org.hibernate.InstantiationException: No default constructor for entity:

报错：

org.hibernate.InstantiationException: No default constructor for entity: org.ht.pojo.Dept
at org.hibernate.tuple.PojoInstantiator.instantiate(PojoInstantiator.java:107)
at org.hibernate.tuple.PojoInstantiator.instantiate(PojoInstantiator.java:123)
at org.hibernate.tuple.entity.AbstractEntityTuplizer.instantiate(AbstractEntityTuplizer.java:366)
at org.hibernate.persister.entity.AbstractEntityPersister.instantiate(AbstractEntityPersister.java:3620)
at org.hibernate.impl.SessionImpl.instantiate(SessionImpl.java:1303)
at org.hibernate.impl.SessionImpl.instantiate(SessionImpl.java:1292)
at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1323)
at org.hibernate.loader.Loader.getRow(Loader.java:1230)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:603)
at org.hibernate.loader.Loader.doQuery(Loader.java:724)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1885)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:71)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:65)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:3062)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:434)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:415)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:165)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:223)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:126)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:906)
at org.hibernate.impl.SessionImpl.internalLoad(SessionImpl.java:874)
at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:590)
at org.hibernate.type.EntityType.resolve(EntityType.java:412)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:139)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:877)
at org.hibernate.loader.Loader.doQuery(Loader.java:752)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.doList(Loader.java:2232)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
at org.hibernate.loader.Loader.list(Loader.java:2124)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
at org.ht.main.EmpTest.main(EmpTest.java:12)

写个简单的例子也报错，还以为映射有问题。

看了下映射文件没有问题，找了下原来是pojo类中没有构造方法或者构造方法有问题

接着加入构造方法就有用了