当outputBuffer bytesWritten<时，响应无法返回图像. 8kb的 [英] Response fails to return image when outputBuffer bytesWritten < 8kb

问题描述

在SpringBoot应用程序中，我尝试通过以下方式通过Response对象的outputBuffer返回图像:

Within a SpringBoot app, I am attempting to return images via a Response object's outputBuffer, via:

try {
    response.setContentType("image/png");
    InputStream in = new FileInputStream(pathToFile);
    IOUtils.copy(in, response.getOutputStream());

}
catch (Exception e){
    ...
}

这很好，除非图像小于8kb ，在这种情况下，它什么也不会返回.

This works fine, unless the image is less than 8kb, in which case it just returns nothing.

谁能告诉我为什么小于8kb的原因导致响应实际上返回零数据(并且-至关重要的-如何解决此问题)?

Can anyone tell me why being less than 8kb would cause the Response to actually return zero data (and - crucially - how to remedy this)?

推荐答案

我已经通过在标头中显式设置内容长度来解决它:

I've solved it by setting the content length explicitly in the header:

File actualFile = new File(pathToFile);
if (actualFile.exists()){
    try {
        response.setContentType("image/png");
        response.setHeader("Content-Length", String.valueOf(actualFile.length()));
        InputStream in = new FileInputStream(pathToFile);
        IOUtils.copy(in, response.getOutputStream());
    }
    catch (Exception e){
        ...
    }
}

我想如果它的内容小于8kb，我不希望不知道内容的大小.

I guess it didn't like not knowing the size of the content if it was below 8kb.

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