ftp下载完成后卡在ftpClient.completePendingCommand();

在FTP下载完成后,调用ftpClient.completePendingCommand()可能导致程序卡住不继续执行。该方法是一个同步阻塞操作,如果误用,会造成程序假死。正确使用时机是在涉及返回流的操作,如上传和下载后。只有在调用有返回流的方法时,如上传和下载,才需手动调用completePendingCommand(),否则可能导致卡死超时。

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下载完成后,若有 boolean upNewStatus = ftpClient.completePendingCommand();,到此会停住不往下执行,必须重启,否则不会往下执行
   

 * There are a few FTPClient methods that do not complete the
    * entire sequence of FTP commands to complete a transaction.  These
    * commands require some action by the programmer after the reception
    * of a positive intermediate command.  After the programmer's code
    * completes its actions, it must call this method to receive
    * the completion reply from the server and verify the success of the
    * entire transaction.
   public boolean completePendingCommad() throws IOException;
   {
        return FTPReply.isPositiveCompletion(getReply());
   }

方法介绍中未说明,在何种情况下应该使用该方法。但是跟踪代码可以发现
这是一个同步阻塞方法,如果调用错误,会导致程序卡住假死在这里。
卡住代码
 String line = _controlInput_.readLine()

package com.epf.nrt.document.utils; import org.apache.commons.net.ftp.FTP; import org.apache.commons.net.ftp.FTPClient; import org.apache.commons.net.ftp.FTPFile; import org.apache.commons.net.ftp.FTPReply; import org.apache.commons.pool2.impl.GenericObjectPool; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import java.io.*; import java.nio.charset.Charset; //@Slf4j @Component public class ContinueFTP { public FTPClient ftpClient; @Autowired private GenericObjectPool<FTPClient> pool; public ContinueFTP() throws Exception { ftpClient = pool.borrowObject(); // 设置将过程中使用到的命令输出到控制台 // this.ftpClient.addProtocolCommandListener(new // PrintCommandListener(new PrintWriter(System.out))); } /** * 连接到FTP服务器 * * @param hostname 主机名 * @param port 端口 * @param username 用户名 * @param password 密码 * @return 是否连接成功 * @throws IOException */ public boolean connect(String hostname, int port, String username, String password) throws Exception { try { // if(!ftpClient.isConnected()){ ftpClient.connect(hostname, port); // } // ftpClient.setControlEncoding("GBK"); //ftpClient.setConnectTimeout(60*000); //连接超时为60秒 } catch (Exception e) { e.printStackTrace(); throw new Exception("登陆异常,请检查主机端口"); } if (FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) { if (ftpClient.login(username, password)) { //该代码的作用是将文件编码由ISO-889-1转为utf-8,也可以转为其他的,例如GBK ftpClient.setControlEncoding("UTF-8"); ftpClient.setCharset(Charset.forName("UTF-8")); return true; } else throw new Exception("登陆异常,请检查密码账号"); } else throw new Exception("登陆异常"); } /** * 从FTP服务器上下载文件,支持断点续传,上传百分比汇报 * * @param remote 远程文件路径 * @param local 本地文件路径 * @return 上传的状态 * @throws IOException */ public DownloadStatus download(String remote, String local) throws IOException { // 设置被动模式 ftpClient.enterLocalPassiveMode(); // 设置以二进制方式传输 ftpClient.setFileType(FTP.BINARY_FILE_TYPE); DownloadStatus result; // 检查远程文件是否存在 FTPFile[] files = ftpClient.listFiles(new String(remote.getBytes("UTF-8"), "UTF-8")); if (files.length != 1) { // System.out.println("远程文件不存在"); //log.info("远程文件不存在"); return DownloadStatus.Remote_File_Noexist; } long lRemoteSize = files[0].getSize(); File f = new File(local); // 本地存在文件,进行断点下载 if (f.exists()) { long localSize = f.length(); // 判断本地文件大小是否大于远程文件大小 if (localSize >= lRemoteSize) { //log.info("本地文件大于远程文件,下载中止"); return DownloadStatus.Local_Bigger_Remote; } // 进行断点续传,并记录状态 FileOutputStream out = new FileOutputStream(f, true); // 找出本地已经接收了多少 ftpClient.setRestartOffset(localSize); InputStream