getPath(ftp,path,pathArray);

 public static void getPath(FTPClient ftp,String path,ArrayList<String> pathArray) throws IOException{
    FTPFile[] files = ftp.listFiles();
    for (FTPFile ftpFile : files) {
      if(ftpFile.getName().equals(".")||ftpFile.getName().equals(".."))continue;
      if(ftpFile.isDirectory()){//如果是目录，则递归调用，查找里面所有文件
        path+="/"+ftpFile.getName();
        pathArray.add(path);
        ftp.changeWorkingDirectory(path);//改变当前路径
        getPath(ftp,path,pathArray);//递归调用
        path=path.substring(0, path.lastIndexOf("/"));//避免对之后的同目录下的路径构造作出干扰，
      }
    }
  }

 public static void download(FTPClient ftp,ArrayList<String> pathArray,String localRootPath) throws IOException{
    for (String string : pathArray) {
      String localPath=localRootPath+string;
      File localFile = new File(localPath);
      if (!localFile.exists()) { 
        localFile.mkdirs(); 
      }
    }
    for (String string : pathArray) {
      String localPath=localRootPath+string;//构造本地路径
      ftp.changeWorkingDirectory(string);
      FTPFile[] file=ftp.listFiles();
      for (FTPFile ftpFile : file) {
        if(ftpFile.getName().equals(".")||ftpFile.getName().equals(".."))continue;
        File localFile = new File(localPath);
        if(!ftpFile.isDirectory()){
          OutputStream is = new FileOutputStream(localFile+"/"+ftpFile.getName());
          ftp.retrieveFile(ftpFile.getName(), is);
          is.close();
        }
      }
    }
  }

 public static void main(String[] args) throws SocketException, IOException {
    FTPClient ftp = new FTPClient();
    ftp.connect("127.0.0.1");
    ftp.login("test","test");
    int reply;
    reply = ftp.getReplyCode();
    if(!FTPReply.isPositiveCompletion(reply)) {
      ftp.disconnect();
      System.err.println("FTP server refused connection.");
      System.exit(1);
    }
    ftp.setBufferSize(1024);
    ftp.setFileType(FTP.BINARY_FILE_TYPE); 
    ftp.enterLocalPassiveMode();
    String path="";
    ArrayList<String> pathArray=new ArrayList<String>();
    getPath(ftp,path,pathArray);
    System.out.println(pathArray);
    download(ftp, pathArray, "c:\\download");
    ftp.logout();
    ftp.disconnect();
  }