通过xpath读取xml节点

#!/usr/bin/python
#encoding:utf-8

from xml.dom import minidom

class xmlwrite:
    def __init__(self,resultfile):
        self.resultfile = resultfile
        self.dom = minidom.parse(self.resultfile)

    def get_node_with_xpath(self,xpath):
        patharr = xpath.split(r'/')
        parentnode = self.dom
        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])
                nodename = nodename[:spcindex]
            else:
                index = 0
            count = 0
            childs = parentnode.childNodes
            for child in childs:
                if child.nodeName == nodename:
                    if count == index:
                        parentnode = child
                        exist = 1
                        break
                    count += 1
                    continue
                else:
                    exist = 0
        if exist==1:
            return parentnode

if __name__ == '__main__':
    xr = xmlwrite(r'e:/test.xml')
    xpath = u'/api/Case[1]/No'
    node = xr.get_node_with_xpath(xpath)
    if node:
        print node.toprettyxml()
    else:
        print 'can\'t find with xpath:',xpath