0

我编写了一个类，它从 ftp 站点（ftp://ladsweb.nascom.nasa.gov/allData/5/MOD11A1/）下载一个文件，在调用类实例时给定部分文件名。后来我写了一个for循环并将类实例集成到for循环中，这样我就可以下载多个日期范围内的文件。这是一个日期范围，因为文件是根据它们的生成日期命名的。所以每天都有文件。当您运行代码时，系统会要求您输入日期范围。该范围的第一个文件已成功下载，但是当程序停止并打印以下错误时：

Traceback (most recent call last):
      File "ftplib04Simplified.py", line 42, in <module>
        FtpDownloader("ladsweb.nascom.nasa.gov","/allData/5/MOD11A1/",a).findFile(10,11)
      File "ftplib04Simplified.py", line 32, in findFile
        self.ftp.retrbinary('RETR %s' % filename, open(filename,'wb').write)
      File "/usr/lib/python3.3/ftplib.py", line 424, in retrbinary
        with self.transfercmd(cmd, rest) as conn:
      File "/usr/lib/python3.3/ftplib.py", line 386, in transfercmd
        return self.ntransfercmd(cmd, rest)[0]
      File "/usr/lib/python3.3/ftplib.py", line 352, in ntransfercmd
        resp = self.sendcmd(cmd)
      File "/usr/lib/python3.3/ftplib.py", line 259, in sendcmd
        return self.getresp()
      File "/usr/lib/python3.3/ftplib.py", line 233, in getresp
        raise error_perm(resp)
    ftplib.error_perm: 550 No such file.

    shell returned 1

我知道纯类设计会让我感到羞耻，但这是我编写的完整代码： PS 这是用 Python 3 编写的。如果运行代码，当要求输入时，请输入 2001 年之后的日期。

import ftplib
import math
import datetime as dt
import time
class FtpDownloader:
    """Downloads raster tiles given the date, and tile row and column number"""
    def __init__(self,site,directory,raw_date,ftp=None):
        """logs in to ftp"""
        self.site=site
        self.directory=directory
        self.raw_date=raw_date
        self.ftp=ftplib.FTP(site)
        self.ftp.login()
        self.convert_date()
    def convert_date(self):
        """converts YYYY-MM-DD format to year and day of the year"""
        year=self.raw_date.strftime("%Y")
        day=self.raw_date.strftime("%j")
        self.go_to_folder(year,day)
    def go_to_folder(self,year,day):
        """sets the current FTP directory"""
        self.ftp.cwd(self.directory+"%s/%s/" % (year,day))
    def findFile(self,h,v,fileList=[]):
        """checks for the file containing the given h and h and downloads it using retrbinary"""
        hh= "%02d" % h
        vv= "%02d" % v
        tilename = "h%sv%s" % (hh,vv)
        print ("Image tile %s is downloading..." % tilename)
        self.ftp.retrlines('NLST',fileList.append)
        for filename in fileList:
            if tilename in filename:
                self.ftp.retrbinary('RETR %s' % filename, open(filename,'wb').write)
                print ("File downloaded")
                break
        else:
            print (filename, "not found")
        self.ftp.close()
start=dt.datetime.strptime(input("Enter a start date in YYYY-MM-DD format "),"%Y-%m-%d")
end=dt.datetime.strptime(input("Enter an end date in YYYY-MM-DD format "),"%Y-%m-%d")
for i in range((end-start).days + 1):
    a=(start+dt.timedelta(days=i)).date()
    FtpDownloader("ladsweb.nascom.nasa.gov","/allData/5/MOD11A1/",a).findFile(10,11)
4

1 回答 1

-1

这正是您指示计算机执行的操作：break下载第一个文件后立即中断下载循环：

def findFile(self,h,v,fileList=[]):
    """checks for the file containing the given h and h and downloads it using retrbinary"""
    hh= "%02d" % h
    vv= "%02d" % v
    tilename = "h%sv%s" % (hh,vv)
    print ("Image tile %s is downloading..." % tilename)
    self.ftp.retrlines('NLST',fileList.append)
    for filename in fileList:
        if tilename in filename:
            self.ftp.retrbinary('RETR %s' % filename, open(filename,'wb').write)
            print ("File downloaded")
            break
    else:
        print (filename, "not found")
    self.ftp.close()

只需替换上面的breakfor continue，它应该可以工作。- 更好的是，因为你的 for 循环中没有其他语句，所以只需完全删除该行。

于 2013-10-08T14:41:20.033 回答