in = ftpClient.retrieveFileStream(new String(remote.getBytes("UTF-8"), "UTF-8")); try { byte[] bytes = new byte[1024]; // 总的进度 long step = lRemoteSize / 100; long process = localSize / step; int c; while ((c = in.read(bytes)) != -1) { out.write(bytes, 0, c); localSize += c; long nowProcess = localSize / step; if (nowProcess > process) { process = nowProcess; if (process % 10 == 0) { //log.info("下载进度:" + process); } // TODO 更新文件下载进度,值存放在process变量中 } } } catch (Exception e) { } finally { if (in != null) in.close(); if (out != null) out.close(); } // 确认是否全部下载完毕 boolean isDo = ftpClient.completePendingCommand(); if (isDo) { result = DownloadStatus.Download_From_Break_Success; } else { result = DownloadStatus.Download_From_Break_Failed; } } else { OutputStream out = new FileOutputStream(f); InputStream in = ftpClient.retrieveFileStream(new String(remote.getBytes("UTF-8"), "UTF-8")); try { byte[] bytes = new byte[1024]; long step = lRemoteSize / 100; long process = 0; long localSize = 0L; int c; while ((c = in.read(bytes)) != -1) { out.write(bytes, 0, c); localSize += c; long nowProcess = localSize / step; if (nowProcess > process) { process = nowProcess; if (process % 10 == 0) { //log.info("下载进度:" + process); } // TODO 更新文件下载进度,值存放在process变量中 } } } catch (Exception e) { } finally { if (in != null) in.close(); if (out != null) out.close(); } boolean upNewStatus = ftpClient.completePendingCommand(); if (upNewStatus) { result = DownloadStatus.Download_New_Success; } else { result = DownloadStatus.Download_New_Failed; } } return result; } /** * 从FTP服务器上下载文件流,以便下载 * * @param remote 远程文件路径 * @return 上传的状态 * @throws IOException */ public InputStream getFTPFileInputStream(String remote) throws IOException { // 设置被动模式 ftpClient.enterLocalPassiveMode(); // 设置以二进制方式传输 ftpClient.setFileType(FTP.BINARY_FILE_TYPE); // 检查远程文件是否存在 FTPFile[] files = ftpClient.listFiles(new String(remote.getBytes("UTF-8"), "UTF-8")); if (files.length != 1) { // System.out.println("远程文件不存在"); //log.info("远程文件不存在"); return null; } // 找出本地已经接收了多少 InputStream in = ftpClient.retrieveFileStream(new String(remote.getBytes("UTF-8"), "UTF-8")); // 确认是否全部下载完毕 // boolean isDo = ftpClient.completePendingCommand(); // if (isDo) { return in; // } else { // return null; // } } /** * 上传文件到FTP服务器,支持断点续传 * * @param local 本地文件名称,绝对路径 * @param remote 远程文件路径,使用/home/directory1/subdirectory/file.ext * 按照Linux上的路径指定方式,支持多级目录嵌套,支持递归创建不存在的目录结构 * @return 上传结果 * @throws IOException */ public UploadStatus upload(File localFile, String remote) throws IOException { // 设置PassiveMode传输 ftpClient.enterLocalPassiveMode(); // 设置以二进制流的方式传输 ftpClient.setFileType(FTP.BINARY_FILE_TYPE); ftpClient.setControlEncoding("UTF-8"); UploadStatus result; // 对远程目录的处理 String remoteFileName = remote; if (remote.contains("/")) { remoteFileName = remote.substring(remote.lastIndexOf("/") + 1); // 创建服务器远程目录结构,创建失败直接返回 if (CreateDirecroty(remote, ftpClient) == UploadStatus.Create_Directory_Fail) { return UploadStatus.Create_Directory_Fail; } } // 检查远程是否存在文件 FTPFile[] files = ftpClient.listFiles(new String(remoteFileName.getBytes("UTF-8"), "UTF-8")); if (files.length == 1) { long remoteSize = files[0].getSize(); long localSize = localFile.length(); if (remoteSize == localSize) { return UploadStatus.File_Exits; } else if (remoteSize > localSize) { return UploadStatus.Remote_Bigger_Local; } // 尝试移动文件内读取指针,实现断点续传 result = uploadFile(remoteFileName, localFile, ftpClient, remoteSize); // 如果断点续传没有成功,则删除服务器上文件,重新上传 if (result == UploadStatus.Upload_From_Break_Failed) { if (!ftpClient.deleteFile(remoteFileName)) { return UploadStatus.Delete_Remote_Faild; } result = uploadFile(remoteFileName, localFile, ftpClient, 0); } } else { result = uploadFile(remoteFileName, localFile, ftpClient, 0); } return result; } /** * 断开与远程服务器的连接 * * @throws IOException */ public void disconnect() throws IOException { if (ftpClient.isConnected()) { ftpClient.disconnect(); } } /** * 递归创建远程服务器目录 * * @param remote 远程服务器文件绝对路径 * @param ftpClient FTPClient对象 * @return 目录创建是否成功 * @throws IOException */ public UploadStatus CreateDirecroty(String remote, FTPClient ftpClient) throws IOException { UploadStatus status = UploadStatus.Create_Directory_Success; String directory = remote.substring(0, remote.lastIndexOf("/") + 1); if (!directory.equalsIgnoreCase("/") && !ftpClient.changeWorkingDirectory(new String(directory.getBytes("UTF-8"), "UTF-8"))) { // 如果远程目录不存在,则递归创建远程服务器目录 int start = 0; int end = 0; if (directory.startsWith("/")) { start = 1; } else { start = 0; } end = directory.indexOf("/", start); while (true) { String subDirectory = new String(remote.substring(start, end).getBytes("UTF-8"), "UTF-8"); if (!ftpClient.changeWorkingDirectory(subDirectory)) { if (ftpClient.makeDirectory(subDirectory)) { ftpClient.changeWorkingDirectory(subDirectory); } else { System.out.println("创建目录失败"); return UploadStatus.Create_Directory_Fail; } } start = end + 1; end = directory.indexOf("/", start); // 检查所有目录是否创建完毕 if (end <= start) { break; } } } return status; } /** * 上传文件到服务器,新上传和断点续传 * * @param remoteFile 远程文件名,在上传之前已经将服务器工作目录做了改变 * @param localFile 本地文件File句柄,绝对路径 * @param processStep 需要显示的处理进度步进值 * @param ftpClient FTPClient引用 * @return * @throws IOException */ public UploadStatus uploadFile(String remoteFile, File localFile, FTPClient ftpClient, long remoteSize) throws IOException { UploadStatus status; // 显示进度的上传 // long step = localFile.length() / 100; // long process = 0; // long localreadbytes = 0L; RandomAccessFile raf = new RandomAccessFile(localFile, "r"); OutputStream out = ftpClient.appendFileStream(new String(remoteFile.getBytes("UTF-8"), "UTF-8")); // 断点续传 if (remoteSize > 0) { ftpClient.setRestartOffset(remoteSize); // process = remoteSize / step; raf.seek(remoteSize); // localreadbytes = remoteSize; } byte[] bytes = new byte[1024]; int c; while ((c = raf.read(bytes)) != -1) { out.write(bytes, 0, c); // localreadbytes += c; // if (localreadbytes / step != process) { // process = localreadbytes / step; // System.out.println("上传进度:" + process); // TODO 汇报上传状态 // } } out.flush(); raf.close(); out.close(); boolean result = ftpClient.completePendingCommand(); if (remoteSize > 0) { status = result ? UploadStatus.Upload_From_Break_Success : UploadStatus.Upload_From_Break_Failed; } else { status = result ? UploadStatus.Upload_New_File_Success : UploadStatus.Upload_New_File_Failed; } return status; } public enum DownloadStatus { Remote_File_Noexist, // 远程文件不存在 Local_Bigger_Remote, // 本地文件大于远程文件 Download_From_Break_Success, // 断点下载文件成功 Download_From_Break_Failed, // 断点下载文件失败 Download_New_Success, // 全新下载文件成功 Download_New_Failed; // 全新下载文件失败 } public enum UploadStatus { Create_Directory_Fail, // 远程服务器相应目录创建失败 Create_Directory_Success, // 远程服务器闯将目录成功 Upload_New_File_Success, // 上传新文件成功 Upload_New_File_Failed, // 上传新文件失败 File_Exits, // 文件已经存在 Remote_Bigger_Local, // 远程文件大于本地文件 Upload_From_Break_Success, // 断点续传成功 Upload_From_Break_Failed, // 断点续传失败 Delete_Remote_Faild; // 删除远程文件失败 } } 调整下,原代码逻辑尽量不变,只是改造下 连接的创建和释放
最新发布
05-14
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