python解析xml模块封装代码

有如下的xml文件：

<?xml version="1.0" encoding="utf-8" ?> 
<root> 
<childs> 
<child name='first' >1</child> 
<child value="2">2</child> 
</childs> 
</root>

下面介绍python解析xml文件的几种方法，使用python模块实现。

方式1，python模块实现自动遍历所有节点：

#!/usr/bin/env python 
# -*- coding: utf-8 -*- 
from xml.sax.handler import contenthandler 
from xml.sax import parse
class testhandle(contenthandler): 
    def __init__(self, inlist): 
        self.inlist = inlist 

    def startelement(self,name,attrs): 
        print 'name:',name, 'attrs:',attrs.keys() 

    def endelement(self,name): 
        print 'endname',name 

    def characters(self,chars): 
        print 'chars',chars 
        self.inlist.append(chars) 

             
if __name__ == '__main__': 
    lt = [] 
    parse('test.xml', testhandle(lt)) 
    print lt

结果：
[html] view plaincopy
name: root attrs: [] 
chars  

name: childs attrs: [] 
chars  

name: child attrs: [u'name'] 
chars 1 
endname child 
chars  

name: child attrs: [u'value'] 
chars 2 
endname child 
chars  

endname childs 
chars  

endname root 
[u'\n', u'\n', u'1', u'\n', u'2', u'\n', u'\n']

方式2，python模块实现获取根节点，按需查找指定节点：

#!/usr/bin/env python   
# -*- coding: utf-8 -*-   
from xml.dom import minidom   
xmlstr = '''''<?xml version="1.0" encoding="utf-8"?>
<hash>
    <request name='first'>/2/photos/square/type.xml</request>
    <error_code>21301</error_code>
    <error>auth faild!</error>
</hash>
''' 
def doxml(xmlstr): 
    dom = minidom.parsestring(xmlstr)     
    print 'dom:'     
    print dom.toxml()   

    root = dom.firstchild     
    print 'root:'     
    print root.toxml()   

    childs = root.childnodes   
    for child in childs: 
        print child.toxml() 
        if child.nodetype == child.text_node: 
            pass 
        else: 
            print 'child node attribute name:', child.getattribute('name') 
            print 'child node name:', child.nodename 
            print 'child node len:',len(child.childnodes) 
            print 'child data:',child.childnodes[0].data 
            print '=======================================' 
            print 'more help info to see:' 
            for med in dir(child): 
                print help(med)     

               
if __name__ == '__main__':   
    doxml(xmlstr)

结果：
[html] view plaincopy
dom: 
<?xml version="1.0" ?><hash> 
    <request name="first">/2/photos/square/type.xml</request> 
    <error_code>21301</error_code> 
    <error>auth faild!</error> 
</hash> 
root: 
<hash> 
    <request name="first">/2/photos/square/type.xml</request> 
    <error_code>21301</error_code> 
    <error>auth faild!</error> 
</hash> 

<request name="first">/2/photos/square/type.xml</request> 
child node attribute name: first 
child node name: request 
child node len: 1 
child data: /2/photos/square/type.xml 
======================================= 
more help info to see: 
两种方法各有其优点，python的xml处理模块太多，目前只用到这2个。

=====补充分割线================
实际工作中发现python的mimidom无法解析其它编码的xml，只能解析utf-8的编码，而其xml文件的头部申明也必须是utf-8，为其它编码会报错误。
网上的解决办法都是替换xml文件头部的编码申明，然后转换编码为utf-8再用minidom解码，实际测试为可行，不过有点累赘的感觉。

