ftp上传和下载

阳光穿透心脏的1/2处 2022-06-10 11:22 375阅读 0赞

在java代码里面使用ftp，可以使用Apache 里面的一个common-net包，具体下载可以去官网下载。  
使用ftp最主要的类还是FTPClient。下面是ftp官方文档的介绍

public class FTPClient
    extends FTP
    implements Configurable
    FTPClient encapsulates all the functionality necessary to store and retrieve files from an FTP server. This class takes care of all low level details of interacting with an FTP server and provides a convenient higher level interface. As with all classes derived from SocketClient, you must first connect to the server with connect before doing anything, and finally disconnect after you're completely finished interacting with the server. Then you need to check the FTP reply code to see if the connection was successful.

还有一个小案例：

FTPClient ftp = new FTPClient();
        FTPClientConfig config = new FTPClientConfig();
        config.setXXX(YYY); // change required options
        // for example config.setServerTimeZoneId("Pacific/Pitcairn")
        ftp.configure(config );
        boolean error = false;
        try {
          int reply;
          String server = "ftp.example.com";
          ftp.connect(server);
          System.out.println("Connected to " + server + ".");
          System.out.print(ftp.getReplyString());
    
          // After connection attempt, you should check the reply code to verify
          // success.
          reply = ftp.getReplyCode();
    
          if(!FTPReply.isPositiveCompletion(reply)) {
            ftp.disconnect();
            System.err.println("FTP server refused connection.");
            System.exit(1);
          }
          ... // transfer files
          ftp.logout();
        } catch(IOException e) {
          error = true;
          e.printStackTrace();
        } finally {
          if(ftp.isConnected()) {
            try {
              ftp.disconnect();
            } catch(IOException ioe) {
              // do nothing
            }
          }
          System.exit(error ? 1 : 0);
        }

大概了解后可以写一个ftp上传和下载的工具类，下面就是代码：

public class FtpUtil { 
    
        /** * Description: 向FTP服务器上传文件 * @param host FTP服务器hostname * @param port FTP服务器端口 * @param username FTP登录账号 * @param password FTP登录密码 * @param basePath FTP服务器基础目录 * @param filePath FTP服务器文件存放路径。例如分日期存放：/2015/01/01。文件的路径为basePath+filePath * @param filename 上传到FTP服务器上的文件名 * @param input 输入流 * @return 成功返回true，否则返回false */  
        public static boolean uploadFile(String host, int port, String username, String password, String basePath,
                String filePath, String filename, InputStream input) {
            boolean result = false;
            FTPClient ftp = new FTPClient();
            try {
                int reply;
                ftp.connect(host, port);// 连接FTP服务器
                // 如果采用默认端口，可以使用ftp.connect(host)的方式直接连接FTP服务器
                ftp.login(username, password);// 登录
                reply = ftp.getReplyCode();
                if (!FTPReply.isPositiveCompletion(reply)) {
                    ftp.disconnect();
                    return result;
                }
                //切换到上传目录
                if (!ftp.changeWorkingDirectory(basePath+filePath)) {
                    //如果目录不存在创建目录
                    String[] dirs = filePath.split("/");
                    String tempPath = basePath;
                    for (String dir : dirs) {
                        if (null == dir || "".equals(dir)) continue;
                        tempPath += "/" + dir;
                        if (!ftp.changeWorkingDirectory(tempPath)) {
                            if (!ftp.makeDirectory(tempPath)) {
                                return result;
                            } else {
                                ftp.changeWorkingDirectory(tempPath);
                            }
                        }
                    }
                }
                //设置上传文件的类型为二进制类型
                ftp.setFileType(FTP.BINARY_FILE_TYPE);
                //上传文件
                if (!ftp.storeFile(filename, input)) {
                    return result;
                }
                input.close();
                ftp.logout();
                result = true;
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (ftp.isConnected()) {
                    try {
                        ftp.disconnect();
                    } catch (IOException ioe) {
                    }
                }
            }
            return result;
        }
    
        /** * Description: 从FTP服务器下载文件 * @param host FTP服务器hostname * @param port FTP服务器端口 * @param username FTP登录账号 * @param password FTP登录密码 * @param remotePath FTP服务器上的相对路径 * @param fileName 要下载的文件名 * @param localPath 下载后保存到本地的路径 * @return */  
        public static boolean downloadFile(String host, int port, String username, String password, String remotePath,
                String fileName, String localPath) {
            boolean result = false;
            FTPClient ftp = new FTPClient();
            try {
                int reply;
                ftp.connect(host, port);
                // 如果采用默认端口，可以使用ftp.connect(host)的方式直接连接FTP服务器
                ftp.login(username, password);// 登录
                reply = ftp.getReplyCode();
                if (!FTPReply.isPositiveCompletion(reply)) {
                    ftp.disconnect();
                    return result;
                }
                ftp.changeWorkingDirectory(remotePath);// 转移到FTP服务器目录
                FTPFile[] fs = ftp.listFiles();
                for (FTPFile ff : fs) {
                    if (ff.getName().equals(fileName)) {
                        File localFile = new File(localPath + "/" + ff.getName());
    
                        OutputStream is = new FileOutputStream(localFile);
                        ftp.retrieveFile(ff.getName(), is);
                        is.close();
                    }
                }
    
                ftp.logout();
                result = true;
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (ftp.isConnected()) {
                    try {
                        ftp.disconnect();
                    } catch (IOException ioe) {
                    }
                }
            }
            return result;
        }
        }