服务器环境中 JAVA 连接数据库 Communications link failure, Contection refused 网上很多这种情况,解决基本上是将127.0.0.1换成localhost 但是我这个比较傻b,原因也很无奈.值得纪念,以下是我解决的过程,过程还是值得学习的. 1.症状:java 连接数据库 访问拒绝 连接拒绝. 原因:基本上是围绕着 IP,PORT,DB,USERNAME,PASSWORD这几个参数,只能是这里出了问题. 过程:将127.0.0.1换成localh…

最近在用一个MySQL的Java连接池的过程中,连接一晚上不释放,第二天就会造成超时的错误,查了一下原因,原来是因为MySQL默认的空闲等待时间是8个小时,一旦空闲超过8个小时,就会抛出异常.异常文本如下: com.mysql.jdbc.CommunicationsException MESSAGE: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.net.Soc…

使用Connector/J连接MySQL数据库,程序运行较长时间后就会报以下错误: Communications link failure,The last packet successfully received from the server was *** millisecond ago.The last packet successfully sent to the server was *** millisecond ago. 其中错误还会提示你修改wait_timeout或是使用Co…

现象:客户端连接服务器端mysql是没问题的,所有都木有问题,应用程序配置也没问题,但是连接就抛异常: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets f…

现象: 报错:Exception in thread "main" com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure 解决办法: 更换 mysql-connector-java-8.0.11.jar 为 mysql-connector-java-8.0.16.jar, 下载位置:https://mvnrepository.com/artifact/mysql/mysql-c…

09:00:30.307 [http-8080-6] ERROR org.hibernate.transaction.JDBCTransaction -JDBC begin failed com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet successfully received from the server was 56,237,340 mi…

很长的报错,截取   ERROR c.a.d.p.DruidDataSource - discard connection   com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure       The last packet successfully received from the server was 44,866 milliseconds ago. The last pac…

报错: MySQL第二天早上第一次连接超时报错, com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure 原因: 上述问题是由mysql5数据库的配置引起的.mysql5将其连接的等待时间(wait_timeout .interactive_timeout)缺省为8小时.在其客户程序中可以这样来查看其值: mysql> show global variables like 'wait…

问题现象 com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. I spend some days to solve this…

感谢大佬:https://blog.csdn.net/a704397849/article/details/93797529 springboot + mybatis多数据库 + druid连接池配置成功.正常运行后,访问第一个数据库后访问第二个数据库,再去访问第一个数据库 会报错: Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications lin…