英文:
Send SFTP file from database without actually creating a file
问题
我想从数据库中发送一些数据。目前我们的SFTP设置如下（使用apache commons vsf2库）。
try (StandardFileSystemManager manager = new StandardFileSystemManager()) {
File file = generateFileFromDatabase();
manager.init();
FileSystemOptions opts = new FileSystemOptions();
SftpFileSystemConfigBuilder.getInstance().setStrictHostKeyChecking(
opts, "no");
SftpFileSystemConfigBuilder.getInstance().setUserDirIsRoot(opts, true);
SftpFileSystemConfigBuilder.getInstance().setTimeout(opts, 10000);
// Create local file object
FileObject localFile = manager.resolveFile(file.getAbsolutePath());
// Create remote file object
FileObject remoteFile = manager.resolveFile(sftpUri, opts);
// Copy local file to the SFTP server
remoteFile.copyFrom(localFile, Selectors.SELECT_SELF);
} catch (Exception ex) {
ex.printStackTrace();
}
然而，generateFileFromDatabase() 函数通过调用 new 关键字来工作，就像这样：
return new File();
我不想这样，因为每次调用 generateFileFromDatabase() 都会在文件系统中保存一个新文件。有没有一种方法可以生成 File()，而不将其保存到文件目录中？
英文:
I want to send some data from the database. Currently our SFTP is set up like so (using the apache commons vsf2 library).
try(StandardFileSystemManager manager = new StandardFileSystemManager())
File file = generateFileFromDatabase();
manager.init();
FileSystemOptions opts = new FileSystemOptions();
SftpFileSystemConfigBuilder.getInstance().setStrictHostKeyChecking(
opts, "no");
SftpFileSystemConfigBuilder.getInstance().setUserDirIsRoot(opts, true);
SftpFileSystemConfigBuilder.getInstance().setTimeout(opts, 10000);
// Create localfile object
FileObject localFile = manager.resolveFile(file.getAbsolutePath());
// Create remote file object
FileObject remoteFile = manager.resolveFile(sftpUri, opts);
// Copy local file to sftp server
remoteFile.copyFrom(localFile, Selectors.SELECT_SELF);
} catch (Exception ex) {
ex.printStackTrace();
}
However, generateFileFromDatabase() works by invoking the new keyword, as in
return new File();
I don't want this, because this saves a new file in the file system every time generateFileFromDatabase() is called. Is there a way to generate a File() without saving it to the file directory?
答案1
得分: 0
只需使用以下代码：
OutputStream os = remoteFile.getContent().getOutputStream();
然后像处理本地文件一样，在循环中写入数据。
对于读取缓慢/大文件且连接时间长的情况，可能需要预先生成数据块并以多次追加的方式写入。
英文:
Just use
OutputStream os = remoteFile.getContent().getOutputStream();
and then write In a loop to it, just like you would with a local file.
This might be a problem for slow reading/large transfers with long open connections. In that case you might need to pre-produce chunks and write them in multiple appends.
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