Java连接FTP进行文件上传下载

简易FTP服务器

下载3CDaemon.exe文件，配置用户名、密码和FTP路径

配置完，一个简易的FTP服务器就搭建成功了

 

FTP服务Java操作

直接贴代码

package com.main.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.net.MalformedURLException;

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

/**
 * FTP工具类 基于Apache commons-net-3.6.jar 实现
 * 
 * @author PC
 */
public class FtpUtils {

	// ftp服务器地址
	public String hostname = "192.168.43.235";

	// ftp服务器端口号默认为21
	public Integer port = 21;
	
	// ftp登录账号
	public String username = "admin";
	
	// ftp登录密码fileName
	public String password = "admin123";
	
	public FTPClient ftpClient = null;

	/**
	 * 连接FTP服务器
	 * 默认连接成功
	 */
	public boolean loginFtp() {
		boolean loginResult = true;
		ftpClient = new FTPClient();
		ftpClient.setControlEncoding("UTF-8");
		try {
			System.out.println("连接ftp服务器:" + this.hostname + ":" + this.port);
			
			// 连接登录FTP服务器
			ftpClient.connect(hostname, port);
			loginResult = ftpClient.login(username, password);
			if (!loginResult) {
				System.out.println("connect failed:" + this.hostname + ":" + this.port);
				return loginResult;
			}
			
			System.out.println("connect successfu:" + this.hostname + ":" + this.port);

		} catch (MalformedURLException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return loginResult;
	}

	/**
	 * 上传文件
	 * 
	 * @param pathname ftp服务保存地址
	 * @param fileName 上传到ftp的文件名
	 * @param originfilename 待上传文件的名称（绝对地址） 
	 * @return 成功与否
	 */
	public boolean uploadFile(String pathname, String fileName, String originfilename) {
		boolean flag = false;
		InputStream inputStream = null;
		try {
			loginFtp();
			
			System.out.println("开始上传文件");
			inputStream = new FileInputStream(new File(originfilename));
			
			ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
			mkdir(pathname);
			ftpClient.makeDirectory(pathname);
			ftpClient.changeWorkingDirectory(pathname);
			ftpClient.storeFile(fileName, inputStream);
			inputStream.close();
			ftpClient.logout();
			flag = true;
			System.out.println("上传文件成功");
		} catch (Exception e) {
			System.out.println("上传文件失败");
			e.printStackTrace();
		} finally {
			if (ftpClient.isConnected()) {
				try {
					ftpClient.disconnect();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (null != inputStream) {
				try {
					inputStream.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		return flag;
	}

	/**
	 * 上传文件
	 * 
	 * @param pathname ftp服务保存地址
	 * @param fileName 上传到ftp的文件名
	 * @param inputStream 输入文件流
	 * @return
	 */
	public boolean uploadFile(String pathname, String fileName,
			InputStream inputStream) {
		boolean flag = false;
		try {
			System.out.println("开始上传文件");
			loginFtp();
			ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
			mkdir(pathname);
			ftpClient.makeDirectory(pathname);
			ftpClient.changeWorkingDirectory(pathname);
			ftpClient.storeFile(fileName, inputStream);
			inputStream.close();
			ftpClient.logout();
			flag = true;
			System.out.println("上传文件成功");
		} catch (Exception e) {
			System.out.println("上传文件失败");
			e.printStackTrace();
		} finally {
			if (ftpClient.isConnected()) {
				try {
					ftpClient.disconnect();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (null != inputStream) {
				try {
					inputStream.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		return flag;
	}

	/**
	 * 改变工作路径
	 * @param directory 工作路径
	 * @return
	 */
	public boolean changeWorkingDirectory(String directory) {
		boolean flag = true;
		try {
			flag = ftpClient.changeWorkingDirectory(directory);
			if (flag) {
				System.out.println("进入文件夹" + directory + " 成功！");

			} else {
				System.out.println("进入文件夹" + directory + " 失败！开始创建文件夹");
			}
		} catch (IOException ioe) {
			ioe.printStackTrace();
		}
		return flag;
	}

	/**
	 * 创建目录
	 * 如果FTP服务器已存在该目录，则不创建；否则，创建该目录
	 * @param remoteDir 远程目录
	 * @return 成功与否
	 * @throws IOException
	 */
	public boolean mkdir(String remoteDir) throws IOException {
		boolean success = true;
		String directory = remoteDir + "/";
		
