JAVA操作FTP（FTP工具类）

<dependency>
    <groupId>commons-net</groupId>
    <artifactId>commons-net</artifactId>
    <version>3.6</version>
</dependency>

package com.my.ftp.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.StringTokenizer;

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

public class Ftp { 
   

	private String Control_Encoding = "UTF-8";

	private FTPClient client = null;

	private String host = "";
	private int port = 21;
	private String user = "";
	private String password = "";
	private String ftpPath = "/";

	@SuppressWarnings("unused")
	private Ftp() { 
   
	}

	public Ftp(String host, int port, String user, String pwd) { 
   
		this.host = host;
		this.port = port;
		this.user = user;
		this.password = pwd;
	}

	/** * 获取当前FTP所在目录位置 * * @return */
	public String getHome() { 
   
		return this.ftpPath;
	}

	/** * 连接FTP Server * * @throws IOException */
	public static final String ANONYMOUS_USER = "anonymous";

	public void connect() throws Exception { 
   
		if (client == null) { 
   
			client = new FTPClient();
		}
		// 已经连接
		if (client.isConnected()) { 
   
			return;
		}

		// 编码
		client.setControlEncoding(Control_Encoding);

		try { 
   
			// 连接FTP Server
			client.connect(this.host, this.port);
			// 登陆
			if (this.user == null || "".equals(this.user)) { 
   
				// 使用匿名登陆
				client.login(ANONYMOUS_USER, ANONYMOUS_USER);
			} else { 
   
				client.login(this.user, this.password);
			}
			// 设置文件格式
			client.setFileType(FTPClient.BINARY_FILE_TYPE);
			// 获取FTP Server 应答
			int reply = client.getReplyCode();
			if (!FTPReply.isPositiveCompletion(reply)) { 
   
				client.disconnect();
				throw new Exception("connection FTP fail!");
			}

			FTPClientConfig config = new FTPClientConfig(client.getSystemType().split(" ")[0]);
			config.setServerLanguageCode("zh");
			client.configure(config);
			// 使用被动模式设为默认
			client.enterLocalPassiveMode();
			// 二进制文件支持
			client.setFileType(FTP.BINARY_FILE_TYPE);
			// 设置模式
			client.setFileTransferMode(FTP.STREAM_TRANSFER_MODE);

		} catch (IOException e) { 
   
			throw new Exception("connection FTP fail! " + e);
		}
	}

	/** * 断开FTP连接 * * @param ftpClient * @throws IOException */
	public void close() { 
   
		if (client != null && client.isConnected()) { 
   
			try { 
   
				client.logout();
				client.disconnect();
			} catch (IOException e) { 
   
				e.printStackTrace();
			}
		}
	}

	/** * 获取文件列表 * * @return */
	public List<FTPFile> list() { 
   
		List<FTPFile> list = null;
		try { 
   
			FTPFile ff[] = client.listFiles(ftpPath);
			if (ff != null && ff.length > 0) { 
   
				list = new ArrayList<FTPFile>(ff.length);
				Collections.addAll(list, ff);
			} else { 
   
				list = new ArrayList<FTPFile>(0);
			}
		} catch (IOException e) { 
   
			e.printStackTrace();
		}
		return list;
	}

	/** * 切换目录 * * @param path * 需要切换的目录 * @param forcedIncrease * 如果目录不存在，是否增加 */
	public void switchDirectory(String path, boolean forcedIncrease) { 
   
		try { 
   
			if (path != null && !"".equals(path)) { 
   
				boolean ok = client.changeWorkingDirectory(path);
				if (ok) { 
   
					this.ftpPath = path;
				} else if (forcedIncrease) { 
   
					// ftpPath 不存在，手动创建目录
					StringTokenizer token = new StringTokenizer(path, "\\//");
					while (token.hasMoreTokens()) { 
   
						String npath = token.nextToken();
						client.makeDirectory(npath);
						client.changeWorkingDirectory(npath);
						if (ok) { 
   
							this.ftpPath = path;
						}
					}
				}
			}
		} catch (Exception e) { 
   
			e.printStackTrace();
		}
	}

	/** * 创建目录 * * @param path */
	public void createDirectory(String path) { 
   
		try { 
   
			if (path != null && !"".equals(path)) { 
   
				boolean ok = client.changeWorkingDirectory(path);
				if (!ok) { 
   
					// ftpPath 不存在，手动创建目录
					StringTokenizer token = new StringTokenizer(path, "\\//");
					while (token.hasMoreTokens()) { 
   
