Python 如何检查两个以上URL的HTTP错误？

问题：我有3个URL-testurl1、testurl2和testurl3。我想先尝试testurl1，如果我得到404错误，然后尝试testurl2，如果得到404错误，然后尝试testurl3。如何做到这一点？到目前为止，我已经尝试了下面的方法，但这只适用于两个url，如何添加对第三个url的支持？

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普通旧for循环的另一个作业：

for url in testurl1, testurl2, testurl3
    req = Request(url)
    try:
        response = urlopen(req)
    except HttpError as err:
        if err.code == 404:
            continue
        raise
    else:
        # do what you want with successful response here (or outside the loop)
        break
else:
    # They ALL errored out with HTTPError code 404.  Handle this?
    raise err

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嗯，也许是这样的

from urllib2 import Request, urlopen
from urllib2 import URLError, HTTPError

def checkfiles():
    req = Request('http://testurl1')
    try:
        response = urlopen(req)
        url1=('http://testurl1')

    except HTTPError, URLError:
        try:
            url1 = ('http://testurl2')
        except HTTPError, URLError:
            url1 = ('http://testurl3')
    print url1
    finalURL='wget '+url1+'/testfile.tgz'

    print finalURL

checkfiles()

---

只需检查响应代码。如果它等于

404

执行您需要的操作。不，urllib为404引发HTTPError，而不是代码为404的响应

from urllib2 import Request, urlopen
from urllib2 import URLError, HTTPError

def checkfiles():
    req = Request('http://testurl1')
    try:
        response = urlopen(req)
        url1=('http://testurl1')

    except HTTPError, URLError:
        try:
            url1 = ('http://testurl2')
        except HTTPError, URLError:
            url1 = ('http://testurl3')
    print url1
    finalURL='wget '+url1+'/testfile.tgz'

    print finalURL

checkfiles()