前端传递Base64字符串，后端转流存入OSS

工具类

public static BufferedInputStream base64Convert(String base64) {
        // 解码
        base64 = base64.split(",")[1];
        try {
            byte[] buffer = Base64.getMimeDecoder().decode(base64);
            for (int i = 0; i < buffer.length; i++) {
                if (buffer[i] < 0) {
                    buffer[i] += 256;
                }
            }
            // 生成流
            return new BufferedInputStream(new ByteArrayInputStream(buffer));
        } catch (Exception e) {
            log.info("base64解码失败");
            throw new RuntimeException(e);
        }
    }