如何在python中从xml sax解析器获取结果

Question

我正在使用xml sax解析器来解析xml文件,下面是我的代码

xml文件代码:

<job>
    <title>Registered Nurse-Epilepsy</title>
    <job-code>881723</job-code>
    <detail-url>http://search.careers-hcanorthtexas.com/s/Job-Details/Registered-Nurse-Epilepsy-Job/Medical-City/xjdp-cl289619-jf120-ct2181-jid4041800?s_cid=Advance
    </detail-url>
    <job-category>Neuroscience Nursing</job-category>
    <description>
        <summary>
            <div class='descriptionheader'>Description</div><P STYLE="margin-top:0px;margin-bottom:0px"><SPAN STYLE="font-family:Arial;font-size:small">Utilizing the standards set forth for Nursing Practice by the ANA and ONS, the RN will organize, modify, evaluate, document and maintain the plan of care for Epilepsy and/or Neurological patients. It will include individualized, family centered, holistic, supportive, and safe age-specific care.</SPAN></P><div class='qualificationsheader'>Qualifications</div><UL STYLE="list-style-type:disc"> <LI>Graduate of an accredited school of Professional Nursing.</LI> <LI>BSN preferred </LI> <LI>Current licensure with the Board of Nurse Examiners for the State of Texas</LI> <LI>Experience in Epilepsy Monitoring and/or Neurological background preferred.</LI> <LI>ACLS preferred, within 6 months of hire</LI> <LI>PALS required upon hire</LI> </UL>
       </summary>
    </description>
    <posted-date>2012-07-26</posted-date>
    <location>
       <address>7777 Forest Lane</address>
       <city>Dallas</city>
       <state>TX</state>
       <zip>75230</zip>
       <country>US</country>
    </location>
    <company>
       <name>Medical City (Dallas, TX)</name>
      <url>http://www.hcanorthtexas.com/careers/search-jobs.dot</url>
    </company>
</job> 

Python代码 :(部分代码清除我的怀疑直到启动元素功能)

from xml.sax.handler import ContentHandler
import xml.sax
import xml.parsers.expat
import ConfigParser
import xml.sax

class Exact(xml.sax.handler.ContentHandler):
  def __init__(self):
    self.curpath = []

  def startElement(self, name, attrs):
    print name,attrs
    self.clearFields()


  def endElement(self, name):
    pass

  def characters(self, data):
    self.buffer += data

  def clearFields():
    self.fields = {}
    self.fields['title'] = None
    self.fields['job-code'] = None
    self.fields['detail-url'] = None
    self.fields['job-category'] = None
    self.fields['description'] = None
    self.fields['summary'] = None
    self.fields['posted-date'] = None
    self.fields['location'] = None
    self.fields['address'] = None
    self.fields['city'] = None
    self.fields['state'] = None
    self.fields['zip'] = None
    self.fields['country'] = None
    self.fields['company'] = None
    self.fields['name'] = None
    self.fields['url'] = None

    self.buffer = ''

if __name__ == '__main__':
  parser = xml.sax.make_parser()
  handler = Exact()
  parser.setContentHandler(handler)
  parser.parse(open('/path/to/xml_file.xml'))

结果:上面的打印声明的结果如下

job     <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
title   <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
job-code <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
detail-url <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
job-category <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
description  <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
summary       <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
posted-date   <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
location      <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
address       <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
city          <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
state         <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
zip           <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
country       <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
company       <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
name          <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>
url           <xml.sax.xmlreader.AttributesImpl instance at 0x2c0ba70>

正如你可以看到上面我得到name和attrs从打印语句,但现在我的全部意图是让这个名字,怎么上面,因为我只得到节点的名称,但不是所有的值这些标签读取值的值.

编辑代码:

我真的很困惑如何将数据从节点映射到字典中的键,如上所述

Answer 1

要获取元素的内容,您需要覆盖该characters方法...将此添加到您的处理程序类:

def characters(self, data):
    print data

但要注意这一点:解析器不需要在一个块中提供所有数据.您应该使用内部缓冲区并在需要时读取它.在我的大多数xml/sax代码中,我做了类似这样的事情:

class MyHandler(xml.sax.handler.ContentHandler):
    def __init__(self):
        self._charBuffer = []

    def _flushCharBuffer(self):
        s = ''.join(self._charBuffer)
        self._charBuffer = []
        return s

    def characters(self, data):
        self._charBuffer.append(data)

...然后在我需要数据的元素末尾调用flush方法.

对于您的整个用例 - 假设您有一个包含多个作业描述的文件,并且想要一个包含每个作业的作业的列表是字段的字典,请执行以下操作:

class MyHandler(xml.sax.handler.ContentHandler):
    def __init__(self):
        self._charBuffer = []
        self._result = []

    def _getCharacterData(self):
        data = ''.join(self._charBuffer).strip()
        self._charBuffer = []
        return data.strip() #remove strip() if whitespace is important

    def parse(self, f):
        xml.sax.parse(f, self)
        return self._result

    def characters(self, data):
        self._charBuffer.append(data)

    def startElement(self, name, attrs):
        if name == 'job': self._result.append({})

    def endElement(self, name):
        if not name == 'job': self._result[-1][name] = self._getCharacterData()

jobs = MyHandler().parse("job-file.xml") #a list of all jobs

如果您只需要一次解析一个作业,则可以简化列表部分并丢弃该startElement方法 - 只需将_result设置为dict并直接分配给它endElement.

Answer 2

要获取节点的文本内容，需要实现一个characters方法。例如

class Exact(xml.sax.handler.ContentHandler):
  def __init__(self):
    self.curpath = []

  def startElement(self, name, attrs):
    print name,attrs


  def endElement(self, name):
    print 'end ' + name

  def characters(self, content):
    print content

会输出：

job <xml.sax.xmlreader.AttributesImpl instance at 0xb6d9baec>



title <xml.sax.xmlreader.AttributesImpl instance at 0xb6d9bb0c>
Registered Nurse-Epilepsy
end title



job-code <xml.sax.xmlreader.AttributesImpl instance at 0xb6d9bb2c>
881723
end job-code



detail-url <xml.sax.xmlreader.AttributesImpl instance at 0xb6d9bb2c>
http://search.careers-hcanorthtexas.com/s/Job-Details/Registered-Nurse-Epilepsy-Job/Medical-City/xjdp-cl289619-jf120-ct2181-jid4041800?s_cid=Advance



end detail-url

（狙击）