java使用apache commons连接ftp修改ftp文件名失败原因
作者：朋也
这篇文章主要介绍了java使用apache commons连接ftp修改ftp文件名失败原因解析，本文给大家介绍的非常详细，具有一定的参考借鉴价值,需要的朋友可以参考下
今天被ftp上中文名修改坑了好久
项目用的是 apache commons 里的 FtpClient 实现的对ftp文件的上传下载操作，今天增加了业务要修改ftp上的文件名，然后就一直的报错，问题是它修改名字的方法只返回一个boolean，没有异常，这就很蛋疼了，找了好久才发现是中文的名字的原因
改名
直接上代码
package net.codejava.ftp;
import java.io.IOException;
import org.apache.commons.net.ftp.FTPClient;
public class FTPRenamer {
public static void main(String[] args) {
String server = "www.ftpserver.com";
int port = 21;
String user = "username";
String pass = "password";
FTPClient ftpClient = new FTPClient();
try {
ftpClient.connect(server, port);
ftpClient.login(user, pass);
// renaming directory
String oldDir = "/photo";
String newDir = "/photo_2012";
boolean success = ftpClient.rename(oldDir, newDir);
if (success) {
System.out.println(oldDir + " was successfully renamed to: "
+ newDir);
} else {
System.out.println("Failed to rename: " + oldDir);
}
// renaming file
String oldFile = "/work/error.png";
String newFile = "/work/screenshot.png";
success = ftpClient.rename(oldFile, newFile);
if (success) {
System.out.println(oldFile + " was successfully renamed to: "
+ newFile);
} else {
System.out.println("Failed to rename: " + oldFile);
}
ftpClient.logout();
ftpClient.disconnect();
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (ftpClient.isConnected()) {
try {
ftpClient.logout();
ftpClient.disconnect();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
}
如果修改的名字里没有中文，用上面的代码就够了，但如果有中文就要对文件名进行转码了，转码代码如下
// renaming file
String oldFile = "/work/你好.png";
String newFile = "/work/世界.png";
success = ftpClient.rename(
new String(oldFile.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1),
new String(newFile.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1)
);
这样再修改名字就没有问题了
顺便记录一下上传、下载、删除、检查文件是否存在， 同样的，如果有中文名，最好先转一下码再进行操作
上传
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
/**
* A program that demonstrates how to upload files from local computer
* to a remote FTP server using Apache Commons Net API.
* @author www.codejava.net
*/
public class FTPUploadFileDemo {
public static void main(String[] args) {
String server = "www.myserver.com";
int port = 21;
String user = "user";
String pass = "pass";
FTPClient ftpClient = new FTPClient();
try {
ftpClient.connect(server, port);
ftpClient.login(user, pass);
ftpClient.enterLocalPassiveMode();
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
// APPROACH #1: uploads first file using an InputStream
File firstLocalFile = new File("D:/Test/Projects.zip");
String firstRemoteFile = "Projects.zip";
InputStream inputStream = new FileInputStream(firstLocalFile);
System.out.println("Start uploading first file");
boolean done = ftpClient.storeFile(firstRemoteFile, inputStream);
inputStream.close();
if (done) {
System.out.println("The first file is uploaded successfully.");
}
// APPROACH #2: uploads second file using an OutputStream
File secondLocalFile = new File("E:/Test/Report.doc");
String secondRemoteFile = "test/Report.doc";
inputStream = new FileInputStream(secondLocalFile);
System.out.println("Start uploading second file");
OutputStream outputStream = ftpClient.storeFileStream(secondRemoteFile);
byte[] bytesIn = new byte[4096];
int read = 0;
while ((read = inputStream.read(bytesIn)) != -1) {
outputStream.write(bytesIn, 0, read);
}
inputStream.close();
outputStream.close();
boolean completed = ftpClient.completePendingCommand();
if (completed) {
System.out.println("The second file is uploaded successfully.");
}
} catch (IOException ex) {
System.out.println("Error: " + ex.getMessage());
ex.printStackTrace();
} finally {
try {
if (ftpClient.isConnected()) {
ftpClient.logout();
ftpClient.disconnect();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
下载
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
/**
* A program demonstrates how to upload files from local computer to a remote
* FTP server using Apache Commons Net API.
