python开发_xml.etree.ElementTree_XML文件操作_该模块在操作XML数据是存在安全隐患_慎用

xml.etree.ElementTree模块实现了一个简单而有效的用户解析和创建XML数据的API。

在python3.3版本中，该模块进行了一些修改：

xml.etree.cElementTree模块被弃用。

警告：xml.etree.ElementTree模块在解析恶意构造的数据会产生一定的安全隐患。所以使用该模块的时候需要谨慎。

下面来看看该模块是怎样解析和创建XML数据文档的。

首先，我们应该了解一下什么是XML树和元素，XML是一种固有的层次化数据格式，这是一种最自然的格式类表示一棵树。

xml.etree.ElementTree（简写ET）就此而言，ElementTree代表的是整个XML无奈的和元素的一棵树，这棵树有一个唯一的

root根节点。在根节点下面，可以有很多子节点，而每一个子节点又可以有自己的属性或子节点....

我们今天需要解析的XML文件的内容如下：

我把该XML文件保存在：c:\\test\\hongten.xml文件中

 <?xml version="1.0" encoding="UTF-8"?>
 <students>
     <student no="2009081097">
         <name>Hongten</name>
         <gender>M</gender>
         <age>20</age>
         <score subject="math">97</score>
         <score subject="chinese">90</score>
     </student>
     <student no="2009081098">
         <name>DuDu</name>
         <gender>W</gender>
         <age>21</age>
         <score subject="math">87</score>
         <score subject="chinese">96</score>
     </student>
     <student no="2009081099">
         <name>Sum</name>
         <gender>M</gender>
         <age>19</age>
         <score subject="math">64</score>
         <score subject="chinese">98</score>
     </student>
 </students>

在上面的XML文件内容中，我们可以看到此XML文件的根节点为：students
我们可以通过下面的方法获取到根节点：

 import xml.etree.ElementTree as ET
 tree = ET.parse('c:\\test\\hongten.xml')
 root = tree.getroot()
 tag = root.tag          #students

同样的我们也可以获取到根节点的属性：

 attrib = root.attrib     #{}

因为根节点：students是没有属性的，所以为空。

我们要获取根节点：students的子节点名称和属性：

  for child in root:
      print(child.tag, child.attrib)

输出为：

student {'no' : ''}
student {'no' : ''}
student {'no' : ''}

我们同样可以获取属性对应的值：

 for student in root.findall('student'):
     no = student.get('no')
     name = student.find('name').text
     print(no, name)

输出为：

2009081097 Hongten
2009081098 DuDu
2009081099 Sum

当然，我们也可以修改XML文件的内容：

 for age in root.iter('age'):
     new_age = int(age.text) + 1
     age.text = str(new_age)
     age.set('updated', 'yes')
 tree.write('c:\\test\\hongten_update.xml')

修改后的XML文件内容如下：

 <students>
     <student no="2009081097">
         <name>Hongten</name>
         <gender>M</gender>
         <age updated="yes">21</age>
         <score subject="math">97</score>
         <score subject="chinese">90</score>
     </student>
     <student no="2009081098">
         <name>DuDu</name>
         <gender>W</gender>
         <age updated="yes">22</age>
         <score subject="math">87</score>
         <score subject="chinese">96</score>
     </student>
     <student no="2009081099">
         <name>Sum</name>
         <gender>M</gender>
         <age updated="yes">20</age>
         <score subject="math">64</score>
         <score subject="chinese">98</score>
     </student>
 </students>

==================================================================

以下是我对xml.etree.ElementTree模块进行了一些封装

==================================================================

 # -*- coding: utf-8 -*-
 #python xml.etree.ElementTree

 #Author   :   Hongten
 #Mailto   :   hongtenzone@foxmail.com
 #Blog     :   http://www.cnblogs.com/hongten
 #QQ       :   648719819
 #Version  :   1.0
 #Create   :   2013-09-03

 import os
 import xml.etree.ElementTree as ET

 '''
     在python中，解析XML文件有很多中方法
     本文中要使用的方法是：xml.etree.ElementTree
 '''
 #global var
 #show log
 SHOW_LOG = True
 #XML file
 XML_PATH = None

 def get_root(path):
     '''parse the XML file,and get the tree of the XML file
     finally,return the root element of the tree.
     if the XML file dose not exist,then print the information'''
     if os.path.exists(path):
         if SHOW_LOG:
             print('start to parse the file : [{}]'.format(path))
         tree = ET.parse(path)
         return tree.getroot()
     else:
         print('the path [{}] dose not exist!'.format(path))

 def get_element_tag(element):
     '''return the element tag if the element is not None.'''
     if element is not None:
         if SHOW_LOG:
             print('begin to handle the element : [{}]'.format(element))
         return element.tag
     else:
         print('the element is None!')

