您可以将HTML图像标记的src属性设置为控制器方法吗？ [英] Can you set the src attribute of an HTML image tag to a controller method?

问题描述

我知道你可以这样做

<img src="http://some_svg_on_the_web" />

但如果我的控制器方法用 @ResponseBody

But what if I have a controller method annotated with @ResponseBody

@RequestMapping(value="getSVG")
public @ResponseBody String getSVG(HttpServletRequest request, HttpServerletResponse response) {
    String SVG = // build the SVG XML as a string

    return SVG;
}

我可以说

<img src="/getSVG" />

我已经测试过，控制器肯定被击中，但页面上没有显示图像。

I have tested and the controller is definitely being hit but no image is being shown on the page.

推荐答案

我认为问题是Spring将默认内容类型设置为 application / octet-stream ，浏览器无法读取您的XML。相反，您需要通过 HttpServerletResponse 或使用Spring的<$ c $实际设置 Content-Type 标头。 c> ResponseEntity 。

I believe the problem is Spring is setting the default content type to application/octet-stream and the browser can't read your XML as that. Instead, you need to actually set the Content-Type header, either through the HttpServerletResponse or with Spring's ResponseEntity.

@RequestMapping(value="getSVG")
public @ResponseBody ResponseEntity<String> getSVG(HttpServletRequest request, HttpServerletResponse response) {
    String SVG = // build the SVG XML as a string
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.valueOf("image/svg+xml"));
    ResponseEntity<String> svgEntity = new ResponseEntity<String>(svg, headers, HttpStatus.OK);
    return svgEntity;
}

您将XML作为的事实字符串并不重要，您可以使用 getBytes（）来制作内容 byte [] 。您还可以使用 Resource 类让Spring直接从类路径或文件系统资源中获取字节。你会相应地参数化 ResponseEntity （有许多支持的类型）。

The fact that the you have the XML as a String doesn't really matter, you could've used getBytes() to make the content byte[]. You can also use the Resource class to have Spring get the bytes directly from a classpath or file system resource. You would parameterize ResponseEntity accordingly (there are a number of supported types).

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