7

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：（部分代码清除我的疑问，直到开始元素功能）

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

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'))

result : 上述打印语句的结果如下所示

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>

正如您在上面看到的那样，我从 print 语句中获取name和获取attrs，但现在我的全部意图是获取该名称的值，如何获取上面所有这些标签的值，因为我只获取节点名称而不是值。

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

4

4 回答 4

9

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

def characters(self, data):
    print data

但是请注意这一点：解析器不需要在一个块中为您提供所有数据。您应该使用内部缓冲区并在需要时读取它。在我的大部分 xml/sax 代码中，我执行以下操作：

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职位描述的文件并想要一个包含职位的列表，其中每个职位都是字段的字典，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

如果您一次只需要解析一个作业，您可以简化列表部分并丢弃该startElement方法 - 只需将 _result 设置为 dict 并直接在endElement.

于 2012-09-04T12:18:12.157 回答
3

要获取节点的文本内容，需要实现 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）

于 2012-09-04T12:16:08.167 回答
2

我建议使用 pulldom。这允许您使用 sax 解析器加载 doc，当您找到感兴趣的节点时，仅将该节点加载到 dom 片段中。

这是一篇关于使用它的一些示例的文章：https ://www.ibm.com/developerworks/xml/library/x-tipulldom/index.html

于 2012-09-04T12:21:50.017 回答
2

您还需要实现一个characters处理程序：

def characters(self, content):
    print content

但这可能会为您提供块中的文本，而不是每个标签一个块。

不过，请帮自己一个大忙，改用ElementTree API；该 API 远比 XML DOM API 更 Pythononic 且更易于使用。

from xml.etree import ElementTree as ET

etree = ET.parse('/path/to/xml_file.xml')
jobtitle = etree.find('job/title').text

如果您想要的只是直接转换为字典，请查看这个方便的 ActiveState Python Cookbook 食谱：将 XML 转换为字典并返回。请注意，它也使用 ElementTree API。

如果您有一组想要查找的现有元素，只需在find()方法中使用这些元素：

fieldnames = [
    'title', 'job-code', 'detail-url', 'job-category', 'description',
    'summary', 'posted-date', 'location', 'address', 'city', 'state',
    'zip', 'country', 'company', 'name', 'url']
fields = {}

etree = ET.parse('/path/to/xml_file.xml')

for field in fieldnames:
    elem = etree.find(field)
    if field is not None and field.text is not None:
        fields[field] = elem.text
于 2012-09-04T12:16:59.740 回答