前言

可以先参考前面一篇文章 retrieveFileStream 之后需要调用 completePendingCommand 否则业务代码会存在问题 retrieveFileStream 之后需要调用 completePendingCommand 否则业务代码会存在问题

这里的问题主要是来自于某 qq 交流群的网友

呵呵当然这里测试用例代码的问题也是非常多, 我们这里只关注于造成业务异常的相关部分

测试用例

/**
 * @author Jerry.X.He <970655147@qq.com>
 * @version 1.0
 * @date 2022-09-16 15:22
 */
public class Test20MultiThreadDownloadFile implements Runnable {

    public static void main(String[] args) {
        for (int i = 0; i < 6; i++) {
            new Thread(new Test20MultiThreadDownloadFile()).start();
        }
    }

    /* (non-Javadoc)
     * @see java.lang.Runnable#run()
     */
    public void run() {
        while (true) {
            try {
                syncFile();

            } catch (Exception e) {
                System.err.println(ExceptionUtils.getFullStackTrace(e));
            } finally {
                try {
                    Thread.sleep(1000 * 60 * 1);
                } catch (InterruptedException e) {
                    System.err.println(ExceptionUtils.getFullStackTrace(e));
                }
            }

        }

    }

    public void syncFile() {
        FTPClient ftpClient = new FTPClient();
        try {
            ftpClient.connect("localhost", 21);
            if (FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) {
                if (ftpClient.login("root", "root")) {
                    System.out.println("FTP连接成功");
                }
            }

            ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
            ftpClient.enterLocalPassiveMode();
            ftpClient.setFileTransferMode(FTP.BINARY_FILE_TYPE);

            ftpClient.changeWorkingDirectory("/");
            FTPFile[] files = ftpClient.listFiles();

            for (FTPFile ftpFile : files) {
                boolean isPending = false;
                try {
                    //if(StringUtils.equals(DateUtil.formatDate(new Date(), "yyyyMMdd"), ftpFile.getName().substring(28,36))){
                    System.out.println(Thread.currentThread().getName() + "|" + ftpFile.getName() + "开始同步");
                    InputStream input = ftpClient.retrieveFileStream(ftpFile.getName());
//                    isPending = (input != null);
                    //File localFile = new File(ComUtils.getAttachFilePathPrefix()+SysConts.GROUPBILL_ATTA_PATH+ftpFile.getName());
                    File localFile = new File("/Users/jerry/Tmp/Test20MultiThreadDownloadFile/" + ftpFile.getName());
                    localFile.getParentFile().mkdirs();
                    if (!localFile.exists()) {
                        localFile.createNewFile();
                    }
                    if (localFile.length() > 10) {
                        System.out.println(Thread.currentThread().getName() + "|文件已同步，跳过" + ftpFile.getName());
                        continue;
                    }
                    if (!localFile.canWrite()) {
                        System.out.println(Thread.currentThread().getName() + "|文件不能操作，跳过" + ftpFile.getName());
                        continue;
                    }

                    FileOutputStream out = new FileOutputStream(localFile);
                    byte[] buffer = new byte[1024];
                    int read;
                    while ((read = input.read(buffer, 0, buffer.length)) != -1) {
                        out.write(buffer, 0, read);
                    }
                    out.flush();
                    out.close();
                    input.close();
                    isPending = true;
                    System.out.println(Thread.currentThread().getName() + "|文件同步完成，" + ftpFile.getName());
                    //}
                } catch (Exception e) {
                    System.err.println(ExceptionUtils.getFullStackTrace(e));
                } finally {
                    if (isPending) {
                        ftpClient.completePendingCommand();
                        System.out.println(Thread.currentThread().getName() + "发起结束命令");
                    }
                }
            }

        } catch (Exception e) {
            System.err.println(ExceptionUtils.getFullStackTrace(e));
        } finally {
            try {
                if (ftpClient.isConnected()) {
                    ftpClient.disconnect();
                    System.out.println("FTP退出成功");
                }
            } catch (IOException e) {
                System.err.println(ExceptionUtils.getFullStackTrace(e));
            }
        }
    }

}