安卓开发连接FTP服务器：FTP/SFTP连接

在Android应用程序中，有时需要连接到FTP或SFTP服务器以上传、下载或管理文件，以下是一些关于如何在Android应用中实现FTP和SFTP连接的详细信息。

使用Apache Commons Net库进行FTP连接

要在Android应用程序中实现FTP连接，可以使用Apache Commons Net库，需要在项目的build.gradle文件中添加以下依赖项：

 dependencies {     implementation 'commonsnet:commonsnet:3.8.0' } 

可以使用以下代码片段建立FTP连接并执行基本操作（如列出目录、上传和下载文件）：

 import org.apache.commons.net.ftp.FTP; import org.apache.commons.net.ftp.FTPClient; import java.io.IOException; public class FTPConnection {     private String server;     private int port;     private String user;     private String password;     private FTPClient ftpClient;     public FTPConnection(String server, int port, String user, String password) {         this.server = server;         this.port = port;         this.user = user;         this.password = password;     }     public void connect() throws IOException {         ftpClient = new FTPClient();         ftpClient.connect(server, port);         ftpClient.login(user, password);         ftpClient.enterLocalPassiveMode();     }     public void disconnect() throws IOException {         if (ftpClient.isConnected()) {             ftpClient.logout();             ftpClient.disconnect();         }     }     public void listFiles() throws IOException {         String[] files = ftpClient.listNames();         for (String file : files) {             System.out.println(file);         }     }     public void uploadFile(String localPath, String remotePath) throws IOException {         ftpClient.storeFile(remotePath, new FileInputStream(localPath));     }     public void downloadFile(String remotePath, String localPath) throws IOException {         FileOutputStream fos = new FileOutputStream(localPath);         ftpClient.retrieveFile(remotePath, fos);         fos.close();     } } 

使用JSch库进行SFTP连接

要在Android应用程序中实现SFTP连接，可以使用JSch库，需要在项目的build.gradle文件中添加以下依赖项：

 dependencies {     implementation 'com.jcraft:jsch:0.1.55' } 

可以使用以下代码片段建立SFTP连接并执行基本操作（如列出目录、上传和下载文件）：

 import com.jcraft.jsch.ChannelSftp; import com.jcraft.jsch.JSch; import com.jcraft.jsch.Session; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class SFTPConnection {     private String host;     private int port;     private String user;     private String password;     private ChannelSftp channelSftp;     public SFTPConnection(String host, int port, String user, String password) throws Exception {         this.host = host;         this.port = port;         this.user = user;         this.password = password;     }     public void connect() throws Exception {         JSch jsch = new JSch();         Session session = jsch.getSession(user, host, port);         session.setPassword(password);         session.setConfig("StrictHostKeyChecking", "no");         session.connect();         channelSftp = (ChannelSftp) session.openChannel("sftp");         channelSftp.connect();     }     public void disconnect() throws Exception {         if (channelSftp != null && channelSftp.isConnected()) {             channelSftp.disconnect();         }     }     public void listFiles() throws Exception {         Vector files = channelSftp.ls(".");         for (ChannelSftp.LsEntry file : files) {             System.out.println(file.getFilename());         }     }     public void uploadFile(String localPath, String remotePath) throws Exception {         File file = new File(localPath);         InputStream inputStream = new FileInputStream(file);         channelSftp.put(inputStream, remotePath);         inputStream.close();     }     public void downloadFile(String remotePath, String localPath) throws Exception {         OutputStream outputStream = new FileOutputStream(localPath);         channelSftp.get(remotePath, outputStream);         outputStream.close();     } }