首先我们引入commons-net依赖，这是个基于Socket的ftp依赖，API在
http://commons.apache.org/proper/commons-net/apidocs/index.html

 <dependency>
			<groupId>commons-net</groupId>
			<artifactId>commons-net</artifactId>
			<version>3.5</version>
</dependency>

登录方式为

//验证登录
        try {
    
            FTPClient ftp = new FTPClient();
            ftp.connect(ip, port);
            System.out.println(ftp.login(name, pwd));
            ftp.setFileType(FTP.BINARY_FILE_TYPE);
            ftp.setCharset(Charset.forName("UTF-8"));
            ftp.setControlEncoding("UTF-8");

        } catch (IOException e) {
    
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

乱码原因是字符编码问题，在ftpcilent处定义下就好

ftp.setFileType(FTP.BINARY_FILE_TYPE);
ftp.setCharset(Charset.forName(“UTF-8”));
ftp.setControlEncoding(“UTF-8”);
获取文件列表方式：

FTPClient f = new FTPClient();
f.connect(server);
f.login(username, password);
FTPFile[] files = f.listFiles(directory);

FTPClient f = new FTPClient();
f.connect(server);
f.login(username,password);
FTPListParseEngine engine =
        f.initiateListParsing("com.whatever.YourOwnParser", directory);
// FTPListParseEngine engine = f.initiateListParsing(directory);
while(engine.hasNext()){
    
    FTPFile[] files = engine.getNext(25);  // "page size" you want
    //do whatever you want with these files, display them, etc.
    //expensive FTPFile objects not created until needed.
}

上传：

public void putFile(File file) {
    
        try {
    
            OutputStream os = ftp.storeFileStream(file.getName());
            FileInputStream fis = new FileInputStream(file);

            byte[] b = new byte[1024];
            int len = 0;
            while ((len = fis.read(b)) != -1) {
    
                os.write(b, 0, len);
            }
        } catch (IOException e) {
    
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
}


public void putFiles(File srcFile) {
    
        try {
    
            if (!srcFile.exists()) {
    
                srcFile.mkdirs();
            }
            for (File file : srcFile.listFiles()) {
    
                if (file.isDirectory()) {
    
                    putFiles(file);
                } else {
    
                    putFile(file);
                }
            }
        } catch (Exception e) {
    
            e.printStackTrace();
        }
}

下载：

public void getFile(String fileName, File file) {
    
        try {
    
            //将ftp的file路径下的"fileName"文件下载到本地目录文件夹下面，并重命名为"fileName"
            ftp.retrieveFile(fileName, new FileOutputStream(new File(file.getPath() + "\\" + fileName)));
        } catch (IOException e) {
    
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

public void getFiles() {
    
        List<String> fileNameList = getFilesName();
        try {
    
            ReadConfig readConfig = new ReadConfig();
            DateUtil dateUtil = new DateUtil();
            File toFile = new File(readConfig.getTempPath() + "\\" + dateUtil.getDay() + "12");
            if (!toFile.exists()) {
    
                toFile.mkdirs();
            }
            for (int i = 0; i < fileNameList.size(); i++) {
    
                getFile(fileNameList.get(i), toFile);
                System.out.println(fileNameList.get(i));
            }
        } catch (Exception e) {
    
            e.printStackTrace();
        }
    }

测试代码：

//    public static void main(String args[]) {
    
//        FTPUtil ftpUtil = new FTPUtil("172.18.66.209",18200,"admin","1234-123");
//        ftpUtil.getFilesName();
//        ftpUtil.getFiles();
//        File file = new File("D:\\thundersource\\2020051112");
//        ftpUtil.putFiles(file);
//        ftpUtil.putFile(file);
//        //ftpUtil.putFile();
//        ftpUtil.getFile();
//    }

需要注意的是，当使用org.apache.commons.net.ftp.FTPClient通过协议SSH2进行SFTP连接时会报Could not parse response code.Server Reply: SSH-2.0-OpenSSH_5.3，原因是它不支持这种方式的连接(使用FTPSClient的SSL也是不行的)。，我们需要使用com.jcraft.jsch.JSch提供的SSH解决方法，
详情请看https://blog.csdn.net/oLengYueHun/article/details/106098501