Spring Web MVC：如何在视图类而不是控制器中使用ResponseEntity？

Question

Using Spring Web MVC, I would like to use a ResponseEntity to send bytes back to the client.

For example, I could do this:

@RequestMapping(value = "/getMyBytes", method = RequestMethod.GET)
public ResponseEntity< byte[] > handleGetMyBytesRequest()
{
    // Get bytes from somewhere...
    byte[] byteData = ....

    HttpHeaders responseHeaders = new HttpHeaders();
    responseHeaders.setContentType( MediaType.IMAGE_PNG );
    responseHeaders.setContentLength( byteData.length );

    return new ResponseEntity< byte[] >( byteData, 
        responseHeaders, HttpStatus.OK );
}

But now the controller itself decides, how the data will be presented to the client. Shouldn't that not be the job of the view?

So my question is, when I have this view class:

public class DemoView extends AbstractView
{
    @Override
    protected void renderMergedOutputModel( Map< String, Object > model, 
            HttpServletRequest request, HttpServletResponse response ) throws Exception
    {
        bytes[] byteData = model.get( "byteData" );

        // ???
    }
}

How must the view code look like, when I want to use a ResponseEntity there?

Or does it make no sense to use ResponseEntity in the view class, and if yes, why?

Thanks a lot for your help!

Answer 1

In your AbstractView you can simply use the HttpServletResponse object to set the HTTP response status and write the byte[] array to the output stream:

response.setStatus(status);
response.getOutputStream().write(byteData);