下载了Hibernate3.1编译，无论通过build.bat还是ant jar都会出错。前者会说找不到javac，我晕倒。后者说antlr/Tool找不到。
后来在hibernate网站上(http://www.hibernate.org/6.html)看到：
Fixing Ant classpath/plugin issues
You may need to add junit.jar to your $ANT_HOME/lib directory if it is not there already, or alternatively remove the $ANT_HOME/lib/ant-junit.jar file. For Hibernate3, repeat the steps above, but also copy lib/antlr.jar or remove the $ANT_HOME/lib/ant-antlr.jar file.
These
steps are necessary because Ant ships with plugin stub libraries in its
classpath, so Ant plugins for JUnit or Antlr can't be used without
copying or removing files. If you don't have Ant installed on your
machine or don't want to mess with the default Ant installation then,
on Windows, just run build.bat to use the bundled Ant libraries.
虽然他说可以用build.bat来进行，但我也不知道他为什么会找不到javac，反正我把antlr.jar拷到ant的lib下面，就OK了。