Handling Multipart Requests in springMVC

Handling Multipart Requests in springMVC#

When handling forms, it is possible to receive a file.

Configuring the Multipart Resolver#

The resolver is a subclass of MultipartResolver, and usually using standardServletMultipartResolver is sufficient.

Simply add the following to the spring configuration file:

<bean class="org.springframework.web.multipart.support.StandardServletMultipartResolver"></bean>

@Bean
public MultiPartResolver getMultipartResoler(){
  return new StandardServletMultipartResolver();
}

Configuring Upload Requirements#

#web.xml

<servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
        <multipart-config>
            <location>D:\</location>
            <max-file-size>209152</max-file-size>
            <max-request-size>4194304</max-request-size>
        </multipart-config>
    </servlet>

This configuration is done inside the DispartcherServlet using the multipart-config tag.

Make sure the location is appropriate, otherwise an error will occur due to an invalid path after uploading the file.

Controller#

@RequestMapping(value = "/upload",method = RequestMethod.POST)
    @ResponseBody
    public String vallidateRegisterForm(@RequestPart("myfile")MultipartFile file) throws IOException {
      file.transferTo(new File(file.getOriginalFilename()));
      return "upload success.";
}

We are using @RequestPart("myfile")MultipartFile file, where MultipartFile can conveniently handle the uploaded file.

This is its interface definition:

public interface MultipartFile extends InputStreamSource {
    String getName();

    String getOriginalFilename();

    String getContentType();

    boolean isEmpty();

    long getSize();

    byte[] getBytes() throws IOException;

    InputStream getInputStream() throws IOException;

    void transferTo(File var1) throws IOException, IllegalStateException;
}

Testing the form#

<form class="fileform" action="/upload" method="post" enctype="multipart/form-data">
    <input type="file" name="myfile" value="">
    <input type="submit" name="" value="submit">
</form>