我尝试了以下方法：

filePath = sourcePath + "ash.jpg";

byte[] fileContent = FileUtils.readFileToByteArray(new File(filePath));
String encodedString = Base64.getEncoder().encodeToString(fileContent);

imagePayload = HttpRequest.BodyPublishers.ofString(encodedString)

def url='https://graph.microsoft.com/v1.0/users/<myuser>/photo/$value';

HttpClient httpClient = HttpClient.newBuilder()
                        .version(HttpClient.Version.HTTP_2)
                        .build();

HttpRequest request = HttpRequest.newBuilder()
                      .uri(URI.create(url))
                      .method("PUT",imagePayload)
                      .header("Content-Type", "image/jpeg")
                      .header("Authorization", "Bearer " + token)
                      .build();

回报告诉我：
发生内部服务器错误。操作失败。您选择的文件不是图像。请选择其他文件。
我猜有效载荷是错的，但他到底期望什么呢？ms-graph文档说明它应该是jpeg图像的二进制表示
包括以下内容：

filePath = sourcePath + "ash.jpg";

file = new File(filePath);

BufferedImage image = ImageIO.read(file);

ByteArrayOutputStream b = new ByteArrayOutputStream();
ImageIO.write(image, "jpg", b);

byte[] jpgByteArray = b.toByteArray();

StringBuilder sb = new StringBuilder();
for (byte by : jpgByteArray)
    sb.append(Integer.toBinaryString(by & 0xFF));

imagePayloadAsString = sb.toString();

imagePayload = HttpRequest.BodyPublishers.ofString(imagePayloadAsString)

我用os和1s得到二进制字符串，但是webservice仍然说我的文件不是图像。我必须承认我很困惑