基于ftp4j的FTP客户端工具

ftp4j是一个FTP客户端Java类库，实现了FTP客户端应具有的大部分功能。可以将ftp4j嵌到你的Java应用中，来传输文件（包括上传和下载），浏览远程FTP服务器上的目录和文件，创建、删除、重命，移动远程目录和文件。ftp4j提供多种方式连接到远程FTP服务器包括：通过TCP/IP直接连接，通过FTP代理、HTTP代理、SOCKS4/4a代理和SOCKS5代理连接，通过SSL安全连接。

ftp4j该项目主页:
http://www.sauronsoftware.it/projects/ftp4j/
http://www.sauronsoftware.it/projects/ftp4j/manual.php

ftp4j这是一个基本类库，用起来有些不爽，首先是受检查异常太多太多，这是合理的，把异常留给使用者灵活处理，其次是提供的客户单API太基础，还不够强悍。下面是我针对实际中最常用的功能所作的一个工具类。

在对待异常的方式上，将检查异常全转换为运行时异常，并对一些潜在操作的错误进行检查，提供了原API中没有的一些功能，批量下载、任务侦听器、检查FTP上文件或目录是否存在以及类型。
 
下面是实现代码：
package lavasoft.common.ftp;

import it.sauronsoftware.ftp4j.FTPClient;
import it.sauronsoftware.ftp4j.FTPFile;
import lavasoft.common.PathToolkit;

import java.io.File;
import java.util.List;

/**
* TTP客户端工具
*
* @author leizhimin 2009-11-30 10:20:17
*/
public final class FTPToolkit {

         private FTPToolkit() {
        }

         /**
         * 创建FTP连接
         *
         * @param host         主机名或IP
         * @param port         ftp端口
         * @param username ftp用户名
         * @param password ftp密码
         * @return 一个客户端
         */
         public static FTPClient makeFtpConnection(String host, int port, String username, String password) {
                FTPClient client = new FTPClient();
                 try {
                        client.connect(host, port);
                        client.login(username, password);
                } catch (Exception e) {
                         throw new FTPRuntimeException(e);
                }
                 return client;
        }

         /**
         * FTP下载文件到本地一个文件夹,如果本地文件夹不存在，则创建必要的目录结构
         *
         * @param client                    FTP客户端
         * @param remoteFileName    FTP文件
         * @param localFolderPath 存的本地目录
         */
         public static void download(FTPClient client, String remoteFileName, String localFolderPath) {
                 int x = isExist(client, remoteFileName);
                MyFtpListener listener = MyFtpListener.instance(FTPOptType.UP);
                File localFolder = new File(localFolderPath);
                 if (localFolder.isFile()) {
                         throw new FTPRuntimeException( "所要的下载保存的地方是一个文件，无法保存！");
                } else {
                         if (!localFolder.exists())
                                localFolder.mkdirs();
                }
                 if (x == FTPFile.TYPE_FILE) {
                        String localfilepath = PathToolkit.formatPath4File(localFolderPath + File.separator + new File(remoteFileName).getName());
                         try {
                                 if (listener != null)
                                        client.download(remoteFileName, new File(localfilepath), listener);
                                 else
                                        client.download(remoteFileName, new File(localfilepath));
                        } catch (Exception e) {
                                 throw new FTPRuntimeException(e);
                        }
                } else {
                         throw new FTPRuntimeException( "所要下载的文件" + remoteFileName + "不存在！");
                }
        }

         /**
         * FTP上传本地文件到FTP的一个目录下
         *
         * @param client                     FTP客户端
         * @param localfile                本地文件
         * @param remoteFolderPath FTP上传目录
         */
         public static void upload(FTPClient client, File localfile, String remoteFolderPath) {
                remoteFolderPath = PathToolkit.formatPath4FTP(remoteFolderPath);
                MyFtpListener listener = MyFtpListener.instance(FTPOptType.UP);
                 try {
                        client.changeDirectory(remoteFolderPath);
                         if (!localfile.exists()) throw new FTPRuntimeException( "所要上传的FTP文件" + localfile.getPath() + "不存在！");
                         if (!localfile.isFile()) throw new FTPRuntimeException( "所要上传的FTP文件" + localfile.getPath() + "是一个文件夹！");
                         if (listener != null)
                                client.upload(localfile, listener);
                         else
                                client.upload(localfile);
                        client.changeDirectory( "/");
                } catch (Exception e) {
                         throw new FTPRuntimeException(e);
                }
        }

