Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]解决办法！！！

org.hibernate.MappingException: Could not get constructor for org.hibernate.persister.entity.SingleTableEntityPersister
    at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:185)
    at org.hibernate.persister.internal.PersisterFactoryImpl.createEntityPersister(PersisterFactoryImpl.java:135)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:401)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1857)
    at com.fkr.po.HibernateSessionFactory.<clinit>(HibernateSessionFactory.java:34)
    at com.fkr.dao.UserDAO.add(UserDAO.java:14)
    at com.fkr.dao.UserDAO.main(UserDAO.java:11)
Caused by: org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]
    at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:138)
    at org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:188)
    at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:403)
    at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:520)
    at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:148)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:163)
    ... 6 more
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:135)
    ... 15 more
Caused by: java.lang.NoClassDefFoundError: javassist/util/proxy/MethodFilter
    at org.hibernate.bytecode.internal.javassist.BytecodeProviderImpl.getProxyFactoryFactory(BytecodeProviderImpl.java:58)
    at org.hibernate.tuple.entity.PojoEntityTuplizer.buildProxyFactoryInternal(PojoEntityTuplizer.java:244)
    at org.hibernate.tuple.entity.PojoEntityTuplizer.buildProxyFactory(PojoEntityTuplizer.java:222)
    at org.hibernate.tuple.entity.AbstractEntityTuplizer.<init>(AbstractEntityTuplizer.java:212)
    at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:80)
    ... 20 more
Caused by: java.lang.ClassNotFoundException: javassist.util.proxy.MethodFilter
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    ... 25 more
二月 14, 2017 6:23:06 下午 org.hibernate.cfg.Configuration configure
INFO: HHH000043: Configuring from resource: /hibernate.cfg.xml
二月 14, 2017 6:23:06 下午 org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: HHH000040: Configuration resource: /hibernate.cfg.xml
二月 14, 2017 6:23:06 下午 org.hibernate.cfg.Configuration addResource
INFO: HHH000221: Reading mappings from resource: com/fkr/po/User.hbm.xml
二月 14, 2017 6:23:06 下午 org.hibernate.cfg.Configuration doConfigure
INFO: HHH000041: Configured SessionFactory: null
二月 14, 2017 6:23:06 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH000402: Using Hibernate built-in connection pool (not for production use!)
二月 14, 2017 6:23:06 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://127.0.0.1/h2?useUnicode=true&characterEncoding=UTF-8]
二月 14, 2017 6:23:06 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH000046: Connection properties: {user=root, password=****}
二月 14, 2017 6:23:06 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH000006: Autocommit mode: false
二月 14, 2017 6:23:06 下午 org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
二月 14, 2017 6:23:06 下午 org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
二月 14, 2017 6:23:06 下午 org.hibernate.cfg.Configuration$MappingsImpl addImport
INFO: HHH000071: Duplicate import: com.fkr.po.User -> com.fkr.po.User
二月 14, 2017 6:23:06 下午 org.hibernate.cfg.Configuration$MappingsImpl addImport
INFO: HHH000071: Duplicate import: com.fkr.po.User -> User
%%%% Error Creating SessionFactory %%%%
org.hibernate.InvalidMappingException: Could not parse mapping document from resource com/fkr/po/User.hbm.xml
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processHbmXml(Configuration.java:3762)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processHbmXmlQueue(Configuration.java:3751)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3739)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1410)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1844)
    at com.fkr.po.HibernateSessionFactory.rebuildSessionFactory(HibernateSessionFactory.java:73)
    at com.fkr.po.HibernateSessionFactory.getSession(HibernateSessionFactory.java:55)
    at com.fkr.dao.UserDAO.add(UserDAO.java:14)
    at com.fkr.dao.UserDAO.main(UserDAO.java:11)
Caused by: org.hibernate.DuplicateMappingException: Duplicate class/entity mapping com.fkr.po.User
    at org.hibernate.cfg.Configuration$MappingsImpl.addClass(Configuration.java:2835)
    at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:178)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processHbmXml(Configuration.java:3759)
    ... 8 more
Exception in thread "main" java.lang.NullPointerException
    at com.fkr.dao.UserDAO.add(UserDAO.java:27)
    at com.fkr.dao.UserDAO.main(UserDAO.java:11)

以上是错误信息，修改方法如下；

　　在你的项目的pom.xml中 <dependencies></dependencies>标签后面添加下面的配置信息内容即可解决上面的错误。

　　

<repositories>
        <repository>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
            <id>maven</id>
            <name>Maven Repository Switchboard</name>
            <url>http://repo1.maven.org/maven2</url>
        </repository>

    </repositories>
    <build>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.2</version>
                <configuration>
                    <version>3.0</version>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>