java FTP 下载文件

梦里梦外; 2021-12-10 15:33 280阅读 0赞

package com.jcjt.download.utils;
    
    import org.apache.commons.net.ftp.FTPClient;
    import org.apache.commons.net.ftp.FTPFile;
    import org.apache.commons.net.ftp.FTPReply;
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.net.SocketException;
    
    /**
     * 
     * @description FtpUtils
     * @date 2019/7/9
     **/
    public class FtpUtils {
    
        public static FTPClient getFtpClient(String host) throws SocketException, IOException {
            FTPClient ftp = new FTPClient();
            // 连接
            ftp.connect(host);// 连接FTP服务器
            ftp.login("abc", "123456");// 登陆FTP服务器
            ftp.setControlEncoding("UTF-8"); // 中文支持
            ftp.setFileType(FTPClient.BINARY_FILE_TYPE); //二进制
    	ftp.enterLocalPassiveMode();  // 被动模式
            if (!FTPReply.isPositiveCompletion(ftp.getReplyCode())) {
                ftp.disconnect();
                throw new RuntimeException("未连接到FTP，用户名或密码错误。");
            }
            return ftp;
        }
    
        public static String download(String localpath, String serverIp,String path) {
            String result = "";
            FTPClient ftpClient = null;
            OutputStream ios = null;
            File localFile = null;
            Boolean success = false;
            try {
                ftpClient = getFtpClient(serverIp);
            } catch (IOException e) {
                e.printStackTrace();
                throw new RuntimeException("FTP连接发生异常！", e);
            }
            try {
                //切换下载目录 2019/07/10/16/20190710165044_0_1002_1001.wav
                ftpClient.changeWorkingDirectory("2019/07/10/16/");
                FTPFile[] ftpFiles = ftpClient.listFiles("20190710165044_0_1002_1001.wav");
                if(ftpFiles.length>0){
                    localFile = new File(localpath+"/"+ftpFiles[0].getName());
                    //先判断文件是否存在 如果存在就不重复下载
                    if(!localFile.exists()){
                        ios = new FileOutputStream(localFile);
                        success = ftpClient.retrieveFile(ftpFiles[0].getName(),ios);
                        ios.close();
                    }
                }
                ftpClient.logout();
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                try {
                    if(ios != null){
                        ios.close();
                    }
                    close(ftpClient);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return result;
        }
    
    
        /**
         * ftp 连接断开
         *
         * @param client ftp 客户端
         */
        public static void close(FTPClient client) {
            try {
                if (!client.isConnected())
                    client.disconnect();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
    }