         /**
         * FTP上传本地文件到FTP的一个目录下
         *
         * @param client                     FTP客户端
         * @param localfilepath        本地文件路径
         * @param remoteFolderPath FTP上传目录
         */
         public static void upload(FTPClient client, String localfilepath, String remoteFolderPath) {
                File localfile = new File(localfilepath);
                upload(client, localfile, remoteFolderPath);
        }

         /**
         * 批量上传本地文件到FTP指定目录上
         *
         * @param client                     FTP客户端
         * @param localFilePaths     本地文件路径列表
         * @param remoteFolderPath FTP上传目录
         */
         public static void uploadListPath(FTPClient client, List localFilePaths, String remoteFolderPath) {
                remoteFolderPath = PathToolkit.formatPath4FTP(remoteFolderPath);
                 try {
                        client.changeDirectory(remoteFolderPath);
                        MyFtpListener listener = MyFtpListener.instance(FTPOptType.UP);
                         for (String path : localFilePaths) {
                                File file = new File(path);
                                 if (!file.exists()) throw new FTPRuntimeException( "所要上传的FTP文件" + path + "不存在！");
                                 if (!file.isFile()) throw new FTPRuntimeException( "所要上传的FTP文件" + path + "是一个文件夹！");
                                 if (listener != null)
                                        client.upload(file, listener);
                                 else
                                        client.upload(file);
                        }
                        client.changeDirectory( "/");
                } catch (Exception e) {
                         throw new FTPRuntimeException(e);
                }
        }

         /**
         * 批量上传本地文件到FTP指定目录上
         *
         * @param client                     FTP客户端
         * @param localFiles             本地文件列表
         * @param remoteFolderPath FTP上传目录
         */
         public static void uploadListFile(FTPClient client, List localFiles, String remoteFolderPath) {
                 try {
                        client.changeDirectory(remoteFolderPath);
                        remoteFolderPath = PathToolkit.formatPath4FTP(remoteFolderPath);
                        MyFtpListener listener = MyFtpListener.instance(FTPOptType.UP);
                         for (File file : localFiles) {
                                 if (!file.exists()) throw new FTPRuntimeException( "所要上传的FTP文件" + file.getPath() + "不存在！");
                                 if (!file.isFile()) throw new FTPRuntimeException( "所要上传的FTP文件" + file.getPath() + "是一个文件夹！");
                                 if (listener != null)
                                        client.upload(file, listener);
                                 else
                                        client.upload(file);
                        }
                        client.changeDirectory( "/");
                } catch (Exception e) {
                         throw new FTPRuntimeException(e);
                }
        }


         /**
         * 判断一个FTP路径是否存在，如果存在返回类型(FTPFile.TYPE_DIRECTORY=1、FTPFile.TYPE_FILE=0、FTPFile.TYPE_LINK=2)
         * 如果文件不存在，则返回一个-1
         *
         * @param client         FTP客户端
         * @param remotePath FTP文件或文件夹路径
         * @return 存在时候返回类型值(文件0，文件夹1，连接2)，不存在则返回-1
         */
         public static int isExist(FTPClient client, String remotePath) {
                remotePath = PathToolkit.formatPath4FTP(remotePath);
                 int x = -1;
                FTPFile[] list = null;
                 try {
                        list = client.list(remotePath);
                } catch (Exception e) {
                         return -1;
                }
                 if (list.length > 1) return FTPFile.TYPE_DIRECTORY;
                 else if (list.length == 1) {
                        FTPFile f = list[0];
                         if (f.getType() == FTPFile.TYPE_DIRECTORY) return FTPFile.TYPE_DIRECTORY;
                         //假设推理判断
                        String _path = remotePath + "/" + f.getName();
                         try {
                                 int y = client.list(_path).length;
                                 if (y == 1) return FTPFile.TYPE_DIRECTORY;
                                 else return FTPFile.TYPE_FILE;
                        } catch (Exception e) {
                                 return FTPFile.TYPE_FILE;
                        }
                } else {
                         try {
                                client.changeDirectory(remotePath);
                                 return FTPFile.TYPE_DIRECTORY;
                        } catch (Exception e) {
                                 return -1;
                        }
                }
        }

