How can I get info from a html form in JAVA without servlet?

Question

I am uploading file by HTML form:

<form class="formulario" action="validatorKenken.cgi" method="GET">
                    <input type="file" name="xml" accept="*.xml"> <br/>
                    <input type="submit">   
</form>

Java file is called for CGI File which is called by the form. I need to save the file, which I am uploading, at server.

I have seen solutions using servlet but I have problems to compile it because the import javax.servlet is not exist.

I am using Java 1.7.0_101

Thank you!

Answer 1

The script will have the CONTENT_TYPE environment variable set to either application/x-www-form-urlencoded or multipart/form-data . The latter is usually used only for forms with <input type=file> controls. Either way, the request body will be in the standard input, which Java will inherit, along with all environment variables.

Since your form has a file field, the content type will be multipart/form-data . The body will contain a multipart MIME message.

Parsing a multipart MIME message is an order of magnitude easier if you use a JavaMail implementation, as you can make use of its MimeMultipart class, and its related classes:

Path saveDir = Paths.get("/home/enery93/Downloads");

// id or name attribute of HTML <input type='file'> element
String fileInputControlName = "file";

Path formDataFile = Files.createTempFile(null, null);
Files.copy(System.in, formDataFile, StandardCopyOption.REPLACE_EXISTING);

MimeMultipart formData = new MimeMultipart(
    new FileDataSource(formDataFile.toFile()));

int count = formData.getCount();
for (int i = 0; i < count; i++) {
    BodyPart part = formData.getBodyPart(i);

    // See HTML 4.01 spec, section 17.13.4 at
    // https://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.2
    ContentDisposition disposition =
        new ContentDisposition(part.getDisposition());
    String name = disposition.getParameter("name");

    if (fileInputControlName.equals(name)) {
        Path saveFile = saveDir.resolve(part.getFileName());
        try (InputStream content = part.getInputStream()) {
            Files.copy(content, saveFile);
        }
        break;
    }
}

Files.delete(formDataFile);

As of this writing, a complete javax.mail.jar is available at http://java.net/projects/javamail/downloads/download/javax.mail.jar .

If you are unable or unwilling to use JavaMail, you'll have to parse the multipart content yourself, which is not pleasant.