Servlet 3.0 improves some of the APIS, which greatly simplifies Java Web development. These include HttpServletRequest adding support for file uploads.
HttpServletRequest provides the following two methods to handle file uploads:
- Part getPart(String name); Get the file upload domain by name
- Collection getParts(); Get all file upload domains
Construct the form to upload the file
<form action="uploadServlet" method="post" enctype="multipart/form-data">Uploading files:<input type="file" name="file"/><br/>File Description:<input type="text" name="desc"/>
<input type="submit"/>
</form>
Copy the code
use
Annotate @webServlet + @multipartConfig on servlets that need to handle file uploads
@WebServlet("/uploadServlet")
@MultipartConfig
public class UploadServlet extends HttpServlet {}Copy the code
Can pass javax.mail. Servlet. HTTP. It. GetPart (String name) method for Part object
Javax.servlet.http.Part interface method:
| methods | role |
|---|---|
| InputStream getInputStream() throws IOException; | Get the uploaded input stream |
| String getContentType(); | Get the content-type field value of the multipart form |
| String getName(); | Gets the field name of the multipart form |
| String getSubmittedFileName(); | If the part is a file, return the file name; Otherwise, null |
| long getSize(); | Get the size of the part |
| void write(String fileName) throws IOException; | Write files |
| void delete() throws IOException; | |
| String getHeader(String name); | Gets the value of the specified header |
| Collection getHeaders(String name); | Get the full value of the header |
| Collection getHeaderNames(); | Get all the header names |
Note:
The getSubmittedFileName method may not get the file name correctly when testing in IE 10.
Internet Options > Security > Custom Levels > Others > Disable Include local directory paths when uploading files to the server