Servlet3.0, the improvement of some of the API, simplifying Java Web development.
For example, file upload. The traditional file upload needs the help of tools such as common-fileupload, very complex, with Servlet3.0 the API is very simple.
Upload page upload.jsp / upload.html
<form method="post" action="upload" enctype="multipart/form-data"> 选择文件：<input type="file" id="file" name="file"><br> <input type="submit" value="提交"> </form>
Processing the uploaded Servlet
// Servlet3.0 configuration corresponding to the web.xml @WebServlet (name = "the Upload", urlPatterns = { "/ Upload" }) // file upload annotations @MultipartConfig public class the Upload the extends the HttpServlet { public void the doPost (the HttpServletRequest Request, Response the HttpServletResponse) throws ServletException, IOException { // solve the Chinese garbled the response.setContentType ( "text / HTML; charset = UTF-. 8" ); Request.setCharacterEncoding ( "UTF-. 8" ); the PrintWriter OUT = response.getWriter (); File path= New new File ( "D: // tmp" ); IF (! {Path.exists ()) path.mkdir (); } Part Part = request.getPart ( "File" ); Out.println ( "size:" part.getSize + () + "<br>" ); // following the methods require tomcat7 get file name String = part.getHeader CD ( "the Content-Disposition" ); // taken of different types of files to decide if that String cd.substring = filename (cd.lastIndexOf ( "=") + 2, cd.length () -. 1 ); // above Tomcat8 only part. getSubmittedFileName () method can directly obtain // to upload files to the server String filePath = path.getPath() + File.separator + filename; part.write(filePath); System.out.println("File Upload : " + filePath); } }