实例Python处理XML文件的方法

需求
有一个表，里面数据量比较大，每天一更新，其字段可以通过xml配置文件进行配置，即，可能每次建表的字段不一样。

上游跑时会根据配置从源文件中提取，到入库这一步需要根据配置进行建表。

解决
写了一个简单的xml，配置需要字段及类型

上游读取到对应的数据

入库这一步，先把原表删除，根据配置建新表

XML文件

<?xml version="1.0" encoding="UTF-8"?><!-- 表名 ,数据库名  可灵活配置插入哪个库哪个表 --><table name="top_query" db_name="evaluting_sys"><!-- 非业务主键，自增长,可配名，其他 INTEGER UNSIGNED AUTO_INCREMENT --><primary_key><name>id</name></primary_key><!-- 字段开始 --><field><name>query</name><type>varchar(200)</type><is_index>false</is_index><description>query</description></field><field><name>pv</name><type>integer</type><is_index>false</is_index><description>pv</description></field><field><name>avg_money</name><type>integer</type><is_index>false</is_index><description></description></field><!-- 字段配置结束 --></table>

处理脚本

#!/usr/bin/python/' target='_blank'>python# -*- coding:utf-8 -*-#author: wklken#desc: use to read db xml config.#-----------------------#2012-02-18 created#----------------------import sys,osfrom xml.dom import minidom, Nodedef read_dbconfig_xml(xml_file_path):  content = {}  root = minidom.parse(xml_file_path)  table = root.getElementsByTagName("table")[0]  #read dbname and table name.  table_name = table.getAttribute("name")  db_name = table.getAttribute("db_name")  if len(table_name) > 0 and len(db_name) > 0:    db_sql = "create database if not exists `" + db_name +"`; use " + db_name + ";"    table_drop_sql = "drop " + table_name + " if exists " + table_name + ";"    content.update({"db_sql" : db_sql})    content.update({"table_sql" : table_drop_sql })  else:    print "Error:attribute is not define well! db_name=" + db_name + " ;table_name=" + table_name    sys.exit(1)  #print table_name, db_name  table_create_sql = "create table " + table_name +"("  #read primary cell  primary_key = table.getElementsByTagName("primary_key")[0]  primary_key_name = primary_key.getElementsByTagName("name")[0].childNodes[0].nodeValue  table_create_sql += primary_key_name + " INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY,"  #print primary_key.toxml()  #read ordernary field  fields = table.getElementsByTagName("field")  f_index = 0  for field in fields:    f_index += 1    name = field.getElementsByTagName("name")[0].childNodes[0].nodeValue    type = field.getElementsByTagName("type")[0].childNodes[0].nodeValue    table_create_sql += name + " " + type    if f_index != len(fields):    table_create_sql += ","    is_index = field.getElementsByTagName("is_index")[0].childNodes[0].nodeValue  table_create_sql += ");"  content.update({"table_create_sql" : table_create_sql})  #character set latin1 collate latin1_danish_ci;  print contentif __name__ == "__main__":read_dbconfig_xml(sys.argv[1])

Python解析XML大文件[SAX]
需求
读取xml数据文件，文件较大，需要实时处理插入到数据库

xml文档

<PERSONS><person>  <id>100000</id>  <sex>男</sex>  <address>北京，海淀区</address>  <fansNum>437</fansNum>  <summary>1989</summary>  <wbNum>333</wbNum>  <gzNum>242</gzNum>  <blog>null</blog>  <edu>大学</edu>  <work></work>  <renZh>1</renZh>  <brithday>2月14日</brithday></person></PERSONS>

处理
sax处理时并不会像dom一样可以以类似节点的维度进行读取,它只有 开始标签 内容 结束标签 之分

处理思想是：通过一个handler，对开始标签，内容，结束标签各有一个处理函数

代码及注解
person 处理类

from xml.sax import handler,parseStringclass PersonHandler(handler.ContentHandler): def __init__(self, db_ops):  #db op obj  self.db_ops = db_ops  #存储一个person的map  self.person = {}  #当前的tag  self.current_tag = ""  #是否是tag之间的内容 ，目的拿到tag间内容，不受空白的干扰  self.in_quote = 0 #开始，清空map def startElement(self, name, attr):  #以person，清空map  if name == "person":   self.person = {}  #记录 状态  self.current_tag = name  self.in_quote = 1 #结束，插入数据库 def endElement(self, name):  #以person结尾 代表读取一个person的信息结束  if name == "person":   #do something   in_fields = tuple([ ('"' + self.person.get(i,"") + '"') for i in fields ])   print in_sql % in_fields   db_ops.insert( in_sql%(in_fields))  #处理  self.in_quote = 0 def characters(self, content):  #若是在tag之间的内容，更新到map中  if self.in_quote:   self.person.update({self.current_tag: content})

加上入库的完整代码

#!/usr/bin/python# -*- coding:utf-8 -*-#parse_person.py#version : 0.1#author : wukunliang@163.com#desc : parse person.xml and out sqlimport sys,osimport mysql/' target='_blank'>mysqldbreload(sys)sys.setdefaultencoding('utf-8')in_sql = "insert into person(id,sex,address,fansNum,summary,wbNum,gzNum,blog,edu,work,renZh,brithday) values(%s, %s, %s, %s, %s, %s,     %s, %s, %s, %s, %s, %s)"fields = ("id","sex","address","fansNum","summary","wbNum","gzNum","blog","edu","work","renZh","brithday")#数据库方法class Db_Connect:  def __init__(self, db_host, user, pwd, db_name, charset="utf8", use_unicode = True):    print "init begin"    print db_host, user, pwd, db_name, charset , use_unicode    self.conn = MySQLdb.Connection(db_host, user, pwd, db_name, charset=charset , use_unicode=use_unicode)    print "init end"  def insert(self, sql):    try:      n = self.conn.cursor().execute(sql)      return n    except MySQLdb.Warning, e:      print "Error: execute sql '",sql,"' failed"  def close(self):    self.conn.close()#person 处理类from xml.sax import handler,parseStringclass PersonHandler(handler.ContentHandler):  def __init__(self, db_ops):    #db op obj    self.db_ops = db_ops    #存储一个person的map    self.person = {}    #当前的tag    self.current_tag = ""    #是否是tag之间的内容    self.in_quote = 0  #开始，清空map  def startElement(self, name, attr):    #以person，清空map    if name == "person":     self.person = {}    #记录 状态    self.current_tag = name    self.in_quote = 1  #结束，插入数据库  def endElement(self, name):    #以person结尾 代表读取一个person的信息结束    if name == "person":      #do something      in_fields = tuple([ ('"' + self.person.get(i,"") + '"') for i in fields ])      print in_sql % in_fields      db_ops.insert( in_sql%(in_fields))    #处理    self.in_quote = 0  def characters(self, content):    #若是在tag之间的内容，更新到map中    if self.in_quote:      self.person.update({self.current_tag: content})if __name__ == "__main__":  f = open("./person.xml")  #如果源文件gbk 转码   若是utf-8，去掉decode.encode  db_ops = Db_Connect("127.0.0.1", "root", "root", "test")  parseString(f.read().decode("gbk").encode("utf-8"), PersonHandler(db_ops))  f.close()  db_ops.close()