目录

• 一、引入依赖
• 二、工具类
• 三、测试

一、引入依赖

 //ftp相关
  <!-- https://mvnrepository.com/artifact/commons-net/commons-net -->
<dependency>
    <groupId>commons-net</groupId>
    <artifactId>commons-net</artifactId>
    <version>3.8.0</version>
</dependency>

二、工具类

package com.iscas.biz.util;

import com.iscas.biz.domain.FtpFile;
import org.apache.commons.net.ftp.*;
import org.springframework.util.CollectionUtils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class FtpUtil {

    private FTPClient client = null;

    private FtpUtil() {
    }

    public FtpUtil(String host, int port, String user, String pwd) {
        connect(host, port, user, pwd);
    }

    /**
     * 连接FTP
     */
    public void connect(String host, int port, String user, String pwd) {
        FTPClient client = new FTPClient();
        try {
            // 连接
            client.connect(host, port);
            // 登陆
            if (user == null || "".equals(user)) {
                client.login("anonymous", "anonymous");
            } else {
                client.login(user, pwd);
            }
            // 二进制文件支持
            client.setFileType(FTPClient.BINARY_FILE_TYPE);
            // 获取FTP应答
            int reply = client.getReplyCode();
            if (!FTPReply.isPositiveCompletion(reply)) {
                client.disconnect();
                return;
            }
            FTPClientConfig config = new FTPClientConfig(client.getSystemType().split(" ")[0]);
            client.configure(config);
            client.setBufferSize(1024);
            client.enterLocalPassiveMode();
            client.setControlEncoding("utf-8");
            this.client = client;
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 断开FTP连接
     */
    public void close() {
        if (client != null && client.isConnected()) {
            try {
                client.logout();
                client.disconnect();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 切换目录
     *
     * @param path           需要切换的目录
     * @param forcedIncrease 如果目录不存在，是否增加
     */
    public boolean switchDirectory(String path, boolean forcedIncrease) {
        try {
            if (path != null && !"".equals(path)) {
                boolean success = client.changeWorkingDirectory(path);
                if (!success && forcedIncrease) {
                    String[] paths;
                    if (path.contains("/")) {
                        paths = path.split("/");
                    } else if (path.contains("\\\\")) {
                        paths = path.split("\\\\");
                    } else {
                        paths = new String[1];
                        paths[0] = path;
                    }
                    //创建目录
                    success = Arrays.stream(paths).allMatch(dir -> {
                        try {
                            client.makeDirectory(dir);
                            return client.changeWorkingDirectory(dir);
                        } catch (IOException e) {
                            return false;
                        }
                    });
                }
                return success;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

    /**
     * 删除目录，如果目录中存在文件或者文件夹则删除失败
     */
    public boolean deleteDirectory(String path) {
        boolean success = false;
        try {
            success = client.removeDirectory(path);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return success;
    }

    /**
     * 删除文件
     */
    public boolean deleteFile(String path) {
        boolean flag = false;
        try {
            flag = client.deleteFile(path);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return flag;
    }

    /**
     * 上传文件
     *
     * @param localFile 本地文件
     */
    public boolean upload(File localFile) {
        return this.upload(localFile, "");
    }

    /**
     * 上传文件
     *
     * @param localFile 本地文件
     * @param reName    重命名
     */
    public boolean upload(File localFile, String reName) {
        boolean success = false;
        String targetName = reName;
        // 设置文件名
        if (reName == null || "".equals(reName)) {
            targetName = localFile.getName();
        }
        FileInputStream fis = null;
        try {
            // 上传文件
            fis = new FileInputStream(localFile);
            success = client.storeFile(targetName, fis);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return success;
    }

