在Servlet中要实现文件上传，需要以下第三方架包

jsp页面的表单应该设为post方式提交，并且设置 enctype="multipart/form-data" ，默认的为 enctype="application/x-www-form-urlencoded"

${message}为显示上传操作结果通知。

    
     			文件上传支持以下格式："txt","doc","docx","xls","xlsx","ppt","pdf","xml","html"
     
			文件上传：
     			
     
     
		
    
		${message}

后台实现如下，可以判断上传类型，注意：文件上传名重复，会覆盖原有文件，所以自己要加判断

protected void doPost(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {		request.setCharacterEncoding("utf-8");		String[] allowTypes = new String[]{"txt","doc","docx","xls","xlsx","ppt","pdf","xml","html"};		DiskFileItemFactory factory = new DiskFileItemFactory();		ServletFileUpload upload = new ServletFileUpload(factory);		String path = request.getSession().getServletContext().getRealPath("/files");		System.out.println(path);		try {			List
    
      items = (List
     
      ) upload.parseRequest(request);			Iterator itr = items.iterator();	        while (itr.hasNext()) {	        	 FileItem item = (FileItem) itr.next();	        	 if(item.isFormField()){	        		 System.out.println("文本信息");	        	 }else{	        		  if (item.getName() != null && !item.getName().equals("")) {	        			  String name = item.getName();  	        			  String type = name.substring(name.lastIndexOf('.')+1);	        			  boolean flag = false;	        			  for(String at:allowTypes){				        				  if(at.equals(type)){	        					  flag = true;	        				  }	        			  }	        			  if(flag==false){	        				  System.out.println("文件格式不支持");	        				  request.setAttribute("message", "文件格式不支持");	        			  }else{	        				  int start = name.lastIndexOf("\\");	        				  String filename = name.substring(start+1);  	        				  File file = new File(path+"/"+filename);		        			  item.write(file);		        			  request.setAttribute("message", "文件上传成功");	        			  }	        		  }else{	        			  System.out.println("请选择待上传文件");	        			  request.setAttribute("message", "请选择待上传文件");	        		  }	        	 }	        }		}catch (Exception e) {			e.printStackTrace();			request.setAttribute("message", "文件上传失败");		}		request.getRequestDispatcher("upload.jsp").forward(request, response);  	}
     
    

web.xml文件配置