java ftp详解_Java操作FTP工具类（实例详解）

Java可以通过FTP工具类来操作FTP，以下是一个示例：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.SocketException;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;

public class FTPUtil {
    private static final String FTP_ADDRESS = "ftp服务器地址";
    private static final int FTP_PORT = 21;
    private static final String FTP_USERNAME = "ftp用户名";
    private static final String FTP_PASSWORD = "ftp密码";

    // 连接到FTP服务器
    public static FTPClient connectFTP() throws SocketException, IOException {
        FTPClient ftpClient = new FTPClient();
        ftpClient.connect(FTP_ADDRESS, FTP_PORT);
        ftpClient.login(FTP_USERNAME, FTP_PASSWORD);
        ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
        ftpClient.enterLocalPassiveMode();
        if (!FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) {
            ftpClient.disconnect();
            throw new IOException("连接FTP服务器失败");
        }
        return ftpClient;
    }

    // 上传文件到FTP服务器
    public static void uploadFile(String remotePath, String fileName, InputStream input) throws IOException {
        FTPClient ftpClient = null;
        try {
            ftpClient = connectFTP();
            ftpClient.changeWorkingDirectory(remotePath); // 切换到上传目录
            ftpClient.storeFile(fileName, input);
        } finally {
            if (ftpClient != null) {
                ftpClient.logout();
                ftpClient.disconnect();
            }
        }
    }

    // 从FTP服务器下载文件
    public static void downloadFile(String remotePath, String fileName, OutputStream output) throws IOException {
        FTPClient ftpClient = null;
        try {
            ftpClient = connectFTP();
            ftpClient.changeWorkingDirectory(remotePath); // 切换到下载目录
            ftpClient.retrieveFile(fileName, output);
        } finally {
            if (ftpClient != null) {
                ftpClient.logout();
                ftpClient.disconnect();
            }
        }
    }

    // 删除FTP服务器上的文件
    public static boolean deleteFile(String remotePath, String fileName) throws IOException {
        FTPClient ftpClient = null;
        try {
            ftpClient = connectFTP();
            ftpClient.changeWorkingDirectory(remotePath); // 切换到删除目录
            return ftpClient.deleteFile(fileName);
        } finally {
            if (ftpClient != null) {
                ftpClient.logout();
                ftpClient.disconnect();
            }
        }
    }
}

使用方式：

上传文件：

File file = new File("本地文件路径");
InputStream input = new FileInputStream(file);
FTPUtil.uploadFile("上传目录", "上传的文件名", input);

下载文件：

OutputStream output = new FileOutputStream(new File("本地文件路径"));
FTPUtil.downloadFile("下载目录", "下载的文件名", output);

删除文件：

FTPUtil.deleteFile("删除目录", "删除的文件名");