错误报告：八月 12, 2016 6:12:21 下午 org.hibernate.annotations.common.Version <clinit>INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final}八月 12, 2016 6:12:21 下午 org.hibernate.Version logVersionINFO: HHH000412: Hibernate Core {4.1.12.Final}八月 12, 2016 6:12:21 下午 org.hibernate.cfg.Environment <clinit>INFO: HHH000206: hibernate.properties not found八月 12, 2016 6:12:21 下午 org.hibernate.cfg.Environment buildBytecodeProviderINFO: HHH000021: Bytecode provider name : javassist八月 12, 2016 6:12:21 下午 org.hibernate.cfg.Configuration configureINFO: HHH000043: Configuring from resource: /hibernate.cfg.xml八月 12, 2016 6:12:21 下午 org.hibernate.cfg.Configuration getConfigurationInputStreamINFO: HHH000040: Configuration resource: /hibernate.cfg.xml八月 12, 2016 6:12:21 下午 org.hibernate.internal.util.xml.DTDEntityResolver resolveEntityWARN: HHH000223: Recognized obsolete hibernate namespace http://hibernate.sourceforge.net/. Use namespace http://www.hibernate.org/dtd/ instead. Refer to Hibernate 3.6 Migration Guide!八月 12, 2016 6:12:21 下午 org.hibernate.cfg.Configuration addResourceINFO: HHH000221: Reading mappings from resource: framework01/Students.hbm.xml八月 12, 2016 6:12:21 下午 org.hibernate.internal.util.xml.DTDEntityResolver resolveEntityWARN: HHH000223: Recognized obsolete hibernate namespace http://hibernate.sourceforge.net/. Use namespace http://www.hibernate.org/dtd/ instead. Refer to Hibernate 3.6 Migration Guide!八月 12, 2016 6:12:21 下午 org.hibernate.cfg.Configuration doConfigureINFO: HHH000041: Configured SessionFactory: null Configured SessionFactory: null为空的具体表象·····？