使用Java API从Google云端硬盘下载文件

我正在使用Java API来创建应用程序.但是,我无法解决从驱动器下载文件的问题.

我正在尝试使用Google Developer’s页面上提供的功能. (下方链接)

https://developers.google.com/drive/manage-downloads

但是,没有明确提到如何为特定文件获取/生成downloadURI.而且我也很困惑如何使用downloadURI下载文件.

我使用以下功能 –

private static InputStream downloadFile(Drive service, File file) 
{
    if (file.getDownloadUrl() != null && file.getDownloadUrl().length() > 0) 
    {
      try 
      {
        HttpResponse resp = service.getRequestFactory().buildGetRequest
                     (new GenericUrl(file.getDownloadUrl())).execute();
        return resp.getContent();
      }
      catch (IOException e) 
      {
        e.printStackTrace();
        return null;
      }
    } 
    else 
    {
     return null;
    }
 }

在这里,我无法获得该文件应该是该函数的输入参数.
请帮帮我.

解决方法:

这就是我做到的.
我没有下载文档,而是下载给定文档的所有修订版.所以逻辑是一样的.

    private void downloadRevisions(final RevisionList revisions,
            final Drive service) {

        Thread thread = new Thread(new Runnable(){
            @Override
            public void run() {
                try {

                    //TODO for debugging
                    int i = 0;

                    for (Revision revision : revisions.getItems()) {

                        System.out.println("Thread running: " + i);
                        if (revision.getExportLinks() != null
                                && revision.getExportLinks().get("text/plain") != null 
                                && revision.getExportLinks().get("text/plain").length()  > 0) {
                            HttpResponse resp = service
                                    .getRequestFactory()
                                    .buildGetRequest(
                                            new GenericUrl(revision
                                                    .getExportLinks().get("text/plain")))
                                    .execute();

                            //InputStream inputStream = resp.getContent();

                            //File Name
                            String revisionFileName = docId+"_"+revision.getId()+"_"+revision.getModifiedDate();
                            FileOutputStream outputstream = new FileOutputStream(new java.io.File(revisionFileDir, revisionFileName));
                            IOUtils.copy(resp.getContent(), outputstream,true);
                            outputstream.close();

                            // writeToFile(inputStream);
                            System.out.println("downloading: " + revisionFileName);
                        }

                        //TODO for debugging
                        i++;
                    }



                    System.out.println("Downloading Done. Document Id: "+docId);

                } catch (IOException e) {
                    Log.info("WriteToFile Fail", e.toString());
                    e.printStackTrace();
                }finally{
                    //if( doneFW !=null)
                    //  doneFW.close();
                }
            }
        });
        thread.start();
    }

标签：java,google-drive-api
来源： https://codeday.me/bug/20191008/1874111.html