python 长连接mysql实例

##起因
最近处理数据库里的数据，有余数据太大，不可能采用短连接，只能采用长连接了。所以写了个这个
参考资料
https://www.polarxiong.com/archives/Python-mysql-connector中获取数据库值的一些问题.html
https://blog.csdn.net/wzm112/article/details/7745835

from mysql import connector
import time

class mysql_connect:
    def __init__(self,
                 host='',
                 user='',
                 passwd='',
                 db='',
                 port=3306,
                 charset='utf8mb4'
                 ):
        self.host = host
        self.user = user
        self.passwd = passwd
        self.db = db
        self.port = port
        self.charset = charset
        self.conn = None
        self.cursor = None
        self._conn()

    def _conn(self):
        try:
            self.conn = connector.connect(host=self.host,
                                          user=self.user,
                                          password=self.passwd,
                                          database=self.db,
                                          port=self.port)
            return True
        except:
            return False

    def _cursor(self):
        self.cursor = self.conn.cursor(dictionary=True)
        self.cursor.execute("set names '{}'".format(self.charset))

    def _free(self):
        self.cursor.close()

    def _reConn(self, num=28800, stime=3):  # 重试连接总次数为1天,这里根据实际情况自己设置,如果服务器宕机1天都没发现就......
        _number = 0
        _status = True
        while _status and _number <= num:
            try:
                self.conn.ping()  # cping 校验连接是否异常
                _status = False
            except:
                if self._conn() == True:  # 重新连接,成功退出
                    _status = False
                    break
                _number += 1
                time.sleep(stime)  # 连接不成功,休眠3秒钟,继续循环，知道成功或重试次数结束

    def select(self, sql=''):
        try:
            self._reConn()
            self._cursor()
            self.cursor.execute(sql)
            result = self.cursor.fetchall()
            self._free()
            return result
        except Exception as e:
            # print "Error %d: %s" % (e.args[0], e.args[1])
            return False

    def query(self, sql=''):
        try:
            self._reConn()
            self._cursor()
            result = self.cursor.execute(sql)
            self.conn.commit()
            self._free()
            return (True, result)
        except Exception as e:
            return False

    def close(self):
        self.conn.close()

if __name__ == "__main__":
    conn = mysql_connect(host="localhost",
                         user="root",
                         passwd="root",
                         db="test")

    data = conn.select("select id from shop_customer limit 10")
    print(data)