本节是 python解析xml模块封装代码 的第二部分。
====写xml内容的分割线=========

#!\urs\bin\env python 
#encoding: utf-8 
from xml.dom import minidom 

class xmlwrite: 
    def __init__(self, resultfile): 
        self.resultfile = resultfile 
        self.rootname = 'api' 
        self.__create_xml_dom() 

    def __create_xml_dom(self): 
        xmlimpl = minidom.getdomimplementation() 
        self.dom = xmlimpl.createdocument(none, self.rootname, none) 
        self.root = self.dom.documentelement 

    def __get_spec_node(self, xpath): 
        patharr = xpath.split(r'/') 
        parentnode = self.root 
        exist = 1 
        for nodename in patharr: 
            if nodename.strip() == '': 
                continue 
            if not exist: 
                return none 
            spcindex = nodename.find('[') 
            if spcindex > -1: 
                index = int(nodename[spcindex+1:-1]) 
            else: 
                index = 0 
            count = 0 
            childs = parentnode.childnodes 
            for child in childs: 
                if child.nodename == nodename[:spcindex]: 
                    if count == index: 
                        parentnode = child 
                        exist = 1 
                        break 
                    count += 1 
                    continue 
                else: 
                    exist = 0 
        return parentnode 

         
    def write_node(self, parent, nodename, value, attribute=none, cdata=false): 
        node = self.dom.createelement(nodename) 
        if value: 
            if cdata: 
                nodedata = self.dom.createcdatasection(value) 
            else: 
                nodedata = self.dom.createtextnode(value) 
            node.appendchild(nodedata) 
            if attribute and isinstance(attribute, dict): 
                for key, value in attribute.items(): 
                    node.setattribute(key, value)    
        try: 
            parentnode = self.__get_spec_node(parent) 
        except: 
            print 'get parent node fail, use the root as parent node' 
            parentnode = self.root 
        parentnode.appendchild(node) 

     
    def write_start_time(self, time): 
        self.write_node('/','starttime', time) 

    def write_end_time(self, time): 
        self.write_node('/','endtime', time)     

    def write_pass_count(self, count): 
        self.write_node('/','passcount', count)    

    def write_fail_count(self, count): 
        self.write_node('/','failcount', count)    

    def write_case(self): 
        self.write_node('/','case', none)    

    def write_case_no(self, index, value): 
        self.write_node('/case[%s]/' % index,'no', value) 

    def write_case_url(self, index, value): 
        self.write_node('/case[%s]/' % index,'url', value) 

    def write_case_dbdata(self, index, value): 
        self.write_node('/case[%s]/' % index,'dbdata', value) 

    def write_case_apidata(self, index, value): 
        self.write_node('/case[%s]/' % index,'apidata', value) 

    def write_case_dbsql(self, index, value): 
        self.write_node('/case[%s]/' % index,'dbsql', value, cdata=true) 

    def write_case_apixpath(self, index, value): 
        self.write_node('/case[%s]/' % index,'apixpath', value)        

    def save_xml(self): 
        myfile = file(self.resultfile, 'w') 
        self.dom.writexml(myfile, encoding='utf-8') 
        myfile.close() 

if __name__ == '__main__': 
      xr = xmlwrite(r'd:\test.xml') 
      xr.write_start_time('2223') 
      xr.write_end_time('444')       
      xr.write_pass_count('22') 
      xr.write_fail_count('33')   
      xr.write_case() 
      xr.write_case() 
      xr.write_case_no(0, '0') 
      xr.write_case_url(0, 'http://www.google.com')    
      xr.write_case_url(0, 'http://www.google.com')    
      xr.write_case_dbsql(0, 'select * from ') 
      xr.write_case_dbdata(0, 'dbtata') 
      xr.write_case_apixpath(0, '/xpath') 
      xr.write_case_apidata(0, 'apidata') 
      xr.write_case_no(1, '1')        
      xr.write_case_url(1, 'http://www.baidu.com')    
      xr.write_case_url(1, 'http://www.baidu.com')    
      xr.write_case_dbsql(1, 'select 1 from ') 
      xr.write_case_dbdata(1, 'dbtata1') 
      xr.write_case_apixpath(1, '/xpath1') 
      xr.write_case_apidata(1, 'apidata1') 
      xr.save_xml()

以上封装了minidom，支持通过xpath来写节点，不支持xpath带属性的匹配，但支持带索引的匹配。
比如：/root/child[1], 表示root的第2个child节点。