    /**
     * 下载文件
     *
     * @param ftpFileName 文件名称
     * @param savePath    本地保存目录
     */
    public boolean download(String ftpFileName, String savePath) {
        boolean success = false;
        File dir = new File(savePath);
        if (!dir.exists()) {
            dir.mkdirs();
        }
        FileOutputStream fos;
        try {
            String saveFile = dir.getAbsolutePath() + File.separator + ftpFileName;
            fos = new FileOutputStream(saveFile);
            success = client.retrieveFile(ftpFileName, fos);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return success;
    }

    /**
     * 获取文件列表
     */
    public List<FTPFile> list(String dir) {
        List<FTPFile> list = null;
        try {
            FTPFile ff[] = client.listFiles(dir);
            if (ff != null && ff.length > 0) {
                list = new ArrayList<>(ff.length);
                Collections.addAll(list, ff);
            } else {
                list = new ArrayList<>(0);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return list;
    }

    /**
     * @param firstLevelFiles 子文件
     * @param parentFile      父目录
     * @param ftp
     */
    private static void recursionFiles(List<FTPFile> firstLevelFiles, FtpFile parentFile, FtpUtil ftp) {
        if (CollectionUtils.isEmpty(firstLevelFiles)) {
            return;
        }
        firstLevelFiles.stream().forEach(f -> {
            //当前子文件的处理
            FtpFile file = new FtpFile().setFileType(f.getType()).setFileName(f.getName()).setFilePath(getRemotePath(parentFile.getFilePath(), f.getName()));

            List<FtpFile> children = parentFile.getChildren();
            if (CollectionUtils.isEmpty(children)) {
                children = new ArrayList<>();
                parentFile.setChildren(children);
            }
            children.add(file);
            //下一级子文件的处理
            if (f.isDirectory()) {
                String remotePath = file.getFilePath();
                //切换到下一层子目录后遍历
                ftp.switchDirectory(remotePath, false);
                List<FTPFile> secondLevelFiles = ftp.list(remotePath);
                //递归
                recursionFiles(secondLevelFiles, file, ftp);
            }
        });
    }

    private static String getRemotePath(String parentPath, String name) {
        StringBuilder builder = new StringBuilder(parentPath);
        //File.separator
        if (!parentPath.endsWith("/")) {
            builder.append("/");
        }
        builder.append(name);
        return builder.toString();
    }
}

@Data
@Accessors(chain = true)
public class FtpFile {
    /**
     * 文件名
     */
    private String fileName;
    /**
     * 文件名
     */
    private String filePath;
    /**
     * 文件类型：
     * 0为文件，1为文件夹
     */
    private int fileType;
    /**
     * 子文件列表
     */
    private List<FtpFile> children;
}

三、测试

  public static void main(String args[]) {

        // 创建FTP
        FtpUtil ftp = new FtpUtil("172.16.10.153", 21, "iscas", "password123");
        try {
            // 切换目录
            ftp.switchDirectory("/home/iscas/test", true);

            // 上传文件
            boolean upload = ftp.upload(new File("C:\\Users\\x\\Desktop\\quick-frame-samples.sql"), "test.sql");
            System.out.println("上传文件：" + upload);

            // 下载文件
            boolean download = ftp.download("test.sql", "C:\\Users\\x\\Desktop\\ftp");
            System.out.println("下载文件：" + download);

            // 查询目录下的所有文件夹以及文件
            System.out.println("递归获取文件开始");
            List<FTPFile> firstLevelFiles = ftp.list("/home/iscas/test");
            FtpFile parentFile = new FtpFile().setFileType(1).setFilePath("/home/iscas/test");
            recursionFiles(firstLevelFiles, parentFile, ftp);
            System.out.println("递归获取文件结束");

            // 删除文件
            boolean deleteFile = ftp.deleteFile("/home/iscas/test/test.sql");
            System.out.println("删除文件：" + deleteFile);

            // 删除目录
            boolean deleteDirectory = ftp.deleteDirectory("/home/iscas/test");
            System.out.println("删除目录：" + deleteDirectory);

        } catch (Exception e) {
            e.printStackTrace();
        }

        ftp.close();
    }