如何使用python刪除xml中的specifc標簽

Question

我必須在apache-tomcat web.xml文件中刪除一些特定標簽

web.xml中

    <?xml version="1.0" encoding="ISO-8859-1"?>



<web-app xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                      http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0">

  <!-- ======================== Introduction ============================== -->
  <!-- This document defines default values for *all* web applications      -->
  <!-- loaded into this instance of Tomcat.  As each application is         -->
  <!-- deployed, this file is processed, followed by the                    -->
  <!-- "/WEB-INF/web.xml" deployment descriptor from your own               -->
  <!-- applications.                                                        -->
  <!--                                                                      -->
  <!-- WARNING:  Do not configure application-specific resources here!      -->
  <!-- They should go in the "/WEB-INF/web.xml" file in your application.   -->

     <servlet>
        <servlet-name>default</servlet-name>
        <servlet-class>org.apache.catalina.servlets.DefaultServlet</servlet-class>
        <init-param>
            <param-name>debug</param-name>
            <param-value>0</param-value>
        </init-param>
        <init-param>
            <param-name>listings</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
   <servlet>
        <servlet-name>jsp</servlet-name>
        <servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
        <init-param>
            <param-name>fork</param-name>
            <param-value>false</param-value>
        </init-param>
        <init-param>
            <param-name>xpoweredBy</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>3</load-on-startup>
    </servlet>

    <servlet>
        <servlet-name>cgi</servlet-name>
        <servlet-class>org.apache.catalina.servlets.CGIServlet</servlet-class>
        <init-param>
          <param-name>debug</param-name>
          <param-value>0</param-value>
        </init-param>
        <init-param>
          <param-name>cgiPathPrefix</param-name>
          <param-value>WEB-INF/cgi</param-value>
        </init-param>
         <load-on-startup>5</load-on-startup>
    </servlet>
</<web-app>

如果servlet-name == cgi我需要刪除整個servlet標簽。 我的代碼如下：

    from xml.etree.ElementTree import ElementTree
    tree = ElementTree()
    tree.parse('web.xml')
    servlets = tree.findall('servlet')
    print "servlets : ",servlets
    for servlet in servlets:
      servlet_names = foo.findall('servlet-name')
      for servlet_name  in servlet_names:
            if servlet_name == "cgi" :
                    print "servlet_name :", servlet_name
                    servlet.remove(servlet-name)

我將o / p作為servlet：[]而不是所有servlet，並且無法進入for循環。 誰能幫我 ？。

我沒有任何異常

#!/usr/bin/python
from xml.etree.ElementTree import ElementTree
tree = ElementTree()
tree.parse('web.xml')
root = tree.getroot()
ns = '{http://java.sun.com/xml/ns/javaee}'
servlets = root.findall(ns + 'servlet')
print "servlets : ",servlets
for servlet in servlets:
  servlet_names = servlet.findall(ns + 'servlet-name')
  for servlet_name  in servlet_names:
        if servlet_name.text == "cgi" :
                print "servlet_name :", servlet_name.text
                print "removed the cgi serverlet", root.remove(servlet)

=====輸出=============== Servlet：[http://java.sun.com/xml/ns/javaee}位於7f84e09b35a8的servlet，http：// java .sun.com / xml / ns / javaee} servlet在7f84e09b3878>，http：//java.sun.com/xml/ns/javaee} servlet在7f84e09b3bd8>] servlet_name：cgi刪除了cgi serverlet無

====我已經使用pdb跟蹤器找出了\\ n表示的element（servlet）值。

> /apps/manu/python/manunamespace.py(10)<module>()
-> servlet_name=servlet.find('{http://java.sun.com/xml/ns/javaee}servlet-name')
(Pdb) servlet_name
<Element {http://java.sun.com/xml/ns/javaee}servlet-name at 882878>
(Pdb) servlet_name.text
'jsp'
(Pdb) n
> /apps/manu/python/manunamespace.py(11)<module>()
-> print "servlet_name:", servlet_name.text
(Pdb) servlet_name.text
'cgi'
(Pdb) servlet.text
'\n        '
(Pdb) n
servlet_name: cgi
> /apps/manu/python/manunamespace.py(12)<module>()
-> if servlet_name.text == "cgi":
(Pdb) n
> /apps/manu/python/manunamespace.py(13)<module>()
-> print "remove the element"
(Pdb) n
remove the element
> /apps/manu/python/manunamespace.py(14)<module>()
-> print "remove : ",root.remove(servlet)
(Pdb) servlet
<Element {http://java.sun.com/xml/ns/javaee}servlet at 882d88>
(Pdb) servlet.text
'\n 

   '

Answer 1

這是失敗的：

servlets = tree.findall('servlet')

因為您的文檔中沒有servlet元素。 根元素指定：

xmlns="http://java.sun.com/xml/ns/javaee"

這意味着，除非另有說明，否則所有元素都在此XML名稱空間中。 所以你要：

>>> tree.findall('{http://java.sun.com/xml/ns/javaee}servlet')
[<Element {http://java.sun.com/xml/ns/javaee}servlet at 0x7f280ec681b8>,
<Element {http://java.sun.com/xml/ns/javaee}servlet at 0x7f280ec68200>, 
<Element {http://java.sun.com/xml/ns/javaee}servlet at 0x7f280ec682d8>]
>>> 

Answer 2

您找不到要搜索的標簽，因為它們位於默認名稱空間（ http://java.sun.com/xml/ns/javaee ）中。

另外，如果要測試元素的內容，則需要使用其text屬性，而不是與元素本身進行比較。 如果匹配，你需要刪除servlet從根，而不是-tag servlet-name來自標簽servlet 。

嘗試這個：

from xml.etree.ElementTree import ElementTree
tree = ElementTree()
tree.parse('web.xml')
root = tree.getroot()
nsmap = {'jee': 'http://java.sun.com/xml/ns/javaee'}
servlets = root.findall('jee:servlet', nsmap)
print "servlets : ",servlets
for servlet in servlets:
  servlet_names = servlet.findall('jee:servlet-name', nsmap)
  for servlet_name  in servlet_names:
        if servlet_name.text == "cgi" :
                print "servlet_name :", servlet_name.text
                root.remove(servlet)

或者更有效地使用受支持的xpath語法 ：

from xml.etree.ElementTree import ElementTree
tree = ElementTree()
tree.parse('web.xml')
root = tree.getroot()
nsmap = {'jee': 'http://java.sun.com/xml/ns/javaee'}
for servlet in root.findall("./jee:servlet[jee:servlet-name='cgi']", nsmap):
    root.remove(servlet)

編輯：對於較舊的python版本（使用python2.5測試）：

from xml.etree.ElementTree import ElementTree
tree = ElementTree()
tree.parse('web.xml')
root = tree.getroot()
ns = '{http://java.sun.com/xml/ns/javaee}'
servlets = root.findall(ns + 'servlet')
print "servlets : ",servlets
for servlet in servlets:
  servlet_names = servlet.findall(ns + 'servlet-name')
  for servlet_name  in servlet_names:
        if servlet_name.text == "cgi" :
                print "servlet_name :", servlet_name.text
                root.remove(servlet)