郑州给公司做网站的公司/如何建立网址

先来看查看效果:

 

 

在代码连接数据库后，并且执行三条sql后，将mysql直接重启掉，故我们的连接池连接均是不ok的，所以，它会全部删除再抓新的连接下来，重启mysql命令:

 

 

关于python代码:

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-import pymysql
import random
import time# 初始化mysql 连接池
def MySQLInit(mysql_host,mysql_port,mysql_user,mysql_password,mysql_charset,mysql_dbname,mysql_maxconnect):# 定义返回mysql连接池的类型，这里定义为 list     return_db_list = []for Connect in range(0,mysql_maxconnect):try:db = pymysql.connect(host = mysql_host , port = mysql_port , user = mysql_user , passwd = mysql_password ,db = mysql_dbname ,charset = mysql_charset )print ("连接MySQL数据库成功，MySQL数据库ID为:%s" %(db))return_db_list.append(db)except Exception as e:print ("连接MySQL数据库出错")print (e)# 如果mysql连接池为空，则返回-1if 0 == len(return_db_list):print ("错误 , 连接MySQL数据库失败,连接池为0")return -1else:# 返回mysql连接池return return_db_listdef Pull_DB_Connect(mysql_host,mysql_port,mysql_user,mysql_password,mysql_charset,mysql_dbname , MySQL_Connect_Pool , mysql_maxconnect) :# 打印补充前的mysql连接数print ("补充前MySQL连接数为:",len(MySQL_Connect_Pool))# 循环相差的连接数for Connect in range((len(MySQL_Connect_Pool)) , mysql_maxconnect):try:db = pymysql.connect(host = mysql_host , port = mysql_port , user = mysql_user , passwd = mysql_password ,db = mysql_dbname ,charset = mysql_charset )print ("重新补充，连接MySQL数据库成功，MySQL数据库ID为:%s" %(db))# 将刚刚连接成功的DB连接追加到MySQL_Connect_Pool中
            MySQL_Connect_Pool.append(db)except Exception as e:print ("重新补充，连接MySQL数据库出错")print (e)if 0 == len(MySQL_Connect_Pool):print ("错误 , 连接MySQL数据库失败,连接池为0")return -1else:# 打印连接池总数并且返回print("Mysql 连接池总数为:" , len(MySQL_Connect_Pool))return MySQL_Connect_Pool def main() :# 定义测试mysql信息mysql_host = "192.168.1.100"mysql_port = 3306mysql_user = "liwang" mysql_password = "liwang"mysql_charset = "utf8"mysql_dbname = "itchat"mysql_maxconnect = 3# 初始化mysql连接池MySQL_Connect_Pool = MySQLInit(mysql_host,mysql_port,mysql_user,mysql_password,mysql_charset,mysql_dbname,mysql_maxconnect)# 定义初始化sql sql = "show databases;"while True:# 随机获连接池的下标db_link = random.randint(0,len(MySQL_Connect_Pool)-1)try:# 执行sql cursor = MySQL_Connect_Pool[db_link].cursor()cursor.execute(sql)print (cursor.fetchall())except Exception as e:# 如果执行失败，模拟为DB连接失效，则打印错误信息，删除错误的MySQL_Connect_Pool信息print (e)del MySQL_Connect_Pool[db_link]print ("数据库无法连接，删除Mysql连接池下标:" , db_link)# 重新补充mysql连接池
            Pull_DB_Connect(mysql_host,mysql_port,mysql_user,mysql_password,mysql_charset,mysql_dbname,MySQL_Connect_Pool,mysql_maxconnect)# 休眠10s time.sleep(10)if __name__ == "__main__" :main()