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本文实例讲述了Python实现简单的多任务mysql转xml的方法。分享给大家供大家参考，具体如下：

为了需求导出的格式尽量和navicat导出的xml一致。

用的gevent，文件i/o操作会阻塞，所以并不会完全异步。

1. mysql2xml.py：

# -*- coding: utf-8 -*-
'''
Created on 2014/12/27
@author: Yoki
'''
import gevent
import pymysql
from pymysql.cursors import DictCursor
import re
import codecs
db_conn = None
def init_mysql_connect(*args, **kwargs):
  global db_conn
  db_conn = pymysql.connect(*args, **kwargs)
def list_to_xml(result_cur, key_list):
  '''
  mysql 结果集转xml，非xml标准导出方式; xml dom 不支持相同名字的node
  :param result_cur:
  :param key_list:
  :return:
  '''
  content = ''
  content += '<?xml version="1.0" encoding="UTF-8" ?>\r\n'
  content += '<RECORDS>\r\n' # root节点
  for item in result_cur:
    content += '\t<RECORD>\r\n'
    for k in key_list:
      v = item.get(k, '')
      real_value = v
      content += '\t\t<%s>%s</%s>\r\n' % (k, real_value, k)
    content += '\t</RECORD>\r\n'
  content += '</RECORDS>\r\n'
  return content
def get_table_rows(tb_name):
  '''
  获取mysql表rows
  :param tb_name:
  :return:
  '''
  global db_conn
  rows = []
  cursor = db_conn.cursor(cursor=DictCursor)
  cursor.execute('select * from %s' % tb_name)
  for row in cursor:
    rows.append(row)
  return rows
def get_table_keys(tb_name):
  '''
  获取表中字段，顺序 为创建表时的顺序
  :param tb_name:
  :return:
  '''
  global db_conn
  cursor = db_conn.cursor(cursor=DictCursor)
  cur = cursor.execute('show create table %s' % tb_name)
  if cur != 1:
    raise Exception
  for r in cursor:
    create_sql = r['Create Table']
    fields = re.findall('`(.*?)`', create_sql)
    result = []
    # 处理字段
    for i in xrange(1, len(fields)):
      field = fields[i]
      if field in result:
        continue
      result.append(field)
    return result
  return []
def mysql_to_xml(tb_name, output_dir='xml', postfix='xml'):
  '''
  mysql数据导出xml，
  :param tb_name: 数据库表名
  :param output_dir:
  :param postfix:
  :return:
  '''
  rows = get_table_rows(tb_name)
  keys = get_table_keys(tb_name)
  content = list_to_xml(rows, keys)
  fp = codecs.open('%s/%s.%s' % (output_dir, tb_name, postfix), 'w', 'utf-8')
  fp.write(content)
  fp.close()
tb_list = [
  'tb_item',
  'tb_state'
]
if __name__ == '__main__':
  init_mysql_connect(host="localhost", user='user', password="password", database='test', port=3306,
            charset='utf8')
  jobs = []
  for tb_name in tb_list:
    jobs.append(gevent.spawn(mysql_to_xml, tb_name))
  gevent.joinall(jobs)

2. list_to_xml函数修改，速度提升上百倍

def list_to_xml(result_cur, key_list):
  fp = codecs.open('test.xml'), 'w', 'utf-8')
  fp.write('<?xml version="1.0" encoding="UTF-8" ?>\r\n')
  fp.write('<RECORDS>\r\n')
  for item in result_cur:
    fp.write('\t<RECORD>\r\n')
    for k in key_list:
      v = item.get(k, '')
      if v is None:
        real_value = ''
      else:
        if type(v) == unicode:
          real_value = cgi.escape(v)
        else:
          real_value = v
      fp.write('\t\t<%s>%s</%s>\r\n' % (k, real_value, k))
    fp.write('\t</RECORD>\r\n')
  fp.write('</RECORDS>\r\n')
  fp.close()

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