		// 如果远程目录不存在，则递归创建远程服务器目录
		if (!directory.equalsIgnoreCase("/") && !changeWorkingDirectory(new String(directory))) {
			int start = 0;
			int end = 0;
			if (directory.startsWith("/")) {
				start = 1;
			} else {
				start = 0;
			}
			end = directory.indexOf("/", start);
			String path = "";
			String paths = "";
			while (true) {
				String subDirectory = 
						new String(remoteDir.substring(start, end).getBytes("GBK"), "ISO-8859-1");
				path = path + "/" + subDirectory;
				if (!existFile(path)) {
					if (makeDirectory(subDirectory)) {
						changeWorkingDirectory(subDirectory);
					} else {
						System.out.println("创建目录[" + subDirectory + "]失败");
						changeWorkingDirectory(subDirectory);
					}
				} else {
					changeWorkingDirectory(subDirectory);
				}

				paths = paths + "/" + subDirectory;
				start = end + 1;
				end = directory.indexOf("/", start);
				// 检查所有目录是否创建完毕
				if (end <= start) {
					break;
				}
			}
		}
		return success;
	}

	/**
	 * 判断ftp服务器文件是否存在
	 * @param path 
	 * @return
	 * @throws IOException
	 */
	public boolean existFile(String path) throws IOException {
		boolean flag = false;
		FTPFile[] ftpFileArr = ftpClient.listFiles(path);
		if (ftpFileArr.length > 0) {
			flag = true;
		}
		return flag;
	}

	/**
	 * 创建文件目录
	 * @param dir 待创建目录
	 * @return 成功与否
	 */
	public boolean makeDirectory(String dir) {
		boolean flag = true;
		try {
			flag = ftpClient.makeDirectory(dir);
			if (flag) {
				System.out.println("创建文件夹" + dir + " 成功！");

			} else {
				System.out.println("创建文件夹" + dir + " 失败！");
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return flag;
	}

	/**
	 * 下载文件 
	 * @param pathname FTP服务器文件目录 
	 * @param filename 文件名称 
	 * @param localpath 下载后的文件路径 
	 * @return
	 */
	public boolean downloadFile(String pathname, String filename, String localpath) {
		boolean flag = false;
		boolean fileExist = false;
		OutputStream os = null;
		try {
			// 连接FTP服务
			loginFtp();
			
			System.out.println("开始下载文件");
			
			// 默认FTP登录到FTP根目录下，切换目录到待下载文件目录
			ftpClient.changeWorkingDirectory(pathname);
			FTPFile[] ftpFiles = ftpClient.listFiles();
			for (FTPFile file : ftpFiles) {
				
				// 查找待下载文件
				if (filename.equalsIgnoreCase(file.getName())) {
					fileExist = true;
					File localFile = new File(localpath + "/" + file.getName());
					os = new FileOutputStream(localFile);
					
					// 从远程服务将文件写回到本地流
					ftpClient.retrieveFile(file.getName(), os);
					os.close();
				}
			}
			ftpClient.logout();
			
			if (fileExist) {
				flag = true;
				System.out.println("下载文件成功");
			} else {
				System.out.println("下载目录未找到该文件，文件名" + pathname + "/" + filename);
			}

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (ftpClient.isConnected()) {
				try {
					ftpClient.disconnect();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (null != os) {
				try {
					os.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		return flag;
	}

	/**
	 * 删除文件 
	 * @param pathname FTP服务器保存目录 
	 * @param filename 要删除的文件名称 
	 * @return 成功与否
	 */
	public boolean deleteFile(String pathname, String filename) {
		boolean flag = false;
		try {
			
			loginFtp();
			
			System.out.println("开始删除文件");
			
			// 切换FTP目录
			ftpClient.changeWorkingDirectory(pathname);
			ftpClient.dele(filename);
			ftpClient.logout();
			flag = true;
			System.out.println("删除文件成功");
		} catch (Exception e) {
			System.out.println("删除文件失败");
			e.printStackTrace();
		} finally {
			if (ftpClient.isConnected()) {
				try {
					ftpClient.disconnect();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		return flag;
	}

	public static void main(String[] args) {
		FtpUtils ftp = new FtpUtils();
		
//		ftp.uploadFile("upload/data", "03_Eureka01.pptx", "D://03 运行第一个Eureka程序.pptx");
//		ftp.downloadFile("upload/data", "03_Eureka01.pptx", "D://");
		ftp.deleteFile("upload/data", "03_Eureka01.pptx");
	}
}

 

上面的代码是参考其他网友的代码实现，可以实现一些简单的FTP文件上传下载功能。但是总感觉可以做的更好一些，一些异常情况和特殊场景还未考虑到位，先做个记录，后面再优化。