ElementTree操作实例

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使用ElementTree，先将文件读入，解析成树，之后，根据路径，可以定位到树的每个节点，再对节点进行修改，最后直接将其输出.

#!/usr/bin/python  # -*- coding=utf-8 -*-  # author : wklken@yeah.net  # date: 2012-05-25  # version: 0.1from xml.etree.ElementTree import ElementTree,Elementdef read_xml(in_path):      '''        读取并解析xml文件         in_path: xml路径         return: ElementTree    '''      tree = ElementTree()      tree.parse(in_path)      return treedef write_xml(tree, out_path):      '''        将xml文件写出         tree: xml树         out_path: 写出路径    '''      tree.write(out_path, encoding="utf-8",xml_declaration=True)def if_match(node, kv_map):      '''        判断某个节点是否包含所有传入参数属性         node: 节点         kv_map: 属性及属性值组成的map    '''      for key in kv_map:          if node.get(key) != kv_map.get(key):              return False      return True#---------------search -----def find_nodes(tree, path):      '''        查找某个路径匹配的所有节点         tree: xml树         path: 节点路径    '''      return tree.findall(path)def get_node_by_keyvalue(nodelist, kv_map):      '''        根据属性及属性值定位符合的节点，返回节点         nodelist: 节点列表         kv_map: 匹配属性及属性值map    '''      result_nodes = []      for node in nodelist:          if if_match(node, kv_map):              result_nodes.append(node)      return result_nodes#---------------change -----def change_node_properties(nodelist, kv_map, is_delete=False):      '''        修改/增加 /删除 节点的属性及属性值         nodelist: 节点列表         kv_map:属性及属性值map    '''      for node in nodelist:          for key in kv_map:              if is_delete:                   if key in node.attrib:                      del node.attrib[key]              else:                  node.set(key, kv_map.get(key))def change_node_text(nodelist, text, is_add=False, is_delete=False):      '''        改变/增加/删除一个节点的文本         nodelist:节点列表         text : 更新后的文本    '''      for node in nodelist:          if is_add:              node.text += text          elif is_delete:              node.text = ""          else:              node.text = textdef create_node(tag, property_map, content):      '''        新造一个节点         tag:节点标签         property_map:属性及属性值map         content: 节点闭合标签里的文本内容         return 新节点    '''      element = Element(tag, property_map)      element.text = content      return elementdef add_child_node(nodelist, element):      '''        给一个节点添加子节点         nodelist: 节点列表         element: 子节点    '''      for node in nodelist:          node.append(element)def del_node_by_tagkeyvalue(nodelist, tag, kv_map):      '''        同过属性及属性值定位一个节点，并删除之         nodelist: 父节点列表         tag:子节点标签         kv_map: 属性及属性值列表    '''      for parent_node in nodelist:          children = parent_node.getchildren()          for child in children:              if child.tag == tag and if_match(child, kv_map):                  parent_node.remove(child)if __name__ == "__main__":    #1. 读取xml文件      tree = read_xml("./test.xml")    #2. 属性修改      #A. 找到父节点      nodes = find_nodes(tree, "processers/processer")    #B. 通过属性准确定位子节点      result_nodes = get_node_by_keyvalue(nodes, {"name":"BProcesser"})    #C. 修改节点属性      change_node_properties(result_nodes, {"age": "1"})    #D. 删除节点属性      change_node_properties(result_nodes, {"value":""}, True)    #3. 节点修改      #A.新建节点      a = create_node("person", {"age":"15","money":"200000"}, "this is the firest content")    #B.插入到父节点之下      add_child_node(result_nodes, a)    #4. 删除节点      #定位父节点      del_parent_nodes = find_nodes(tree, "processers/services/service")    #准确定位子节点并删除之      target_del_node = del_node_by_tagkeyvalue(del_parent_nodes, "chain", {"sequency" : "chain1"})    #5. 修改节点文本      #定位节点      text_nodes = get_node_by_keyvalue(find_nodes(tree, "processers/services/service/chain"), {"sequency":"chain3"})      change_node_text(text_nodes, "new text")    #6. 输出到结果文件      write_xml(tree, "./out.xml")

操作对象（原始xml文件）：

<?xml version="1.0" encoding="UTF-8"?>  <framework>      <processers>          <processer name="AProcesser" file="lib64/A.so"              path="/tmp">          </processer>          <processer name="BProcesser" file="lib64/B.so" value="fordelete">          </processer>          <processer name="BProcesser" file="lib64/B.so2222222"/>        <services>              <service name="search" prefix="/bin/search?"                  output_formatter="OutPutFormatter:service_inc">                <chain sequency="chain1"/>                  <chain sequency="chain2"></chain>              </service>              <service name="update" prefix="/bin/update?">                  <chain sequency="chain3" value="fordelete"/>              </service>          </services>      </processers>  </framework>

执行程序之后，得到的结果文件：

<?xml version='1.0' encoding='utf-8'?>  <framework>      <processers>          <processer file="lib64/A.so" name="AProcesser" path="/tmp">          </processer>          <processer age="1" file="lib64/B.so" name="BProcesser">              <person age="15" money="200000">this is the firest content</person>          </processer>          <processer age="1" file="lib64/B.so2222222" name="BProcesser">              <person age="15" money="200000">this is the firest content</person>          </processer>        <services>              <service name="search" output_formatter="OutPutFormatter:service_inc"                  prefix="/bin/search?">                <chain sequency="chain2" />              </service>              <service name="update" prefix="/bin/update?">                  <chain sequency="chain3" value="fordelete">new text</chain>              </service>          </services>      </processers>  </framework>

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