 def get_element_attrib(element):
     '''return the element attrib if the element is not None.'''
     if element is not None:
         if SHOW_LOG:
             print('begin to handle the element : [{}]'.format(element))
         return element.attrib
     else:
         print('the element is None!')

 def get_element_text(element):
     '''return the text of the element.'''
     if element is not None:
         return element.text
     else:
         print('the element is None!')

 def get_element_children(element):
     '''return the element children if the element is not None.'''
     if element is not None:
         if SHOW_LOG:
             print('begin to handle the element : [{}]'.format(element))
         return [c for c in element]
     else:
         print('the element is None!')

 def get_elements_tag(elements):
     '''return the list of tags of element's tag'''
     if elements is not None:
         tags = []
         for e in elements:
             tags.append(e.tag)
         return tags
     else:
         print('the elements is None!')

 def get_elements_attrib(elements):
     '''return the list of attribs of element's attrib'''
     if elements is not None:
         attribs = []
         for a in elements:
             attribs.append(a.attrib)
         return attribs
     else:
         print('the elements is None!')

 def get_elements_text(elements):
     '''return the dict of element'''
     if elements is not None:
         text = []
         for t in elements:
             text.append(t.text)
         return dict(zip(get_elements_tag(elements), text))
     else:
         print('the elements is None!')

 def init():
     global SHOW_LOG
     SHOW_LOG = True
     global XML_PATH
     XML_PATH = 'c:\\test\\hongten.xml'

 def main():
     init()
     #root
     root = get_root(XML_PATH)
     root_tag = get_element_tag(root)
     print(root_tag)
     root_attrib = get_element_attrib(root)
     print(root_attrib)
     #children
     children = get_element_children(root)
     print(children)
     children_tags = get_elements_tag(children)
     print(children_tags)
     children_attribs = get_elements_attrib(children)
     print(children_attribs)

     print('#' * 50)
     #获取二级元素的每一个子节点的名称和值
     for c in children:
         c_children = get_element_children(c)
         dict_text = get_elements_text(c_children)
         print(dict_text)

 if __name__ == '__main__':
     main()

运行效果：

Python 3.3.2 (v3.3.2:d047928ae3f6, May 16 2013, 00:03:43) [MSC v.1600 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>>
start to parse the file : [c:\test\hongten.xml]
begin to handle the element : [<Element 'students' at 0x0215C5A0>]
students
begin to handle the element : [<Element 'students' at 0x0215C5A0>]
{}
begin to handle the element : [<Element 'students' at 0x0215C5A0>]
[<Element 'student' at 0x0215C600>, <Element 'student' at 0x0215C750>, <Element 'student' at 0x0215C870>]
['student', 'student', 'student']
[{'no': ''}, {'no': ''}, {'no': ''}]
##################################################
begin to handle the element : [<Element 'student' at 0x0215C600>]
{'score': '', 'gender': 'M', 'name': 'Hongten', 'age': ''}
begin to handle the element : [<Element 'student' at 0x0215C750>]
{'score': '', 'gender': 'W', 'name': 'DuDu', 'age': ''}
begin to handle the element : [<Element 'student' at 0x0215C870>]
{'score': '', 'gender': 'M', 'name': 'Sum', 'age': ''}
>>> 

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More reading,and english is important.

I'm Hongten

大哥哥大姐姐，觉得有用打赏点哦！多多少少没关系，一分也是对我的支持和鼓励。谢谢。
Hongten博客排名在100名以内。粉丝过千。
Hongten出品，必是精品。

E | hongtenzone@foxmail.com  B | http://www.cnblogs.com/hongten

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