         /**
         * 关闭FTP连接，关闭时候像服务器发送一条关闭命令
         *
         * @param client FTP客户端
         * @return 关闭成功，或者链接已断开，或者链接为null时候返回true，通过两次关闭都失败时候返回false
         */

         public static boolean closeConnection(FTPClient client) {
                 if (client == null) return true;
                 if (client.isConnected()) {
                         try {
                                client.disconnect( true);
                                 return true;
                        } catch (Exception e) {
                                 try {
                                        client.disconnect( false);
                                } catch (Exception e1) {
                                        e1.printStackTrace();
                                         return false;
                                }
                        }
                }
                 return true;
        }
}
 
package lavasoft.common;

import java.io.File;

/**
* 路径处理工具，操作系统自适应
*
* @author leizhimin 2009-11-30 16:01:34
*/
public final class PathToolkit {
         private PathToolkit() {
        }

         /**
         * 格式化文件路径，将其中不规范的分隔转换为标准的分隔符,并且去掉末尾的文件路径分隔符。
         * 本方法操作系统自适应
         *
         * @param path 文件路径
         * @return 格式化后的文件路径
         */
         public static String formatPath4File(String path) {
                String reg0 = "\\\\+";
                String reg = "\\\\+|/+";
                String temp = path.trim().replaceAll(reg0, "/");
                temp = temp.replaceAll(reg, "/");
                 if (temp.length() > 1 && temp.endsWith( "/")) {
                        temp = temp.substring(0, temp.length() - 1);
                }
                temp = temp.replace('/', File.separatorChar);
                 return temp;
        }

         /**
         * 格式化文件路径，将其中不规范的分隔转换为标准的分隔符
         * 并且去掉末尾的"/"符号(适用于FTP远程文件路径或者Web资源的相对路径)。
         *
         * @param path 文件路径
         * @return 格式化后的文件路径
         */
         public static String formatPath4FTP(String path) {
                String reg0 = "\\\\+";
                String reg = "\\\\+|/+";
                String temp = path.trim().replaceAll(reg0, "/");
                temp = temp.replaceAll(reg, "/");
                 if (temp.length() > 1 && temp.endsWith( "/")) {
                        temp = temp.substring(0, temp.length() - 1);
                }
                 return temp;
        }

         /**
         * 获取FTP路径的父路径，但不对路径有效性做检查
         *
         * @param path FTP路径
         * @return 父路径，如果没有父路径，则返回null
         */
         public static String genParentPath4FTP(String path) {
                String pp = new File(path).getParent();
                 if (pp == null) return null;
                 else return formatPath4FTP(pp);
        }
}
 
package lavasoft.common.ftp;

/**
* FTP操作类型
*
* @author leizhimin 2009-11-30 11:16:59
*/
public enum FTPOptType {
        UP( "上传"),
        DOWN( "下载"),
        LIST( "浏览"),
        DELFILE( "删除文件"),
        DELFOD( "删除文件夹"),
        RENAME( "上传");

         private String optname;

        FTPOptType(String optname) {
                 this.optname = optname;
        }

         public String getOptname() {
                 return optname;
        }
}
 
package lavasoft.common.ftp;

import it.sauronsoftware.ftp4j.FTPDataTransferListener;

