jpa出现“未知数据库'mydb'”错误

Question

我正在尝试连接到 mysql 服务器但收到此错误。当 mydb 是系统中的唯一名称时。请告诉我哪里错了...

我的持久化 xml 如下：

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
 version="1.0">

 <persistence-unit name="MyPersistenceUnit">

  <provider>org.hibernate.ejb.HibernatePersistence</provider>

  <properties>
   <property name="hibernate.archive.autodetection" value="class" />
   <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
   <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/mydb" />
   <property name="hibernate.connection.username" value="root" />
   <property name="hibernate.connection.password" value="tft" />
   <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />

   <property name="hibernate.hbm2ddl.auto" value="create" />

   <property name="hibernate.show_sql" value="true" />
   <property name="hibernate.format_sql" value="true" />
   <property name="hibernate.use_sql_comments" value="true" />
  </properties>

 </persistence-unit>
</persistence>

Answer 1

1.你必须检查你的mysql jdbc驱动

2.你必须检查mysql服务器的状态和用户名和密码的验证。