Hibernate error: org. hibernate. Id. identifiergenerationexception: IDs for this class must be manually assig

Org. hibernate. Id. identifiergenerationexception: IDs for this class must be manually assigned before calling save ()

The cause of this error may be that your table has a primary key. But when you insert (call save), the value is null.

The ID (primary key) type in the data table you want to operate on is set to "auto-increment type ".

In hibernate. cfg. XML, the ID generation method is assigned, that is

 

<ID name = "ID" type = "integer"> <br/> <column name = "ID"/> <br/> <generator class = "assigned"/> <br/> </ID>

 

Solution:

The primary key generation method is changed to native, which features that the primary key generation method can be automatically selected based on the underlying database.

That is<ID name = "ID" type = "integer"> <br/> <column name = "ID"/> <br/> <generator class = "native"/> <br/> </ID>