详细说明：
package action; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.util.Iterator; import java.util.List; 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.FileUploadException; import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException; import org.apache.commons.fileup load.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; public class FileUploadServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { final long MAX_SIZE = 300 * 1024 * 1024;// 设置上传文件最大值 // 允许上传的文件格式的列表 final String[] allowedExt = new String[] { "jpg", "jpeg", "gif", "txt", "doc", "mp3", "wma", "m4a", "rar", "zip" }; response.setContentType("text/html"); // 设置字符编码为UTF-8, 统一编码，处理出现乱码问题 response.setCharacterEncoding("UTF-8"); // 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload DiskFileItemFactory dfif = new DiskFileItemFactory(); dfif.setSizeThreshold(4096);// 设置上传文件时用于临时存放文件的内存大小,这里是4K.多于的部分将临时存在硬盘 dfif.setRepository(new File(request.getRealPath("/") + "ImagesUploadTemp"));// 设置存放临时文件的目录,web根目录下的ImagesUploadTemp目录 // 用以上工厂实例化上传组件 ServletFileUpload sfu = new ServletFileUpload(dfif); // 设置最大上传大小 sfu.setSizeMax(MAX_SIZE); PrintWriter out = response.getWriter(); // 从request得到所有上传域的列表 List fileList = null; try { fileList = sfu.parseRequest(request); } catch (FileUploadException e) {// 处理文件尺寸过大异常 if (e instanceof SizeLimitExceededException) { out.println("文件尺寸超过规定大小:" + MAX_SIZE + "字节"); out .println("
返回"); return; } e.printStackTrace(); } // 没有文件上传 if (fileList == null || fileList.size() == 0) { out.println("请选择上传文件
"); out.println("
返回"); return; } // 得到所有上传的文件 Iterator fileItr = fileList.iterator(); // 循环处理所有文件 while (fileItr.hasNext()) { FileItem fileItem = null; String path = null; long size = 0; // 得到当前文件 fileItem = (FileItem) fileItr.next(); // 忽略简单form字段而不是上传域的文件域(
等) if (fileItem == null || fileItem.isFormField()) { continue; } // 得到文件的完整路径 path = fileItem.getName(); // 得到文件的大小 size = fileItem.getSize(); if ("".equals(path) || size == 0) { out.println("请选择上传文件
"); out .println("
返回"); return; } // 得到去除路径的文件名 String t_name = path.substring(path.lastIndexOf("\\") + 1); System.out.println(t_name); // 得到文件的扩展名(无扩展名时将得到全名) String t_ext = t_name.substring(t_name.lastIndexOf(".") + 1); System.out.println(t_ext); // 拒绝接受规定文件格式之外的文件类型 int allowFlag = 0; int allowedExtCount = allowedExt.length; for (; allowFlag < allowedExtCount; allowFlag++) { if (allowedExt[allowFlag].equals(t_ext)) break; } if (allowFlag == allowedExtCount) { out.println("请上传以下类型的文件
"); for (allowFlag = 0; allowFlag < allowedExtCount; allowFlag++) out.println("*." + allowedExt[allowFlag] + " "); out .println("
返回"); return; } long now = System.currentTimeMillis(); // 根据系统时间生成上传后保存的文件名 String prefix = String.valueOf(now); // 保存的最终文件完整路径,保存在web根目录下的ImagesUploaded目录下 String u_name = request.getRealPath("/") + "ImagesUploaded/" + prefix + "." + t_ext; //String filename = prefix + "." + t_ext; //根据原文件名保存文件 String filename=t_name; try { // 保存文件到C:\\request.getRealPath("/")目录下 fileItem.write(new File(request.getRealPath("/") + filename)); System.out.println(filename); out.println("文件上传成功. 已保存为: " + t_name + " 文件大小: " + size + "字节
"); out .println("
继续上传"); } catch (Exception e) { e.printStackTrace(); } } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); } } ...展开收缩
