利用java如何实现上传ftp文件

public boolean connect(String path, String addr, int port, String username, String password) {    try {      //FTPClient ftp = new FTPHTTPClient(addr, port, username, password);      ftp = new FTPClient();      int reply;      ftp.connect(addr);      System.out.println("连接到：" + addr + ":" + port);      System.out.print(ftp.getReplyString());      reply = ftp.getReplyCode();       if (!FTPReply.isPositiveCompletion(reply)) {        ftp.disconnect();        System.err.println("FTP目标服务器积极拒绝.");        System.exit(1);        return false;      }else{        ftp.login(username, password);        ftp.enterLocalPassiveMode();        ftp.setFileType(FTPClient.BINARY_FILE_TYPE);        ftp.changeWorkingDirectory(path);        System.out.println("已连接：" + addr + ":" + port);        return true;      }    } catch (Exception ex) {      ex.printStackTrace();      System.out.println(ex.getMessage());      return false;    }  }