FTP服务器上传下载

windows下FTP服务器可以使用3CDaemon，下载后点击FTP服务器设置进行相关设置：

使用jar包坐标如下：

<dependency>
            <groupId>commons-net</groupId>
            <artifactId>commons-net</artifactId>
            <version>3.6</version>
        </dependency>           

使用java连接服务器并进行操作，登录FTP后默认在FTP根目录下，如果操作文件需要切换到待操作目录。

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 com.btzh.exception.BusinessException;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
import org.springframework.util.StringUtils;

/**
 * FTP工具类
 *
 * @author faith
 */
public class FtpUtil {
 
    public final static String HOSTNAME = "127.0.0.1";
    public final static Integer PORT = 21;
    public final static String USERNAME = "admin";
    public final static String PASSWORD = "666666";
    public static FTPClient FTP_CLIENT;

    public static void main(String[] args) {
        FtpUtil.uploadFileByPath("/upload/img/", "test.jpg", "D:\\timg.jpg");
        FtpUtil.downloadFile("/upload/img/", "test.jpg", "D:\\ftp");
        FtpUtil.deleteFile("upload/img", "test.jpg");
    }

    /**
     * 上传文件by文件名
     * @param pathName
     * @param fileName
     * @param originFileName
     */
    public static void uploadFileByPath(String pathName, String fileName, String originFileName) {
        InputStream inputStream = null;
        FTP_CLIENT = getFtpClient();

        try {
            FTP_CLIENT.setFileType(FTP.BINARY_FILE_TYPE);

            createIfNotExsit(pathName);
            FTP_CLIENT.storeFile(fileName, inputStream = new FileInputStream(new File(originFileName)));
        } catch (Exception e) {
            throw new RuntimeException("上传文件失败: " + e);
        } finally {
            closeIOResource(FTP_CLIENT, inputStream, null);
        }
    }

    /**
     * 上传文件by流
     * @param pathname
     * @param fileName
     * @param inputStream
     */
    public static void uploadFileByStream(String pathname, String fileName, InputStream inputStream) {
        FTP_CLIENT = getFtpClient();

        try {
            FTP_CLIENT.setFileType(FTP.BINARY_FILE_TYPE);

            createIfNotExsit(pathname);
            FTP_CLIENT.storeFile(fileName, inputStream);
        } catch (Exception e) {
            throw new RuntimeException("上传文件失败");
        } finally {
            closeIOResource(FTP_CLIENT, inputStream, null);
        }
    }
 
    /**
     * 下载文件 
     * @param pathname
     * @param filename
     * @param localPath
     * @return
     */
    public static void downloadFile(String pathname, String filename, String localPath) {
        OutputStream outputStream = null;
        FTP_CLIENT = getFtpClient();

        try {
            FTP_CLIENT.changeWorkingDirectory(pathname);

            FTPFile[] ftpFiles = FTP_CLIENT.listFiles();
            for (FTPFile ftpFile : ftpFiles) {
                if (ftpFile.getName().equalsIgnoreCase(filename)) {
                    FTP_CLIENT.retrieveFile(ftpFile.getName(), outputStream = new FileOutputStream(new File(localPath + "/" + ftpFile.getName())));
                    return;
                }
            }

            throw new BusinessException("未找到文件：" + pathname + "/" + filename);
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            closeIOResource(FTP_CLIENT, null, outputStream);
        }
    }

    /**
     * 删除文件
     * @param pathName
     * @param fileName
     */
    public static void deleteFile(String pathName, String fileName) {
        FTP_CLIENT = getFtpClient();

        try {
            FTP_CLIENT.changeWorkingDirectory(pathName);
            FTP_CLIENT.dele(fileName);
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            closeIOResource(FTP_CLIENT, null, null);
        }
    }

    /**
     * 改变工作目录
     * @param directory
     * @return
     */
    public static boolean changeWorkingDirectory(String directory) {
        try {
            return FTP_CLIENT.changeWorkingDirectory(directory);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 创建目录
     * @param directory
     */
    public static void createIfNotExsit(String directory) {
        if (directory.equalsIgnoreCase("/")) {
            return;
        }

        while (directory.startsWith("/") || directory.endsWith("/")) {
            directory = directory.substring(directory.startsWith("/") ? 1 : 0, directory.endsWith("/") ? directory.length() - 1 : directory.length());
            if (directory.equalsIgnoreCase("/")) {
                return;
            }
        }

        String[] filePaths = StringUtils.delimitedListToStringArray(directory, "/");
        for (String filePath : filePaths) {
            if (!existFilePath(filePath)) {
                makeDirectory(filePath);
            }
            changeWorkingDirectory(filePath);
        }
    }

    /**
     * 判断文件是否存在
     * @param filePath
     * @return
     */
    public static boolean existFilePath(String filePath) {
        try {
            return FTP_CLIENT.listFiles(filePath).length > 0;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 创建文件目录
     * @param directory
     * @return
     */
    public static boolean makeDirectory(String directory) {
        try {
            return FTP_CLIENT.makeDirectory(directory);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 连接FTP服务器
     */
    public static FTPClient getFtpClient() {
        FTP_CLIENT = new FTPClient();
        FTP_CLIENT.setControlEncoding("UTF-8");

        try {
            FTP_CLIENT.connect(HOSTNAME, PORT);

            if (!FTP_CLIENT.login(USERNAME, PASSWORD)) {
                throw new RuntimeException("ftp登录失败");
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        return FTP_CLIENT;
    }

    /**
     * 关闭使用的资源
     * @param ftpClient
     * @param inputStream
     */
    private static void closeIOResource(FTPClient ftpClient, InputStream inputStream, OutputStream outputStream) {
        if (ftpClient.isConnected()) {
            try {
                ftpClient.logout();
                ftpClient.disconnect();
            } catch (IOException e) {
            }
        }
        if (null != inputStream) {
            try {
                inputStream.close();
            } catch (IOException e) {
            }
        }
        if (null != outputStream) {
            try {
                outputStream.close();
            } catch (IOException e) {
            }
        }
    }
}