java - 无法分配连接，因为 : User id length (0) is outside the range of 1 to 255

Question

我正在使用带有 JSF、EJB 和 JPA 的 Netbeans 创建登录界面。当我尝试部署项目时，它抛出以下异常:

Internal Exception: java.sql.SQLException: 
Error in allocating a connection. Cause: Connection could not be allocated because: User id length (0) is outside the range of 1 to 255.
Error Code: 0. Please see server.log for more details.
C:\Users\Dell\Desktop\assignmenttask2\nbproject\build-impl.xml:1033: The module has not been deployed.
See the server log for details.

这是怎么引起的，我该如何解决？

Answer 1

需要在persistence.xml中配置

<properties>
  <property name="javax.persistence.jdbc.user" value="APP"/>
  <property name="javax.persistence.jdbc.password" value="APP"/>
 </properties>

see here