{"flag":false,"code":20001,"message":"Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was44584 seconds ago.The last packet sent successfully to the server was 44584 seconds ago, which  is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.","data":null}