Hibernate java. Lang. nullpointerexception Solution

When I was working on a project and calling data in isubitemdao, the problem of hibernate java. Lang. nullpointerexception always occurred, and the page cannot be displayed. Then I checked the following online and saw the following message:
Check the configuration file.
For example, in Struts-config, whether the action name and path are consistent with those registered in spring. Pay special attention to Case sensitivity. Whether the HBM file configuration is incorrect, Which is case sensitive...

Therefore, I checked the following applicationcontext carefully and lost my head. I didn't load the DaO file. This is the result of carelessness!