* @author www.codejava.net
*/
public class FTPDownloadFileDemo {
public static void main(String[] args) {
String server = "www.myserver.com";
int port = 21;
String user = "user";
String pass = "pass";
FTPClient ftpClient = new FTPClient();
try {
ftpClient.connect(server, port);
ftpClient.login(user, pass);
ftpClient.enterLocalPassiveMode();
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
// APPROACH #1: using retrieveFile(String, OutputStream)
String remoteFile1 = "/test/video.mp4";
File downloadFile1 = new File("D:/Downloads/video.mp4");
OutputStream outputStream1 = new BufferedOutputStream(new FileOutputStream(downloadFile1));
boolean success = ftpClient.retrieveFile(remoteFile1, outputStream1);
outputStream1.close();
if (success) {
System.out.println("File #1 has been downloaded successfully.");
}
// APPROACH #2: using InputStream retrieveFileStream(String)
String remoteFile2 = "/test/song.mp3";
File downloadFile2 = new File("D:/Downloads/song.mp3");
OutputStream outputStream2 = new BufferedOutputStream(new FileOutputStream(downloadFile2));
InputStream inputStream = ftpClient.retrieveFileStream(remoteFile2);
byte[] bytesArray = new byte[4096];
int bytesRead = -1;
while ((bytesRead = inputStream.read(bytesArray)) != -1) {
outputStream2.write(bytesArray, 0, bytesRead);
}
success = ftpClient.completePendingCommand();
if (success) {
System.out.println("File #2 has been downloaded successfully.");
}
outputStream2.close();
inputStream.close();
} catch (IOException ex) {
System.out.println("Error: " + ex.getMessage());
ex.printStackTrace();
} finally {
try {
if (ftpClient.isConnected()) {
ftpClient.logout();
ftpClient.disconnect();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
删除
import java.io.IOException;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;
public class FTPDeleteFileDemo {
public static void main(String[] args) {
String server = "www.myserver.com";
int port = 21;
String user = "user";
String pass = "pass";
FTPClient ftpClient = new FTPClient();
try {
ftpClient.connect(server, port);
int replyCode = ftpClient.getReplyCode();
if (!FTPReply.isPositiveCompletion(replyCode)) {
System.out.println("Connect failed");
return;
}
boolean success = ftpClient.login(user, pass);
if (!success) {
System.out.println("Could not login to the server");
return;
}
String fileToDelete = "/repository/video/cool.mp4";
boolean deleted = ftpClient.deleteFile(fileToDelete);
if (deleted) {
System.out.println("The file was deleted successfully.");
} else {
System.out.println("Could not delete the file, it may not exist.");
}
} catch (IOException ex) {
System.out.println("Oh no, there was an error: " + ex.getMessage());
ex.printStackTrace();
} finally {
// logs out and disconnects from server
try {
if (ftpClient.isConnected()) {
ftpClient.logout();
ftpClient.disconnect();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
检查文件/文件夹是否存在
package net.codejava.ftp;
import java.io.IOException;
import java.io.InputStream;
import java.net.SocketException;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;
/**
* This program demonstrates how to determine existence of a specific
* file/directory on a remote FTP server.
* @author www.codejava.net
*
*/
public class FTPCheckFileExists {
private FTPClient ftpClient;
private int returnCode;
/**
* Determines whether a directory exists or not
* @param dirPath
* @return true if exists, false otherwise
* @throws IOException thrown if any I/O error occurred.
*/
boolean checkDirectoryExists(String dirPath) throws IOException {
ftpClient.changeWorkingDirectory(dirPath);
returnCode = ftpClient.getReplyCode();
if (returnCode == 550) {
return false;
}
return true;
}
/**
* Determines whether a file exists or not
* @param filePath
* @return true if exists, false otherwise
* @throws IOException thrown if any I/O error occurred.
*/
boolean checkFileExists(String filePath) throws IOException {
InputStream inputStream = ftpClient.retrieveFileStream(filePath);
returnCode = ftpClient.getReplyCode();
if (inputStream == null || returnCode == 550) {
return false;
}
return true;
}
/**
* Connects to a remote FTP server
*/
void connect(String hostname, int port, String username, String password)
throws SocketException, IOException {
ftpClient = new FTPClient();
ftpClient.connect(hostname, port);
returnCode = ftpClient.getReplyCode();
if (!FTPReply.isPositiveCompletion(returnCode)) {
throw new IOException("Could not connect");
}
boolean loggedIn = ftpClient.login(username, password);
if (!loggedIn) {
throw new IOException("Could not login");
}
System.out.println("Connected and logged in.");
}
/**
* Logs out and disconnects from the server
*/
void logout() throws IOException {
if (ftpClient != null && ftpClient.isConnected()) {
ftpClient.logout();
ftpClient.disconnect();
System.out.println("Logged out");
}
}
/**
* Runs this program
*/
public static void main(String[] args) {
String hostname = "www.yourserver.com";
int port = 21;
String username = "your_user";
String password = "your_password";
String dirPath = "Photo";
String filePath = "Music.mp4";
FTPCheckFileExists ftpApp = new FTPCheckFileExists();
try {
ftpApp.connect(hostname, port, username, password);
boolean exist = ftpApp.checkDirectoryExists(dirPath);
System.out.println("Is directory " + dirPath + " exists? " + exist);
exist = ftpApp.checkFileExists(filePath);
System.out.println("Is file " + filePath + " exists? " + exist);
} catch (IOException ex) {
ex.printStackTrace();
} finally {
try {
ftpApp.logout();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
参考
https://www.codejava.net/java-se/ftp/how-to-start-ftp-programming-with-java
总结
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