#文件上传#

upload.java

//commons.apache.org 下的一个组件 upload
//jar:commons-fileupload-1.2.2.jar,依赖jar:commons-io-1.4.jar

<form action="fileUpload" method="post" enctype="multipart/form-data">
      文件描述：<input type="text" name="filedesc"><br/>
    	<input type="file" name="myfile"><br/>
    	<input type="submit" value="提交"/>
</form>
    
if(ServletFileUpload.isMultipartContent(request)){//获取请求的方式改变
  		//创建一个临时文件夹
			DiskFileItemFactory factory = new DiskFileItemFactory();
			factory.setRepository(new File("I:/test/temp"));
			//创建一个新文件上传处理程序
			ServletFileUpload upload = new ServletFileUpload(factory);
			
			try {
				//解析请求,非表单上传元素和表单上传的元素都遍历出来
				List<FileItem> items = upload.parseRequest(request);
				
				String filedesc = null;
				for(FileItem fileItem : items){
					if(fileItem.isFormField()){
						//普通表单元素（非file）
						if(fileItem.getFieldName().equals("filedesc")){
							filedesc = fileItem.getString();
						}
						System.out.println(fileItem.getFieldName());//filedesc
						System.out.println(fileItem.getName());//null
						System.out.println(fileItem.getString());//filedesc的值value
					}else{ 
						//type为file的表单元素
						System.out.println("---------------------------");
						System.out.println("Name:"+fileItem.getName());//上传文件的名字
						System.out.println("ContentType:"+fileItem.getContentType());//上传文件的格式
						System.out.println("Size:"+fileItem.getSize());//上传文件的大小
						
						String fileName = fileItem.getName();
						String exeName = fileName.substring(fileName.lastIndexOf("."));
						
						long MaxSize = 1024*1024*3;
						if(".jpg".equals(exeName) || ".png".equals(exeName) || ".gif".equals(exeName)){
							
							if(fileItem.getSize()>MaxSize){
								response.sendRedirect("toFile?code=1002");
							}else{
								UUID uuid = UUID.randomUUID();
								System.out.println(uuid);
								fileName = uuid+exeName;
								// 显示上传的文件
								File path = new File(getServletContext().getRealPath("/")+"upload");//获得根路径
								System.out.println(path);
								if(!path.exists()){
									path.mkdir();
								}
								File file = new File(path,fileName);
								InputStream inputStream = fileItem.getInputStream();
								BufferedInputStream bis = new BufferedInputStream(inputStream);
								BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
								
								int len = -1;
								byte[] b = new byte[1024];
								while((len=bis.read(b)) != -1){
									bos.write(b, 0, len);
								}
								bos.flush();
								bos.close();
								bis.close();
								
								request.setAttribute("fileName", fileName);
								request.getRequestDispatcher("/WEB-INF/views/showpic.jsp").forward(request, response);
							}
						}else{
							response.sendRedirect("toFile?code=1001");
						}
					}
				}
			} catch (FileUploadException e) {
				e.printStackTrace();
			}
			
			
		}else{
			response.sendError(500, "页面访问有错");
		}