Question

Tomcat6配置mysql的连接池，老是报错

<Resource name="orcl_cr21" auth="Container" type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="100"
username="root" password="cr21" driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/cr21"/>

操作错误，请重新操作!
方法名：'execute';
错误信息：Hibernate operation: Cannot open connection; uncategorized SQLException for SQL [???]; SQL state [null]; error code [0]; Cannot create PoolableConnectionFactory (Communications link failure The last packet successfully received from the server was 1,365,384,179,140 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.); nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure The last packet successfully received from the server was 1,365,384,179,140 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.)

Answer 1

url="jdbc:mysql://localhost:3306/cr21"/>改为url="jdbc:mysql://localhost:3306/数据库的名字"/>

并在cmd中输入netstat -ano查看端口占用情况，查看是否有被占用的3306端口，若没有则把 localhost端口该成占用着的端口，若有占用的端口为3307，则改为url="jdbc:mysql://localhost:3307/数据库的名字"/>

供以后查找这个问题的人方便

Answer 2

你的连接MYSQL的JDBC的JAR包是不是版本有问题

追问

jar包应该是啥名

追答

连接MYSQL的JDBC的JAR包有好多版本，是不是你数据库的版本和你JAR包的版本不一致