jsch 包 sftp下载文件只能下载16Kb超出就下不了了请问是扫码问题

/*传入目标文件*/
SftpATTRS attr = sftp.stat(directory+downloadFile);
/*文件大小*/
long fileSize = attr.getSize();
System.out.println("the file length is:"+fileSize);
//outputfile = new FileOutputStream(file);

sftp.get(directory+downloadFile, filepath, new FileProgressMonitor(fileSize));
//sftp.get(directory+downloadFile, filepath);
flag = true;

https://blog.csdn.net/sand_clock/article/details/79042082