Java 错误：无法使用google cloud StorageOptions for SignUrl加载PDF文档

我正在尝试使用google cloud SignUrl从Web API获取PDF文档，并希望在应用程序中显示。获取“错误：无法加载PDF文档”

我跟随signurl:-

public com.google.cloud.storage.Storage getStorage() {
    if(storage == null) {
        synchronized (lock) {
            if(storage == null) {
                storage = StorageOptions.getDefaultInstance().getService();
            }
        }
    }
    return storage;
}


  //   -- TRY other way to get pdf file.
public String getSignedUrl(String fileName) throws IOException {
    BlobId blobId = BlobId.of(gcsBucket, remotePath);
    BlobInfo blobInfo = BlobInfo.newBuilder(blobId)
            /*.setContentType("application/doc")*/
            /*.setContentType("application/pdf")*/
            /*.setContentType("application/octet-stream")*/
            .build();
    URL url =  cloudStorageFactory.getStorage().signUrl(blobInfo,ttlMinutes, TimeUnit.MINUTES, SignUrlOption.httpMethod(HttpMethod.GET)
    //                    ,SignUrlOption.withContentType()
    );
    return url.toString();
}

下面的代码可以很好地用于图像文件

我试着用代码注释。 它的代码获取所有文件和pdf文件的signurl，但我无法弄清楚它是如何获取pdf文件以供查看的

请检查我的密码：

控制器类：-

class ControllerClass{
    public Result show(String fileName) throws IOException {
        return redirect(mModelService.getSignedUrl(fileName));
        //   -- TRY other way to get pdf file.
        //return redirect(mModelService.getSignedUrl(userId,fileName));
        //                .withHeader("Content-Type","application/pdf");
        //                .as("application/octet-stream");
    }
}

获取签名Url:-

public String getSignedUrl(String fileName) throws IOException {
String remotePath = filePath(fileName);
BlobId blobId = BlobId.of("gcsBucket", remotePath);
    Blob blob =  getStorage().get(blobId);
    if(blob != null && blob.exists()){
        URL url = blob.signUrl(ttlMinutes, TimeUnit.MINUTES, SignUrlOption.httpMethod(HttpMethod.GET)
        );
        return url.toString();
}

获取存储：-

public com.google.cloud.storage.Storage getStorage() {
    if(storage == null) {
        synchronized (lock) {
            if(storage == null) {
                storage = StorageOptions.getDefaultInstance().getService();
            }
        }
    }
    return storage;
}


  //   -- TRY other way to get pdf file.
public String getSignedUrl(String fileName) throws IOException {
    BlobId blobId = BlobId.of(gcsBucket, remotePath);
    BlobInfo blobInfo = BlobInfo.newBuilder(blobId)
            /*.setContentType("application/doc")*/
            /*.setContentType("application/pdf")*/
            /*.setContentType("application/octet-stream")*/
            .build();
    URL url =  cloudStorageFactory.getStorage().signUrl(blobInfo,ttlMinutes, TimeUnit.MINUTES, SignUrlOption.httpMethod(HttpMethod.GET)
    //                    ,SignUrlOption.withContentType()
    );
    return url.toString();
}

---

您不知道如何将PDF文件从控制器发送到视图？获取文件时遇到问题。或者两者都有？这个错误是从哪里来的？什么是错误堆栈？获取文件时。首先，文件是否存在？您正在使用哪个Java IO功能访问它？是的，文件存在。它不是用于存储临时文件的任何IO，它的代码使用注册url，直接显示文件的有效显示请参见此行：-url url url=cloudStorageFactory.getStorage（）.signUrl（blobInfo，ttlMinutes，TimeUnit.MINUTES，SignUrlOption.httpMethod（httpMethod.GET）；