Java连接FTP进行文件上传下载

╰半橙微兮° 2022-04-13 06:19 385阅读 0赞

### 简易FTP服务器 ###

下载3CDaemon.exe文件，配置用户名、密码和FTP路径

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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。

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