Exception occurred during processing request: null java.lang.NullPointerException

Exception occurred during processing request: null
java.lang.NullPointerException
    at kongque.service.impl.UnitServiceimpl.datagrid(UnitServiceimpl.java:46)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

发现在DAO层