关于Hibernate的一个错误 Identifier text cannot be null

2018-03-26 05:20:21 1.3k 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

Hibernate实战：MySQL到Oracle数据迁移的踩坑与性能优化数据迁移是后端开发中绕不开的高难度任务，尤其在跨数据库平台时，需要处理字段映射、主键策略、时区差异以及大数据量下的内存与性能问题。ORM框架Hibernate通过对象模型与数据库方言的映射，能够在复杂业务系统中复用已有实体关系，显著降低手工SQL的翻译成本。当源库为MySQL、目标库为Oracle时，利用Hibernate的分页读取、批量写入、事务边界控制以及连接池调优，可以有效规避OOM、主键冲突和LazyInitializationException等典型故障。本文从实体映射、双数据源配置、键集分页、断阅读详情

1.hibernate配置如下 :



<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE hibernate-configuration PUBLIC

	"-//Hibernate/Hibernate Configuration DTD 3.0//EN"

	"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

	<session-factory>

	

		<!-- 

		#hibernate.dialect org.hibernate.dialect.MySQLDialect

		#hibernate.dialect org.hibernate.dialect.MySQLInnoDBDialect

		#hibernate.dialect org.hibernate.dialect.MySQLMyISAMDialect

		#hibernate.connection.driver_class com.mysql.jdbc.Driver

		#hibernate.connection.url jdbc:mysql:///test

		#hibernate.connection.username gavin

		#hibernate.connection.password

		 -->

		 <!-- 数据库驱动 -->

		<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>

		 <!-- 数据库url -->

		<property name="hibernate.connection.url">jdbc:mysql:///projectone</property>

		 <!-- 数据库连接用户名 -->

		<property name="hibernate.connection.username">root</property>

		 <!-- 数据库连接密码 -->

		<property name="hibernate.connection.password">root</property>

		<!-- 数据库方言

			不同的数据库中,sql语法略有区别. 指定方言可以让hibernate框架在生成sql语句时.针对数据库的方言生成.

			sql99标准: DDL 定义语言  库表的增删改查

					  DCL 控制语言  事务 权限

					  DML 操纵语言  增删改查

			注意: MYSQL在选择方言时,请选择最短的方言.

		 -->

		<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

		

		

		<!-- #hibernate.show_sql true 

			 #hibernate.format_sql true

		-->

		<!-- 将hibernate生成的sql语句打印到控制台 -->

		<property name="hibernate.show_sql">true</property>

		<!-- 将hibernate生成的sql语句格式化(语法缩进) -->

		<property name="hibernate.format_sql">true</property>

		<!-- 

		## auto schema export  自动导出表结构. 自动建表

		#hibernate.hbm2ddl.auto create		自动建表.每次框架运行都会创建新的表.以前表将会被覆盖,表数据会丢失.(开发环境中测试使用)

		#hibernate.hbm2ddl.auto create-drop 自动建表.每次框架运行结束都会将所有表删除.(开发环境中测试使用)

		#hibernate.hbm2ddl.auto update(推荐使用) 自动生成表.如果已经存在不会再生成.如果表有变动.自动更新表(不会删除任何数据).

		#hibernate.hbm2ddl.auto validate	校验.不自动生成表.每次启动会校验数据库中表是否正确.校验失败.

		 -->

		<property name="hibernate.hbm2ddl.auto">update</property>

		<!-- 引入orm元数据

			路径书写: 填写src下的路径

		 -->

		<mapping resource="club/dohacker/entity/Course.hbm.xml" />

		<mapping resource="club/dohacker/entity/FileInfo.hbm.xml" />

		<mapping resource="club/dohacker/entity/Student.hbm.xml" />

		<mapping resource="club/dohacker/entity/Teacher.hbm.xml" />

		<mapping resource="club/dohacker/entity/Department.hbm.xml" />

		<mapping resource="club/dohacker/entity/StudentCourseInfo.hbm.xml" />

		<mapping resource="club/dohacker/entity/Class.hbm.xml" />

	</session-factory>

</hibernate-configuration>

2.HibernateUtils类如下:



public class HibernateUtils {

	private static SessionFactory sf;

	

	static{

		Configuration conf = new Configuration().configure();

		sf = conf.buildSessionFactory();

	}

	

	public static Session openSession(){

				Session session = sf.openSession();

				return session;

	}

	

	public static Session getCurrentSession(){

		Session session = sf.getCurrentSession();

		

		return session;

	}

	public static void main(String[] args) {

		System.out.println(HibernateUtils.openSession());

	}

	

}

问题是每当走到 sf = conf.buildSessionFactory(); 这一行代码的时候就发生错误了 , 我重新建立了orm文件 , 之前没有发生过错误 , 重写了orm文件后多就发生了这种错误 , 望高人指点一下，百度也没有找到原因 :



org.hibernate.boot.model.naming.IllegalIdentifierException: Identifier text cannot be null

	at org.hibernate.boot.model.naming.Identifier.<init>(Identifier.java:107)

	at org.hibernate.boot.model.naming.Identifier.toIdentifier(Identifier.java:46)

	at org.hibernate.engine.jdbc.env.internal.NormalizingIdentifierHelperImpl.toIdentifier(NormalizingIdentifierHelperImpl.java:83)

	at org.hibernate.boot.model.relational.Database.toIdentifier(Database.java:104)

	at org.hibernate.boot.model.source.internal.hbm.RelationalObjectBinder.bindColumn(RelationalObjectBinder.java:116)

	at org.hibernate.boot.model.source.internal.hbm.RelationalObjectBinder.bindColumnsAndFormulas(RelationalObjectBinder.java:87)

	at org.hibernate.boot.model.source.internal.hbm.ModelBinder$AbstractPluralAttributeSecondPass.bindCollectionKey(ModelBinder.java:3277)

	at org.hibernate.boot.model.source.internal.hbm.ModelBinder$AbstractPluralAttributeSecondPass.doSecondPass(ModelBinder.java:3078)

	at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1655)

	at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1623)

	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278)

	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)

	at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)

	at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)

	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:692)

	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)

	at club.dohacker.utils.HibernateUtils.<clinit>(HibernateUtils.java:14)

	at club.dohacker.filter.SessionFilter.doFilter(SessionFilter.java:34)

	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)

	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)

	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)

	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)

	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)

	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)

	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)

	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563)

	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)

	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:399)

	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:317)

	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:204)

	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:182)

	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:311)

	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

	at java.lang.Thread.run(Unknown Source)