基于Apache FTP点断续传的文件上传和下载

参考地址：http://www.myexception.cn/program/630532.html

基于Apache FTP实现文件上传下载工具 ，上传文件时需要考虑以下问题（实例是续传功能）：

（1）、 FTP服务器是否存在改目录，如果不存在目录则需要创建目录。

（2）、判断上传文件是否已经存在，如果存在是需要删除后再上传还是续传。

1、上传或下载状态的枚举类：

package com.scengine.wtms.utils.ftp;
 
public enum UploadStatus
{
	File_Exits(0), Create_Directory_Success(1), Create_Directory_Fail(2), Upload_From_Break_Success(3), Upload_From_Break_Faild(4), Download_From_Break_Success(5), Download_From_Break_Faild(6), Upload_New_File_Success(7), Upload_New_File_Failed(8), Delete_Remote_Success(9), Delete_Remote_Faild(10),Remote_Bigger_Local(11),Remote_smaller_locall(12);
 
	private int status;
 
	public int getStatus()
	{
		return status;
	}
 
	public void setStatus(int status)
	{
		this.status = status;
	}
 
	UploadStatus(int status)
	{
		this.status = status;
	}
}

2、工具类代码：

package com.scengine.wtms.utils.ftp;
 
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 java.io.PrintWriter;
import org.apache.commons.net.PrintCommandListener;
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;
 
public class ContinueFTP
{
 
	private FTPClient ftpClient = new FTPClient();
 
	/**
	 * 对象构造 设置将过程中使用到的命令输出到控制台
	 */
	public ContinueFTP()
	{
		this.ftpClient.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));
	}
 
	/**
	 * 
	 * java编程中用于连接到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 IOException
	{
 
		ftpClient.connect(hostname, port);
 
		if (FTPReply.isPositiveCompletion(ftpClient.getReplyCode()))
		{
 
			if (ftpClient.login(username, password))
			{
				return true;
			}
		}
		disconnect();
		return false;
 
	}
 
	/**
	 * 
	 * 从FTP服务器上下载文件
	 * 
	 * @param remote
	 *            远程文件路径
	 * 
	 * @param local
	 *            本地文件路径
	 * 
	 * @return 是否成功
	 * 
	 * @throws IOException
	 */
 
	@SuppressWarnings("resource")
	public boolean download(String remote, String local) throws IOException
	{
 
		ftpClient.enterLocalPassiveMode();
 
		ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
 
		boolean result;
 
		File f = new File(local);
 
		FTPFile[] files = ftpClient.listFiles(remote);
 
		if (files.length != 1)
		{
			System.out.println("远程文件不唯一");
			return false;
		}
 
		long lRemoteSize = files[0].getSize();
 
		if (f.exists())
		{
			OutputStream out = new FileOutputStream(f, true);
			System.out.println("本地文件大小为:" + f.length());
 
			if (f.length() >= lRemoteSize)
			{
 
				System.out.println("本地文件大小大于远程文件大小，下载中止");
 
				return false;
 
			}
 
			ftpClient.setRestartOffset(f.length());
 
			result = ftpClient.retrieveFile(remote, out);
 
			out.close();
 
		} else
		{
 
			OutputStream out = new FileOutputStream(f);
			result = ftpClient.retrieveFile(remote, out);
			out.close();
		}
 
		return result;
 
	}
 
	/**
	 * 
	 * 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
	 */
 
	@SuppressWarnings("resource")
	public UploadStatus upload(String local, 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);
 
		UploadStatus result;
 
		// 对远程目录的处理
 
		String remoteFileName = remote;
 
		if (remote.contains("/"))
		{
 
			remoteFileName = remote.substring(remote.lastIndexOf("/") + 1);
 
			String directory = remote.substring(0, remote.lastIndexOf("/") + 1);
 
			if (!directory.equalsIgnoreCase("/") && !ftpClient.changeWorkingDirectory(directory))
			{
 
				// 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 = remote.substring(start, end);
 
					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;
 
					}
 
				}
 
			}
 
		}
 
		// 检查远程是否存在文件
 
		FTPFile[] files = ftpClient.listFiles(remoteFileName);
 
		if (files.length == 1)
		{
 
			long remoteSize = files[0].getSize();
 
			File f = new File(local);
 
			long localSize = f.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
 
			InputStream is = new FileInputStream(f);
 
			if (is.skip(remoteSize) == remoteSize)
			{
 
				ftpClient.setRestartOffset(remoteSize);
 
				if (ftpClient.storeFile(remote, is))
				{
 
					return UploadStatus.Upload_From_Break_Success;
 
				}
 
			}
 
			// 如果断点续传没有成功，则删除服务器上文件，重新上传
 
			if (!ftpClient.deleteFile(remoteFileName))
			{
 
				return UploadStatus.Delete_Remote_Faild;
 
			}
 
			is = new FileInputStream(f);
 
			if (ftpClient.storeFile(remote, is))
			{
 
				result = UploadStatus.Upload_New_File_Success;
 
			} else
			{
 
				result = UploadStatus.Upload_New_File_Failed;
 
			}
 
			is.close();
 
		} else
		{
 
			InputStream is = new FileInputStream(local);
 
			if (ftpClient.storeFile(remoteFileName, is))
			{
 
				result = UploadStatus.Upload_New_File_Success;
 
			} else
			{
 
				result = UploadStatus.Upload_New_File_Failed;
 
			}
 
			is.close();
		}
 
		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();
		}
 
	}
 
	public static void main(String[] args)
	{
		ContinueFTP myFtp = new ContinueFTP();
		try
		{
 
			myFtp.connect("192.168.1.200", 21, "duser", "HTPDuserXP32");
 
			System.out.println(myFtp.upload("C:\\Users\\Administrator\\Desktop\\swing.drawer.jar", "/jars/swing.drawer.jar"));
 
			myFtp.disconnect();
 
		} catch (IOException e)
		{
 
			System.out.println("连接FTP出错：" + e.getMessage());
 
		}
 
	}
 
}