服务端Servlet实现文件上传的示例代码

示例代码使用了两个开源框架：commons-io.jar和commons-fileupload.jar

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		boolean isMultipart = ServletFileUpload.isMultipartContent(request);
		if(isMultipart) {
			String dirPath = request.getSession().getServletContext().getRealPath("/files");
			System.out.println(dirPath);
			
			File dir = new File(dirPath);
			if(!dir.exists()) {
				dir.mkdirs();
			}
			
			FileItemFactory factory = new DiskFileItemFactory();
			ServletFileUpload upLoad = new ServletFileUpload(factory);
			
			try {
				List<FileItem> items = upLoad.parseRequest(request);
				for(FileItem item: items) {
					if(item.isFormField()) {
						String name = item.getFieldName();// 得到请求参数的名称
						String value = item.getString();// 得到请求参数的内容
						System.out.println("name : "+name+"\tvalue : "+value);
					} else {
						// 获得文件名称。这里加上系统时间是为了可以多次上传同一张图片
						String fileName = System.currentTimeMillis()+item.getName();
						item.write(new File(dir, fileName));
					}
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		} else {
			doGet(request, response);
		}
	}