我从FTP下载文件,在内存中处理文件,然后将几个文件保存到同一FTP服务器时遇到问题。
我要实现的目标:我想下载csv文件(可以说1000行),将其拆分为较小的文件(每个文件100行),然后保存到其他目录中。
我成功连接到FTP,成功下载了filee并进行处理,但是我无法保存那些较小的文件。
码:
public boolean getFile1(final String filePath, final String fileName) {
String remoteFile = filePath + "/" + fileName;
BufferedReader reader = null;
try{
InputStream is = ftpClient.retrieveFileStream(remoteFile);
reader = new BufferedReader(new InputStreamReader(is));
String line;
String file ="";
int i = 1;
int max = 100;
int current = 0;
while((line = reader.readLine()) != null){
if(current < max){
file+=line+"\n";
current++;
}
else{
System.out.println("Else; File: " +file);
InputStream stream = new ByteArrayInputStream(file.getBytes(StandardCharsets.UTF_8.name()));
putFile(stream, "test", "MOCK_COPY"+i+".csv");
i++;
file = "";
current = 0;
file+=line+"\n";
}
}
if(!file.isEmpty()){
System.out.println("End File: " +file);
InputStream is2 = IOUtils.toInputStream(file, "UTF-8");
putFile(is2, "test", "MOCK_COPY"+i+".csv");
}
} catch (IOException e){
e.printStackTrace();
} finally {
try{
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return true;
}
public Boolean putFile(InputStream inputStream, final String filePath, final String fileName) throws IOException {
Long ts = System.currentTimeMillis();
String remoteFile = filePath + "/" + fileName;
System.out.println("Start uploading file");
// ftpClient.changeWorkingDirectory("test");
////this overwrites the existing file
// ftpClient.storeFile(remoteFile, inputStream);
//inputStream.close();
OutputStream outputStream = ftpClient.storeFileStream(remoteFile);
byte[] bytesIn = new byte[4096];
int read = 0;
while ((read = inputStream.read(bytesIn)) != -1) {
outputStream.write(bytesIn, 0, read);
}
inputStream.close();
outputStream.close();
System.out.println("The file is uploaded successfully in " + (System.currentTimeMillis() - ts) / 1000 + "s");
return true;
}
连接:
public void connectToServer(String server, String user, String pass, Integer port)
throws WebApplicationException {
port = port == null ? 21 : null;
server = server.replace("ftp://","");
try {
ftpClient = new FTPClient();
ftpClient.connect(server, port);
ftpClient.login(user, pass);
ftpClient.enterLocalPassiveMode();
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
System.out.println("Connected to ftp");
}
catch (IOException e) {
e.printStackTrace();
throw new WebApplicationException(Response.status(Response.Status.NOT_FOUND)
.entity("FTP error: " + e.getMessage()).type(MediaType.TEXT_PLAIN).build());
}
}
我从OutputStream获取了空指针异常(但是ftpCLient和remotefile不为空)
我观察到,如果我仅尝试使用该方法上传文件,一切都会很好。
有人知道发生了什么吗?
最佳答案
使用FTP协议,您无法通过同一连接同时下载和上传。
将下载和上传过程分开。
或打开两个连接,一个用于下载,另一个用于上载。
我并不是在说这是您遇到异常的根本原因。但这很有可能。即使不是这样,您的代码也无法正常工作,因此没有必要尝试将其修复为当前状态。