						String npath = token.nextToken();
						client.makeDirectory(npath);
						client.changeWorkingDirectory(npath);
					}
				}
			}
			client.changeWorkingDirectory(this.ftpPath);
		} catch (Exception e) { 
   
			e.printStackTrace();
		}
	}

	/** * 删除目录，如果目录中存在文件或者文件夹则删除失败 * * @param path * @return */
	public boolean deleteDirectory(String path) { 
   
		boolean flag = false;
		try { 
   
			flag = client.removeDirectory(path);
		} catch (IOException e) { 
   
			e.printStackTrace();
		}
		return flag;
	}

	/** * 删除文件 * * @param path * @return */
	public boolean deleteFile(String path) { 
   
		boolean flag = false;
		try { 
   
			flag = client.deleteFile(path);
		} catch (IOException e) { 
   
			e.printStackTrace();
		}
		return flag;
	}

	/** * 上传文件，上传文件只会传到当前所在目录 * * @param localFile * 本地文件 * @return */
	public boolean upload(File localFile) { 
   
		return this.upload(localFile, "");
	}

	/** * 上传文件，会覆盖FTP上原有文件 * * @param localFile * 本地文件 * @param reName * 重名 * @return */
	public boolean upload(File localFile, String reName) { 
   
		boolean flag = false;
		String targetName = reName;
		// 设置上传后文件名
		if (reName == null || "".equals(reName)) { 
   
			targetName = localFile.getName();
		}
		FileInputStream fis = null;
		try { 
   
			// 开始上传文件
			fis = new FileInputStream(localFile);
			client.setControlEncoding(Control_Encoding);
			client.setFileType(FTPClient.BINARY_FILE_TYPE);
			boolean ok = client.storeFile(targetName, fis);
			if (ok) { 
   
				flag = true;
			}
		} catch (IOException e) { 
   
			e.printStackTrace();
		}
		return flag;
	}

	/** * 下载文件，如果存在会覆盖原文件 * * @param ftpFileName * 文件名称，FTP上的文件名称 * @param savePath * 保存目录，本地保存目录 * @return */
	public boolean download(String ftpFileName, String savePath) { 
   
		boolean flag = false;

		File dir = new File(savePath);

		if (!dir.exists()) { 
   
			dir.mkdirs();
		}

		FileOutputStream fos = null;
		try { 
   
			String saveFile = dir.getAbsolutePath() + File.separator + ftpFileName;
			fos = new FileOutputStream(new File(saveFile));
			boolean ok = client.retrieveFile(ftpFileName, fos);
			if (ok) { 
   
				flag = true;
			}
		} catch (IOException e) { 
   
			e.printStackTrace();
		}
		return flag;
	}

	public static void main(String args[]) { 
   

		// 创建FTP对象
		Ftp ftp = new Ftp("127.0.0.1", 21, "myftp", "myftp@2020");
		try { 
   
			// 连接FTP
			ftp.connect();

			// 移动工作空间、切换目录
			System.out.println("当前位置：" + ftp.getHome());
			ftp.switchDirectory("/test", true);
			System.out.println("当前位置：" + ftp.getHome());

			// 查询目录下的所有文件夹以及文件
			List<FTPFile> list = ftp.list();
			System.out.println("|-- " + ftp.getHome());
			for (FTPFile f : list) { 
   
				System.out.println(" |-- [" + (f.getType() == 0 ? "文件" : "文件夹") + "]" + f.getName());
			}

			// 上传文件
			boolean r1 = ftp.upload(new File("C:\\Users\\joymt\\Documents\\ftp\\测试文件1.txt"), "测试文件2.txt");
			System.out.println("上传文件：" + r1);

			// 下载文件
			boolean r2 = ftp.download("测试文件2.txt", "C:\\Users\\joymt\\Documents\\ftp");
			System.out.println("下载文件：" + r2);

			// 删除文件
			boolean r3 = ftp.deleteFile("/test/测试文件2.txt");
			System.out.println("删除文件：" + r3);

			// 删除目录
			boolean r4 = ftp.deleteDirectory("/test");
			System.out.println("删除目录：" + r4);

		} catch (Exception e) { 
   
			e.printStackTrace();
		}

		ftp.close();
	}

}