使用apache的commons-net-3.1.jar實現FTP上傳

commons-net-3.1.jar下載地址

在有些項目中我們需要將文件保存在FTP中，

但是在網上介紹FTP上傳的知識總是感覺很混亂，

現在將網上的一些代碼經過整理與測試，拿出來與大家分享。

有些地方寫的可能不是很好，還望大家見諒。

我覺得在向FTP上傳文件的時候上傳文件並不是最難的，而是如何在FTP上創建文件夾。

package com.ftp.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;

public class FtpDemo {
	/**
	 * 連接FTP
	 * 
	 * @param ip
	 * @param port
	 * @param userName
	 * @param password
	 * @param file
	 * @param remotePathName
	 * @param remoteName
	 */
	private static void upload(String ip, int port, String userName,
			String password, File file, String remotePathName, String remoteName) {
		FTPClient ftpClient = new FTPClient();
		try {
			ftpClient.connect(ip, port);
			ftpClient.login(userName, password);
			ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
			ftpClient.enterLocalPassiveMode();

			// 上傳文件
			upload(ftpClient, file, remotePathName, remoteName);

		} catch (Exception e) {
			System.out.println("fail to upload files : " + e.getMessage());
		} finally {
			if (ftpClient != null && ftpClient.isConnected()) {
				try {
					ftpClient.disconnect();
				} catch (IOException e) {
					System.out.println("ftp fails to disconnect : "
							+ e.getMessage());
				}
			}
		}
	}

	/**
	 * 上傳文件
	 * 
	 * @param ftpClient
	 * @param file
	 * @param remotePathName
	 * @param remoteName
	 */
	private static void upload(FTPClient ftpClient, File file,
			String remotePathName, String remoteName) throws Exception {
		try {
			// 1. 切目錄
			changeDirectory(ftpClient, remotePathName);
			// 2. 傳文件
			uploadFile(ftpClient, file, remotePathName, remoteName);
			// 3. 切回根目錄
			backToRootDirectory(ftpClient);
		} catch (IOException e) {
		}
	}

	/**
	 * 切換目錄
	 * 
	 * @param ftpClient
	 * @param path
	 * @throws IOException
	 */
	private static void changeDirectory(FTPClient ftpClient, String path)
			throws IOException {
		int nextSeperator = path.indexOf("/", 1);
		String currentPath = null;
		if (nextSeperator < 0) {
			nextSeperator = path.length();
			currentPath = path.substring(1, nextSeperator);
			changeDirectory0(ftpClient, currentPath);
			return;
		} else {
			currentPath = path.substring(1, nextSeperator);
			changeDirectory0(ftpClient, currentPath);
			changeDirectory(ftpClient, path.substring(nextSeperator));
		}
	}

	/**
	 * 如果切換的目錄不存在 就創建一個新的目錄
	 * 
	 * @param ftpClient
	 * @param path
	 * @throws IOException
	 */
	private static void changeDirectory0(FTPClient ftpClient, String path)
			throws IOException {
		if (!ftpClient.changeWorkingDirectory(path)) {
			ftpClient.makeDirectory(path);
		}
		ftpClient.changeWorkingDirectory(path);
	}

	/**
	 * 回到根目錄根
	 * 
	 * @param ftpClient
	 * @throws IOException
	 */
	private static void backToRootDirectory(FTPClient ftpClient)
			throws IOException {
		ftpClient.changeWorkingDirectory("/");
	}

	/**
	 * 真正的上傳文件方法
	 * 
	 * @param ftpClient
	 * @param file
	 * @param remotePathName
	 * @param remoteName
	 */
	private static void uploadFile(FTPClient ftpClient, File file,
			String remotePathName, String remoteName) throws Exception {
		String localPathName = file.getAbsolutePath();
		FTPFile[] files = ftpClient.listFiles(remoteName);
		if (files.length == 1) {
			if (!ftpClient.deleteFile(remoteName)) {
				throw new Exception("fail to delete remote file ["
						+ remotePathName + "] before uploading");
			}
		}
		File f = new File(localPathName);
		InputStream is = new FileInputStream(f);
		if (!ftpClient.storeFile(remoteName, is)) {
			is.close();
		}
		is.close();
	}
}