How to create an endpoint which takes a path, load the image and serve it to the client-CodePudding

I want to serve an image to a client by converting it to a byte but for some reason byteArrayOutputStream.toByteArray() is empty. I get a response status of 200 which means it is served. I looked at various documentations on reading an image file from a directory using BufferedImage and then converting BufferedImage to a byteArray from oracle

CodePudding user response：

You should just read the bytes of the file directly rather than using more methods than necessary. This can be done with the class java.nio.file.Files.

byte[] contentBytes = Files.readAllBytes(path); //Throws IOException

CodePudding user response：

Probably the file extension is not getting set properly.

You can create a new method to get the file extension or you can use FilenameUtils.getExtension from Apache Commons IO.

public static Optional<String> getExtensionByStringHandling(String filename) {
    return Optional.ofNullable(filename)
            .filter(f -> f.contains("."))
            .map(f -> f.substring(filename.lastIndexOf(".")   1));
}

then change your ImageIO to take this file extention.

String fileExtention= getExtensionByStringHandling(file.getName()).orElseThrow(()->new RuntimeException("File extension not found"));
ImageIO.write(image, fileExtention, byteArrayOutputStream);