u012941811的专栏

Caused by: 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 a

概念           JDBC                     Hibernate                         JPA 资源           Connection          Session                        EntityManager 资源工厂   DataSource         sessionfactory    

出处  http://blog.sina.com.cn/s/blog_4b5bc01101019vc3.html

1.对于数据库种不同的时间类型，要分别采用与之相对应的Java包装类来存取；  日期类型用java.sql.Date，时间类型用java.sql.Time，日期/时间类型用java.sql.Timestamp；  这里举个例子：假设要从oracle中获取系统时间，需要执行sql：select sysdate from dual， 然后在通过ResultSet获取查询结果时，一定要调用方法：g

出处：http://stackoverflow.com/questions/12414596/how-to-check-if-a-particular-database-in-mysql-already-exists-using-java // Connection connection = ResultSet resultSet = connection.getMetaData().ge