问题1 hibernate.cfg.xml配置文件
<?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> <!-- Database connection settings --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=UTF-8</property> <property name="connection.username">root</property> <property name="connection.password">123456</property> <!-- JDBC connection pool (use the built-in) --> <property name="connection.pool_size">1</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <!-- Echo all executed SQL to stdout --> <property name="show_sql">true</property> <!-- Drop and re-create the database schema on startup --> <property name="hbm2ddl.auto">none</property> <mapping class="/testhibernate/src/org/hibernate/Student"/> <!-- 配置Student类名的路径 --> </session-factory> </hibernate-configuration>出错信息：
Exception in thread "main" org.hibernate.MappingException: Unable to load class [ /testhibernate/src/org/hibernate/Student] declared in Hibernate configuration <mapping/> entry at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:2221) at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:2169) at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:2149) at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:2102) at org.hibernate.cfg.Configuration.configure(Configuration.java:2017) at org.hibernate.Main.main(Main.java:14) Caused by: java.lang.ClassNotFoundException: /testhibernate/src/org/hibernate/Student at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at org.hibernate.internal.util.ReflectHelper.classForName(ReflectHelper.java:192) at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:2218) ... 5 more解决方案：
1.hibernate.cfg.xml放在src目录下
2.<mapping class="/testhibernate/src/org/hibernate/Student"/> 类文件写错，不能用"/",应该用" . " <mapping class="org.hibernate.Student" />
这个问题解决之后出现了另一个问题：加载数据库驱动时出错
问题2
Exception in thread "main" org.hibernate.service.classloading.spi.ClassLoadingException: Specified JDBC Driver com.mysql.jdbc.Driver could not be loaded at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:111) at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:85) at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:184) at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:156) at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.buildJdbcConnectionAccess(JdbcServicesImpl.java:223) at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:89) at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:85) at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:184) at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:156) at org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1827) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1785) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1870) at org.hibernate.Main.main(Main.java:16) Caused by: org.hibernate.service.classloading.spi.ClassLoadingException: Unable to load class [com.mysql.jdbc.Driver] at org.hibernate.service.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:151) at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:106) ... 12 more Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver at org.hibernate.service.classloading.internal.ClassLoaderServiceImpl$AggregatedClassLoader.findClass(ClassLoaderServiceImpl.java:318) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at org.hibernate.service.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:148) ... 13 more 解决方案：忘记导入连接数据库的jar包了，导入之后就ok了mysql-connector-java-5.1.6.jar