/**
* FTP监听器,做了简单实现，可以使用commons logger替换System.out.println
*
* @author leizhimin 2009-11-30 11:05:33
*/
public class MyFtpListener implements FTPDataTransferListener {
         private FTPOptType optType;

         public static MyFtpListener instance(FTPOptType optType) {
                 return new MyFtpListener(optType);
        }

         private MyFtpListener(FTPOptType optType) {
                 this.optType = optType;
        }

         public void started() {
                System.out.println(optType.getOptname() + "：FTP启动喽。。。。。。");
        }

         public void transferred( int length) {
                System.out.println(optType.getOptname() + "：FTP传输喽。。。。。。");

        }

         public void completed() {
                System.out.println(optType.getOptname() + "：FTP完成喽。。。。。。");
        }

         public void aborted() {
                System.out.println(optType.getOptname() + "：FTP中止喽。。。。。。");
        }

         public void failed() {
                System.out.println(optType.getOptname() + "：FTP挂掉喽。。。。。。");
        }
}
 
package lavasoft.common.ftp;

/**
* FTP异常
*
* @author leizhimin 2009-11-30 10:28:03
*/
public class FTPRuntimeException extends RuntimeException {
         public FTPRuntimeException() {
                 super();
        }

         public FTPRuntimeException(String message) {
                 super(message);
        }

         public FTPRuntimeException(String message, Throwable cause) {
                 super(message, cause);
        }

         public FTPRuntimeException(Throwable cause) {
                 super(cause);
        }
}
 
package lavasoft;

import it.sauronsoftware.ftp4j.FTPClient;
import lavasoft.common.ftp.FTPToolkit;

/**
* 简单测试下
*
* @author leizhimin 2009-11-30 12:25:42
*/
public class Test {
         public static void main(String args[]) throws Exception {
                String ftpip = "192.168.104.113";
                 int ftpport = 21;
                String ftpuser = "vcomkp.ftpadmin";
                String ftppswd = "ftp";

                FTPClient client = FTPToolkit.makeFtpConnection(ftpip, ftpport, ftpuser, ftppswd);
                FTPToolkit.upload(client, "C:\\Dynamicclrr4.zip", "/aaa/bbb/ccc");
                FTPToolkit.download(client, "/Dynamicclrr4.zip", "D:\\");
                FTPToolkit.closeConnection(client);
        }
}
 
上传：FTP启动喽。。。。。。
上传：FTP传输喽。。。。。。
上传：FTP传输喽。。。。。。
上传：FTP完成喽。。。。。。
上传：FTP启动喽。。。。。。
上传：FTP传输喽。。。。。。
上传：FTP传输喽。。。。。。
上传：FTP完成喽。。。。。。

Process finished with exit code 0
 
本程序在RedHat AS 5上使用vsftpd测试通过，一般来说windows下测试通过的ftp工具，一般在Linux下通不过，因为Windows没有太多权限控制。而Linux控制非常严格，常常因为没有权限而导致操作失败，这时候，要对Linux的FTP用户给读写的权限才能正确执行以上代码。

另外说明一点，在判断ftp服务器上一个文件是否存在的isExist方法，具有一定一个局限性，体现在两方面：一是对特定组件版本的依赖性，不同版本list等方法实现不同，对错误路径的处理也不同。二是，不同的ftp服务器对发送list命令反馈的结果不尽相同。
 
这也是为什么很多ftp组件工具不去实现isExist的方法。对使用本方法测试有异常不符合事实的情况下，需要根据特定的环境测试重新实现isExist方法即可。
 
这里我给出了一个测试：
我用的vsftp目录结构如下
/aaa
/aaa/bbb/ccc
/aaa/bbb/ccc/Dynamicclrr4.zip
 
调用方法测试：
                System.out.println(FTPToolkit.isExist(client, "/aaa/bbb/ccc"));                                     //目录
                System.out.println(FTPToolkit.isExist(client, "/aaa/bbb/ccc/Dynamicclrr4.zip")); //文件
                System.out.println(FTPToolkit.isExist(client, "/aaa/bbb/ccc/xxxxxx.zip"));             //不存在的文件
                System.out.println(FTPToolkit.isExist(client, "/aaa/bbb/pppppdd"));                             //不存在的目录
 
1
0
-1
-1

Process finished with exit code 0
 
可见，打印的结果与实际情况相符。