[java]读取/下载 ftp服务器文件工具类

最近小编遇到这样一个需求：

客户数据存储在ftp服务器上，需要将数据从ftp上下载下来并导入到数据库中，并与数据库中现有的数据进行对比，筛选出有差异的数据。

积累了如下（读取/下载 ftp服务器文件）工具类，希望能帮助到有需要的童鞋：

方式一：使用FTPClient

·用到的jar包：

<dependency>
     <groupId>commons-net</groupId>
     <artifactId>commons-net</artifactId>
     <version>3.4</version>
     <classifier>ftp</classifier>
</dependency>

·FTPUtil工具类：

public class FTPUtils {
    private FTPClient ftpClient = null;
    private String server;
    private int port;
    private String userName;
    private String userPassword;


    public FTPUtils(String server, int port, String userName,
                   String userPassword) {
        this.server = server;
        this.port = port;
        this.userName = userName;
        this.userPassword = userPassword;
    }

    /**
     * 链接到服务器
     *
     * @return
     * @throws Exception
     */
    public boolean open() {
        if (ftpClient != null && ftpClient.isConnected()) {
            return true;
        }
        try {
            ftpClient = new FTPClient();
            // 连接
            ftpClient.connect(this.server, this.port);
            ftpClient.login(this.userName, this.userPassword);
            // 检测连接是否成功
            int reply = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(reply)) {
                this.close();
                System.err.println("FTP server refused connection.");
                System.exit(1);
            }
            System.out.println("open FTP success:" + this.server+";port:"+this.port + ";name:"
                    + this.userName + ";pwd:" + this.userPassword);
            ftpClient.setFileType(ftpClient.BINARY_FILE_TYPE);
            // or ascii
            return true;
        } catch (Exception ex) {
            // 关闭
            this.close();
            ex.printStackTrace();
            return false;
        }

    }
/**
     * 获取目录下所有的文件名称
     *
     * @param filePath
     * @return
     * @throws IOException
     */

    public String[] getFileList(String filePath) throws IOException {
        FTPFile[] list = ftpClient.listFiles();
        String[] fileNameList=new String[list.length];
        if(list.length>0){
            for (int i=0;i<list.length;i++){
                fileNameList[i]=list[i].getName();
            }
        }
        return fileNameList;

    }
public String readFile(String fileName) throws ParseException {
        InputStream ins = null;
        StringBuilder builder = null;
        try {
            // 从服务器上读取指定的文件
            ins = ftpClient.retrieveFileStream(fileName);
            System.out.println(ins);
            BufferedReader reader = new BufferedReader(new InputStreamReader(ins));
            String line;
            builder = new StringBuilder(150);
            while ((line = reader.readLine()) != null) {
                //                System.out.println(line);
                builder.append(line);
            }
            reader.close();
            if (ins != null) {
                ins.close();
            }
            ftpClient.getReply();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return builder.toString();
    }
 /**
     * 关闭链接
     */
    public void close() {
        try {
            if (ftpClient != null && ftpClient.isConnected())
                ftpClient.disconnect();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("Close Server Success :"+this.server+";port:"+this.port);
    }

方式二：使用ChannelSftp

·用到的jar包

<dependency>
    <groupId>com.jcraft</groupId>
    <artifactId>jsch</artifactId>
    <version>0.1.51</version>
</dependency>
<!-- jsch 所依赖的jar包  -->
<dependency>
    <groupId>com.jcraft</groupId>
    <artifactId>jzlib</artifactId>
    <version>1.0.7</version>
</dependency>

·FtpJSchUtil工具类

private static ChannelSftp sftp = null;
    //账号
    private static String user = "***";
    //主机ip
    private static String host =  "***";;
    //密码
    private static String password = "***";;
    //端口
    private static int port = 0000;
    //上传地址
    private static String directory = "/";
    //下载目录
    private static String saveFile = "E:/ftpdata";
    
    public static FtpJSch getConnect(){
        FtpJSch ftp = new FtpJSch();
        try {
            JSch jsch = new JSch();
            //获取sshSession  账号-ip-端口
            Session sshSession =jsch.getSession(user, host,port);
            //添加密码
            sshSession.setPassword(password);
            Properties sshConfig = new Properties();
            //严格主机密钥检查
            sshConfig.put("StrictHostKeyChecking", "no");
            sshSession.setConfig(sshConfig);
            //开启sshSession链接
            sshSession.connect();
            //获取sftp通道
            Channel channel = sshSession.openChannel("sftp");
            //开启
            channel.connect();
            sftp = (ChannelSftp) channel;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return ftp;
    }

    /**
     *
     * @param uploadFile 上传文件的路径
     * @return 服务器上文件名
     */
    public String upload(String uploadFile) {
        File file = null;
        String fileName = null;
        try {
            sftp.cd(directory);
            file = new File(uploadFile);
            //获取随机文件名
            fileName  = UUID.randomUUID().toString() + file.getName().substring(file.getName().length()-5);
            //文件名是 随机数加文件名的后5位
            sftp.put(new FileInputStream(file), fileName);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return file == null ? null : fileName;
    }

    /**
     * 下载文件
     *
//     * @param directory
//     *            下载目录
//     * @param downloadFile
//     *            下载的文件名
//     * @param saveFile
//     *            存在本地的路径
//     * @param sftp
     */
    public static void download(String downloadFileName) {
        try {
            sftp.cd(directory);

            File file = new File(saveFile+"/"+downloadFileName);

            sftp.get(downloadFileName, new FileOutputStream(file));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 删除文件
     *
     * @param deleteFile
     *            要删除的文件名字
//     * @param sftp
     */
    public void delete(String deleteFile) {
        try {
            sftp.cd(directory);
            sftp.rm(deleteFile);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 列出目录下的文件
     *
     * @param directory
     *            要列出的目录
//     * @param sftp
     * @return
     * @throws SftpException
     */
    public static Vector listFiles(String directory)
            throws SftpException {
        System.out.println(sftp.ls(directory));
        return sftp.ls(directory);
    }
}