Jsp+Servlet实现文件上传下载 文件上传（一）

 <%@ page contentType="text/html;charset=UTF-8" language="java" %><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>   
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 package servlet; 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; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.Calendar; import java.util.Iterator; import java.util.List; import java.util.UUID; /** * 处理文件上传 * * @author xusucheng * @create 2017-12-27 **/ @WebServlet("/UploadServlet") public class UploadServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //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(); } //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集合，每一个FileItem对应一个Form表单的输入项 List items = upload.parseRequest(request); Iterator 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！"); } //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 FileOutputStream out = 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 out.write(buffer, 0, len); } //关闭输入流 in.close(); //关闭输出流 out.close(); //删除临时文件 TODO item.delete(); //将上传文件信息保存到附件表中 TODO } } } catch (FileUploadBase.FileSizeLimitExceededException e) { e.printStackTrace(); request.setAttribute("errorMessage", "单个文件超出最大值！！！"); request.getRequestDispatcher("pages/upload/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("pages/upload/upload.jsp").forward(request, response); return; } catch (FileUploadException e) { e.printStackTrace(); request.setAttribute("errorMessage", "文件上传失败！！！"); request.getRequestDispatcher("pages/upload/upload.jsp").forward(request, response); return; } request.setAttribute("errorMessage", errorMessage); request.getRequestDispatcher("pages/upload/upload.jsp").forward(request, response); } @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"}; for (int i = 0; i