commons-fileupload的文件上传

记得以前写过用commons-fileupload实现的文件上传，可现在又差不多忘了，
于是乎今天在网上找了写资料拼拼凑凑又重新写过了一遍，在此做个备忘!

public class FileUpload extends HttpServlet {


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}


	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();
		
		final long MAX_SIZE= 10 * 1024 * 1024;
		
		String fileFolder = this.getServletContext().getRealPath("/userFiles");
		
		//判断该请求是否是文件上传的请求
		boolean isMultipart = ServletFileUpload.isMultipartContent(request);
		
		if(isMultipart){
			DiskFileItemFactory factory = new DiskFileItemFactory();
			//设置上传文件时用于临时存放文件的内存大小
			factory.setSizeThreshold(10 * 1024);
			//设置存放临时文件的目录
			factory.setRepository(new File(fileFolder+"/temp"));
			
			ServletFileUpload upload = new ServletFileUpload(factory);
			//设置最大上传尺寸
			upload.setFileSizeMax(MAX_SIZE);
			
			try {
				List<FileItem> filelist = upload.parseRequest(request);
				for(Iterator<FileItem> it = filelist.iterator(); it.hasNext() ; ){
					FileItem item = it.next();
					//判断是form表单域还是上传文件file域
					if(item.isFormField()){
						//处理form表单域
						String name = item.getFieldName();
						String value = item.getString();
					}else{
						//处理fileUpload
						//得到表单域的名称
						String fieldName = item.getFieldName();
						//取得文件类型
						String contentType = item.getContentType();
						//文件的全路径
						String fileName = item.getName();
						//得到去除路径的文件名
						int index = fileName.lastIndexOf("\\");
						fileName = fileName.substring(index+1);
						
						//构建一个文件
						File uploadFile = new File(fileFolder ,fileName);
						//保存文件
						item.write(uploadFile);
						out.println("文件上传成功");
					}
				}
			} catch (FileUploadException e) {
				if(e instanceof FileSizeLimitExceededException ){
					out.println("文件太大,允许上传的最大大小为10MB");
				}
			} catch (Exception e) {
				out.println(e);
			}
		}
	}

}