Send File as a parameter to a REST Service, from a

问题:

My Requirement is to send the file to the REST Service through one client. That service is going to process the file. I am using Jersey API for implementing this. But I have searched in many articles, there is no any information of how to pass the file from client side and how the REST service will retrieve the file... How to achieve this?

And I am not using the Servlets for Creating REST Service.

回答1:

Assuming you are using Jersey on both the client and server side, here is some code that you can extend:

Server side:

@POST
@Path("/")
@Produces(MediaType.TEXT_PLAIN)
@Consumes(MediaType.MULTIPART_FORM_DATA)
public Response uploadFile(final MimeMultipart file) {
    if (file == null)
        return Response.status(Status.BAD_REQUEST)
                .entity("Must supply a valid file").build();

    try {
        for (int i = 0; i < file.getCount(); i++) {
            System.out.println("Body Part: " + file.getBodyPart(i));
        }
        return Response.ok("Done").build();
    } catch (final Exception e) {
        return Response.status(Status.INTERNAL_SERVER_ERROR).entity(e)
                .build();
    }
}

The above code implements a resource method that accepts POST's of multipart (file) data. It also illustrates how you can iterate through all the individual body parts in the incoming (multipart) request.

Client:

final ClientConfig config = new DefaultClientConfig();
final Client client = Client.create(config);

final WebResource resource = client.resource(ENDPOINT_URL);

final MimeMultipart request = new MimeMultipart();
request.addBodyPart(new MimeBodyPart(new FileInputStream(new File(
        fileName))));

final String response = resource
    .entity(request, "multipart/form-data")
    .accept("text/plain")
    .post(String.class);

The above code simply attaches a file to a multipart request, and fires the request off to the server. For both client and server side code there is a reliance on the Jersey and JavaMail libraries. If you are using Maven, these can be pulled down with ease, with the following dependencies:

<dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-core</artifactId>
    <version>1.17</version>
</dependency>

<dependency> <!-- only on server side -->
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-server</artifactId>
    <version>1.14</version>
</dependency>

<dependency> <!-- only on client side -->
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-client</artifactId>
    <version>1.17</version>
</dependency>

<dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-json</artifactId>
    <version>1.17</version>
</dependency>

<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4.6</version>
</dependency>

Adjust the dependency versions as required

回答2:

Am I right by assuming, since its a MimeMultipart type, that I could not just send one, but multiple files or additional information maybe as String or whatever, on doing only one simple post, just by adding multiple MimeBodyParts containing the different files or whatever? for example like:

final MimeMultipart request = new MimeMultipart();
request.addBodyPart(new MimeBodyPart(new FileInputStream(new File(
    fileOne))), 0);
request.addBodyPart(new MimeBodyPart(new FileInputStream(new File(
    fileTwo))), 1);

etc.