Python实现简单的多任务mysql转xml的方法

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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