java ftp上传下载文件最全工具类

配置文件

ftp:
  host: 127.0.0.1
  port: 21
  user: user
  pwd: pwd
  bankPath: /home/
  platform: /home/

先附上完整工具类代码

package cn.chinaunicom.mall.bhrb.utils;

/**
 * @author yinna
 * @version 1.0
 * @date 2021/3/26 16:25
 */

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 org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.net.ftp.FTPReply;

public class FtpUtil {

    /**
     * 上传文件（可供Action/Controller层使用）
     *
     * @param hostname    FTP服务器地址
     * @param port        FTP服务器端口号
     * @param username    FTP登录帐号
     * @param password    FTP登录密码
     * @param pathname    FTP服务器保存目录
     * @param fileName    上传到FTP服务器后的文件名称
     * @param inputStream 输入文件流
     * @return
     */
    public static boolean uploadFile(String hostname, int port, String username, String password, String pathname, String fileName, InputStream inputStream) {
        boolean flag = false;
        FTPClient ftpClient = new FTPClient();
        ftpClient.setControlEncoding("UTF-8");
        try {
            //连接FTP服务器
            ftpClient.connect(hostname, port);
            //登录FTP服务器
            ftpClient.login(username, password);
            //是否成功登录FTP服务器
            int replyCode = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(replyCode)) {
                return false;
            }

            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
            ftpClient.makeDirectory(pathname);
            ftpClient.changeWorkingDirectory(pathname);
            ftpClient.storeFile(fileName, inputStream);
            inputStream.close();
            ftpClient.logout();
            flag = true;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ftpClient.isConnected()) {
                try {
                    ftpClient.disconnect();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return flag;
    }


    /**
     * 删除文件
     *
     * @param hostname FTP服务器地址
     * @param port     FTP服务器端口号
     * @param username FTP登录帐号
     * @param password FTP登录密码
     * @param pathname FTP服务器保存目录
     * @param filename 要删除的文件名称
     * @return
     */
    public static boolean deleteFile(String hostname, int port, String username, String password, String pathname, String filename) {
        boolean flag = false;
        FTPClient ftpClient = new FTPClient();
        try {
            //连接FTP服务器
            ftpClient.connect(hostname, port);
            //登录FTP服务器
            ftpClient.login(username, password);
            //验证FTP服务器是否登录成功
            int replyCode = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(replyCode)) {
                return false;
            }
            //切换FTP目录
            ftpClient.changeWorkingDirectory(pathname);
            ftpClient.dele(filename);
            ftpClient.logout();
            flag = true;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ftpClient.isConnected()) {
                try {
                    ftpClient.logout();
                } catch (IOException e) {

                }
            }
        }
        return flag;
    }

    /**
     * 下载文件
     *
     * @param hostname  FTP服务器地址
     * @param port      FTP服务器端口号
     * @param username  FTP登录帐号
     * @param password  FTP登录密码
     * @param pathname  FTP服务器文件目录
     * @param filename  文件名称
     * @param localpath 下载后的文件路径
     * @return
     */
    public static boolean downloadFile(String hostname, int port, String username, String password, String pathname, String filename, String localpath) {
        boolean flag = false;
        FTPClient ftpClient = new FTPClient();
        try {
            //连接FTP服务器
            ftpClient.connect(hostname, port);
            //登录FTP服务器
            ftpClient.login(username, password);
            //验证FTP服务器是否登录成功
            int replyCode = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(replyCode)) {
                return false;
            }
            //切换FTP目录
            ftpClient.changeWorkingDirectory(pathname);
            FTPFile[] ftpFiles = ftpClient.listFiles();
            for (FTPFile file : ftpFiles) {
                if (filename.equalsIgnoreCase(file.getName())) {
                    File localFile = new File(localpath + "/" + file.getName());
                    OutputStream os = new FileOutputStream(localFile);
                    ftpClient.retrieveFile(file.getName(), os);
                    os.close();
                }
            }
            ftpClient.logout();
            flag = true;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ftpClient.isConnected()) {
                try {
                    ftpClient.logout();
                } catch (IOException e) {

                }
            }
        }
        return flag;
    }

}

当把文件直接返回给前端时

 /**
     * 根据文件路径进行下载操作
     *
     * @param filePath 文 件路径
     * @return 无返回值
     * @throws Exception
     */
    @GetMapping("/downloadFile")
    @ApiOperation("根据文件路径进行下载操作")
    @ApiImplicitParams({
            @ApiImplicitParam(value = "文件路径", name = "filePath", required = true, paramType = "query", dataType = "String"),
    })
    public void downloadFile(String filePath, HttpServletResponse response) throws Exception {

        // 清空response
        response.reset();

        OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
        if (StringUtils.isBlank(filePath)) {
            throw new ServiceErrorException("文件路径有误");
        }
        String[] split = filePath.split("/");
        String fileName = split[split.length - 1];

        FTPClient ftpClient = new FTPClient();
        try {
            //连接FTP服务器
            ftpClient.connect(host, port);
            //登录FTP服务器
            ftpClient.login(user, pwd);
            //验证FTP服务器是否登录成功
            int replyCode = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(replyCode)) {
                throw new Exception();
            }
            //切换FTP目录
            ftpClient.changeWorkingDirectory(bankPath);
            FTPFile[] ftpFiles = ftpClient.listFiles();
            if (ftpFiles.length < 1) {
                throw new ServiceErrorException("文件路径有误");
            }

            if (fileName.equalsIgnoreCase(ftpFiles[0].getName())) {
                ftpClient.retrieveFile(ftpFiles[0].getName(), toClient);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ftpClient.isConnected()) {
                ftpClient.logout();
            }
        }
        // 设置response的Header
        response.addHeader("Content-Disposition", "attachment;filename=" + new String(fileName.getBytes()));
//        response.addHeader("Content-Length", "" + file.length());
        response.setContentType("application/octet-stream");
    }