英文:
Java Apache FTPClient most downloaded files are empty or missing
问题
这是我的代码，应该能够将整个FTP目录下载到本地文件夹。它确实可以正常运行，但大多数文件的大小为0KB。只有JSON文件似乎包含了所有数据。
我尝试过的方法：
- 使用
client.setFileType("FTP.BINARY_FILE_TYPE");更改FTP文件类型。 - 使用
OutputStream替代FileOutputStream。
代码部分：
public static void copyFolder(File destination, FTPFile sourceFile, FTPClient ftpClient) throws IOException{
if (!sourceFile.isDirectory()) {
// 复制文件
File downloadFile = new File(destination + "/" + sourceFile.getName());
String remoteFile = sourceFile.getName();
FileOutputStream outputStream = new FileOutputStream(downloadFile);
System.out.println(remoteFile);
System.out.println(downloadFile.getPath());
boolean success = ftpClient.retrieveFile(remoteFile, outputStream);
if(success) {
System.out.println("已检索 " + remoteFile);
}
outputStream.close();
}else{
// 遍历子目录
ftpClient.changeWorkingDirectory(ftpClient.printWorkingDirectory() + "/" + sourceFile.getName());
System.out.println(ftpClient.printWorkingDirectory());
FTPFile[] contents = ftpClient.listFiles(ftpClient.printWorkingDirectory());
File newDest = new File(destination + "/" + sourceFile.getName());
if(!newDest.exists()){
newDest.mkdir();
}
for(FTPFile file : contents){
copyFolder(newDest, file, ftpClient);
}
return;
}
}
如何正确进行传输？
在同一台计算机上尝试下载时，会在文件下载期间和之间多次失去连接。而且似乎只下载了少数文件。我将更改问题的标题，使其更具体。
由于某种原因，只有两个文件被复制 - https://pastebin.com/XNWqRMDj 它们并不为空。
英文:
This is my code that is supposed to download entire FTP directory to a local folder. It does it well, but most of the files are 0KB in size. Only JSON files seem to contain all their data.
Things I tried:
- Changing FTP file type with
client.setFileType("FTP.BINARY_FILE_TYPE"); - Using
OutputStreaminstead ofFileOutputStream
Code:
public static void copyFolder(File destination, FTPFile sourceFile, FTPClient ftpClient) throws IOException{
if (!sourceFile.isDirectory()) {
//copy file
File downloadFile = new File(destination + "/"+ sourceFile.getName());
String remoteFile = sourceFile.getName();
FileOutputStream outputStream = new FileOutputStream(downloadFile);
System.out.println(remoteFile);
System.out.println(downloadFile.getPath());
boolean success = ftpClient.retrieveFile(remoteFile, outputStream);
if(success) {
System.out.println("Retrieved " + remoteFile);
}
outputStream.close();
}else{
//loop through a subdirectory
ftpClient.changeWorkingDirectory(ftpClient.printWorkingDirectory() + "/" + sourceFile.getName());
System.out.println(ftpClient.printWorkingDirectory());
FTPFile[] contents = ftpClient.listFiles(ftpClient.printWorkingDirectory());
File newDest = new File(destination + "/" + sourceFile.getName());
if(!newDest.exists()){
newDest.mkdir();
}
for(FTPFile file : contents){
copyFolder(newDest, file, ftpClient);
}
return;
}
}
How to get the transfer correctly?
Trying to download it on the same computer ended with losing connection a few times - between and during file downloads. Also it seems that few files are downloaded. I will change the title of question to be more specific.
Only two files are being copied for some reason – https://pastebin.com/XNWqRMDj They are not empty.
答案1
得分: 0
问题在于你的changeWorkingDirectory调用。它大多数情况下都失败。
ftpClient.changeWorkingDirectory(ftpClient.printWorkingDirectory() + "/" + sourceFile.getName());
应改为：
ftpClient.changeWorkingDirectory(destination + "/" + sourceFile.getName());
要获取Java中下载FTP文件夹的完整可工作代码，请参阅：
https://stackoverflow.com/q/50398695/850848
英文:
The problem is your changeWorkingDirectory call. It's failing most of the time.
ftpClient.changeWorkingDirectory(ftpClient.printWorkingDirectory() + "/" + sourceFile.getName());
It should be:
ftpClient.changeWorkingDirectory(destination + "/" + sourceFile.getName());
For a complete working code for downloading FTP folders in Java, see:
https://stackoverflow.com/q/50398695/850848
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论