python中minidom对xml的常用处理

#_*_encoding:utf-8_*_

# -- seanyxie  2012.3.23 --

# ===minidom操作XML代码示例
import xml
from xml.dom import minidom
import codecs

# ==由于minidom默认的writexml()函数在读取一个xml文件后，修改后重新写入如果加了newl='\n',会将原有的xml中写入多余的行
#　 ==因此使用下面这个函数来代替
def fixed_writexml(self, writer, indent="", addindent="", newl=""):
    # indent = current indentation
    # addindent = indentation to add to higher levels
    # newl = newline string
    writer.write(indent+"<" + self.tagName)

    attrs = self._get_attributes()
    a_names = attrs.keys()
    a_names.sort()

    for a_name in a_names:
        writer.write(" %s=\"" % a_name)
        minidom._write_data(writer, attrs[a_name].value)
        writer.write("\"")
    if self.childNodes:
        if len(self.childNodes) == 1 \
          and self.childNodes[0].nodeType == minidom.Node.TEXT_NODE:
            writer.write(">")
            self.childNodes[0].writexml(writer, "", "", "")
            writer.write("</%s>%s" % (self.tagName, newl))
            return
        writer.write(">%s"%(newl))
        for node in self.childNodes:
            if node.nodeType is not minidom.Node.TEXT_NODE:
                node.writexml(writer,indent+addindent,addindent,newl)
        writer.write("%s</%s>%s" % (indent,self.tagName,newl))
    else:
        writer.write("/>%s"%(newl))

minidom.Element.writexml = fixed_writexml


def opXml():
    # =====从一个空xml文档开始
    impl = xml.dom.getDOMImplementation()
    dom = impl.createDocument(None,'All_Students',None)
    root = dom.documentElement
    # --创建一个节点，并添加到root下
    student = dom.createElement('student')
    root.appendChild(student)
    # --创建一个子节点，并设置属性
    nameE = dom.createElement('name')
    value = u'陈奕迅'
    nameE.setAttribute("attr",value)
    nameN = dom.createTextNode(value)
    nameE.appendChild(nameN)
    student.appendChild(nameE)

    # -- 写进文件,如果出现了unicode，指定文件的编码
    f = codecs.open('1.xml','w','utf-8')
    dom.writexml(f,addindent='  ',newl='\n',encoding = 'utf-8')
    f.close()

    #=====处理一个已经存在的xml文档
    dom = xml.dom.minidom.parse("1.xml")
    root = dom.documentElement
    #  -- 重新设置属性
    # --- 返回所有node name为student的节点
    allnodes = dom.getElementsByTagName('student')
    value = u'王力宏'
    for node in allnodes:
        node.setAttribute('name',value)
    # --删除节点属性
    for node in allnodes:
        node.removeAttribute('name')
    # --每个节点有 nodeType,nodeName,和nodeVaulue 等属性
    # --对于textNode，想得到它的文本内容可以使用: .data属性
        print node.nodeType,node.nodeValue
    # --也可以删除节点
        root.removeChild(node)
    f = codecs.open('1.xml','w','utf-8')
    dom.writexml(f,addindent='  ',newl='\n',encoding = 'utf-8')
    f.close()


if __name__=='__main__':
    opXml()

上面的代码包含了python中minidom操作xml的常用操作