How to return an image in Spring Boot controller and serve like a file system
<p>I've tried the various ways given in Stackoverflow, maybe I missed something.</p>

<p>I have an Android client (whose code I can't change) which is currently getting an image like this:</p>

<pre><code>HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
</code></pre>

<p>Where <code>url</code> is the location of the image (static resource on CDN). Now my Spring Boot API endpoint needs to behave like a file resource in the same way so that the same code can get images from the API (Spring boot version 1.3.3).</p>

<p>So I have this:</p>

<pre><code>@ResponseBody
@RequestMapping(value = "/Image/{id:.+}", method = RequestMethod.GET, consumes = MediaType.ALL_VALUE, produces = MediaType.IMAGE_JPEG_VALUE)
public ResponseEntity&lt;byte[]&gt; getImage(@PathVariable("id")String id) {
    byte[] image = imageService.getImage(id);  //this just gets the data from a database
    return ResponseEntity.ok(image);
}
</code></pre>

<p>Now when the Android code tries to get <code>http://someurl/image1.jpg</code> I get this error in my logs:</p>

<blockquote>
  <p>Resolving exception from handler [public
  org.springframework.http.ResponseEntity
  com.myproject.MyController.getImage(java.lang.String)]:
  org.springframework.web.HttpMediaTypeNotAcceptableException: Could not
  find acceptable representation</p>
</blockquote>

<p>Same error happens when I plug <code>http://someurl/image1.jpg</code> into a browser.</p>

<p>Oddly enough my tests check out ok:</p>

<pre><code>Response response = given()
            .pathParam("id", "image1.jpg")
            .when()
            .get("MyController/Image/{id}");

assertEquals(HttpStatus.OK.value(), response.getStatusCode());
byte[] array = response.asByteArray(); //byte array is identical to test image
</code></pre>

<p>How do I get this to behave like an image being served up in the normal way? (Note I can't change the content-type header that the android code is sending)</p>

<p><strong>EDIT</strong></p>

<p>Code after comments (set content type, take out <code>produces</code>):</p>

<pre><code>@RequestMapping(value = "/Image/{id:.+}", method = RequestMethod.GET, consumes = MediaType.ALL_VALUE)
public ResponseEntity&lt;byte[]&gt; getImage(@PathVariable("id")String id, HttpServletResponse response) {
    byte[] image = imageService.getImage(id);  //this just gets the data from a database
    response.setContentType(MediaType.IMAGE_JPEG_VALUE);
    return ResponseEntity.ok(image);
}
</code></pre>

<p>In a browser this just seems to give a stringified junk (byte to chars i guess). In Android it doesn't error, but the image doesn't show.</p>