几天后，SQL连接会因MySQLNonTransientConnectionException而关闭

Question

org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed

we are using JPA and connection is happening during app startup as a bean 
we have defined following properties..
# JDBC properties
spring.datasource.tomcat.initial-size=10
spring.datasource.tomcat.maxActive=30
spring.datasource.tomcat.minIdle=4
spring.datasource.tomcat.testOnBorrow=true
spring.datasource.tomcat.poolPreparedStatements=true
spring.datasource.tomcat.testWhileIdle=true
spring.datasource.timeBetweenEvictionRunsMillis = 60000
spring.datasource.validationQuery = SELECT 1

我们正在尝试在初始化过程中设置以上道具，因为这些道具会自动设置 豆创作 返回DataSourceBuilder                 。创建（）                 .url（URL）                 .username（用户名）                 .password（密码）                 .build（）;