spring boot setContentType 不工作

Question

我正在尝试在 spring-boot (1.2.2) 上返回一个图像
我应该如何设置内容类型？
以下都不适合我(意味着响应 header 根本不包含“内容类型” header ):

    @RequestMapping(value = "/files2/{file_name:.+}", method = RequestMethod.GET)
public ResponseEntity<InputStreamResource> getFile2(final HttpServletResponse response) throws IOException {
    InputStream is = //someInputStream...
    org.apache.commons.io.IOUtils.copy(is, response.getOutputStream());
    response.setContentType("image/jpeg");
    InputStreamResource inputStreamR = new InputStreamResource(is);
    return new ResponseEntity<>(inputStreamR, HttpStatus.OK);
}

@RequestMapping(value = "/files3/{file_name:.+}", method = RequestMethod.GET)
public HttpEntity<byte[]> getFile3() throws IOException {
    InputStream is = //someInputStream...
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.IMAGE_JPEG);
    return new HttpEntity<>(IOUtils.toByteArray(is), headers);
}

Answer 1

首先，您需要申请 @ResponseBody除了 @RequestMapping 的注释, 除非您使用的是 @RestController在类(class)级别，而不仅仅是 @Controller .另外，试试 produces @RequestMapping 的元素例如

@RequestMapping(value = "/files2/{file_name:.+}", method = RequestMethod.GET, produces = {MediaType.IMAGE_JPEG_VALUE})

这应该“缩小主要映射”并确保设置正确的内容类型。查看文档: http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#mvc-ann-requestmapping-produces