使用MiddleGen根据hbm.xml映射文件生成java代码的时候,可能出现如下错误:

BUILD FAILED
D:\Middlegen-Hibernate-r5\build.xml:219: Caused by:
Caused by:
java.lang.NoClassDefFoundError: net/sf/hibernate/MappingException
        at net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.processFile(Hbm2JavaTask.
java:145)
        at net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.execute(Hbm2JavaTask.java
:95)
        at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
        at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:585)
        at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.jav
a:105)
        at org.apache.tools.ant.Task.perform(Task.java:348)
        at org.apache.tools.ant.Target.execute(Target.java:357)
        at org.apache.tools.ant.Target.performTasks(Target.java:385)
        at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1329)
        at org.apache.tools.ant.Project.executeTarget(Project.java:1298)
        at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExe
cutor.java:41)

这主要是因为MiddleGen中导入的Hibernate包和HibernateTools的包版本不一致。目前HibernateTools的版本是2.0的,不支持Hibernate3.0的包。
重新使用Hibernate2的包,再执行一次。问题解决。