System.out.println("文件名为空！"); break; } // 处理不同浏览器提交的文件名带路径问题 fileName = fileName .substring(fileName.lastIndexOf("\\") + 1); // 文件扩展名 String fileExtension = fileName.substring(fileName .lastIndexOf(".") + 1); // 判断扩展名是否合法 /*if (!validExtension(fileExtension)) { errorMessage = "上传文件非法！"; item.delete(); break; }*/ // 获得文件输入流 InputStream in = item.getInputStream(); // 得到保存文件的名称 String saveFileName = createFileName(fileName); // 得到文件保存路径 String realFilePath = createRealFilePath(savePath, saveFileName); // 创建文件输出流 System.out.println("real:" + realFilePath); FileOutputStream fos = new FileOutputStream(realFilePath); // 创建缓冲区 byte buffer[] = new byte[1024]; int len = 0; while ((len = in.read(buffer)) > 0) { // 写文件 fos.write(buffer, 0, len); } // 关闭输入流 in.close(); // 关闭输出流 fos.close(); // 删除临时文件 TODO System.out.println("delete..."); item.delete(); // 将上传文件信息保存到附件表中 TODO successCount++; } } } catch (FileUploadBase.FileSizeLimitExceededException e) { e.printStackTrace(); request.setAttribute("errorMessage", "单个文件超出最大值！！！"); request.getRequestDispatcher("upload.jsp").forward( request, response); return; } catch (FileUploadBase.SizeLimitExceededException e) { e.printStackTrace(); request.setAttribute("errorMessage", "上传文件的总的大小超出限制的最大值！！！"); request.getRequestDispatcher("upload.jsp").forward( request, response); return; } catch (FileUploadException e) { e.printStackTrace(); request.setAttribute("errorMessage", "文件上传失败！！！"); request.getRequestDispatcher("upload.jsp").forward( request, response); return; } request.setAttribute("errorMessage", errorMessage); if(successCount>0){ // 成功上传文件 out.println("<script>alert('文件上传成功!');location.href='upload.jsp';</script>"); }else{ out.println("<script>location.href='upload.jsp';</script>"); } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } private boolean validExtension(String fileExtension) { String[] exts = { "jpg", "txt", "doc", "pdf","png" }; for (int i = 0; i < exts.length; i++) { if (fileExtension.equals(exts[i])) { return true; } } return false; } private String createFileName(String fileName) { return UUID.randomUUID().toString() + "_" + fileName; } /** * 根据基本路径和文件名称生成真实文件路径 * * @param basePath * @param fileName * @return */ private String createRealFilePath(String basePath, String fileName) { int hashCode = fileName.hashCode(); int dir1 = hashCode&0xf;// 取1~4位 int dir2 = (hashCode&0xf0)>>4;//取5~8位 String directory = ""+dir1+File.separator+dir2; File file = new File(basePath,directory); if(!file.exists()){ file.mkdirs(); } return file.getAbsolutePath() + File.separator+ fileName; } /*private String createRealFilePath(String basePath, String fileName) { Calendar today = Calendar.getInstance(); String year = String.valueOf(today.get(Calendar.YEAR)); String month = String.valueOf(today.get(Calendar.MONTH) + 1); String upPath = basePath + File.separator + year + File.separator + month + File.separator; File uploadFolder = new File(upPath); if (!uploadFolder.exists()) { uploadFolder.mkdirs(); } String realFilePath = upPath + fileName; return realFilePath; }*/ }