异常1：not-
null property references a null or transient value
解决方法：将“一对多”关系中的“一”方，
not-null设置为
false
异常2：org.hibernate.TransientObjectException: object
references an unsaved
transient instance
解决方法：
cascade="save-update,persist"
异常3：org.hibernate.QueryException: could not resolve
property
解决方法："from Category category where
category.userID = :userID"修改为"from Category category where
userID = :userID"或者"from Category category where
category.user.id = :userID"
异常4：could not initialize proxy - the owning Session was closed
解决方法：设置
lazy为
false
另一种解决方案：
org.hibernate.PropertyValueException:
not-null property references a null or transient value:
com.bjcx.project.entity.task.Equipmenttable.ProjPortfolioID
at org.hibernate.engine.Nullability.checkNullability(Nullability.java:72)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate
字面意思：一个不允许为Null的属性引用了一个为Null的或者无效的值。
原因：在***.hbm.xml中的
<property name="ProjPortfolioID" column="ProjPortfolioID"
type="big_decimal" not-null="true" length="10" />
中，not-null="true",这说明属性ProjPortfolioID 不允许为空，而在ActionForm中未给他赋值，则就为空，所以就会报错！