DbUnit is a JUnit extension (also usable with Ant) targeted at database-driven projects that, among other things, puts your database into a known state between test runs. This is an excellent way to avoid the myriad of problems that can occur when one test case corrupts the database and causes subsequent tests to fail or exacerbate the damage.
DbUnit has the ability to export and import your database data to and from XML datasets. Since version 2.0, DbUnit can also work with very large datasets when used in streaming mode. DbUnit can also help you to verify that your database data match an expected set of values.
dbunit是一个基于junit扩展的数据库测试框架。它提供了大量的类对与数据库相关的操作进行了抽象和封装，虽然在80%的情况，你只需使用它极少的api。它通过使用用户自定义的数据集以及相关操作使数据库处于一种可知的状态，从而使得测试自动化、可重复和相对独立。
dbunit的原理
dbunit的与单元测试相关的两个最重要的核心是org.dbunit.database.IDatabaseConnection 和 org.dbunit.dataset.IDataSet ，前者(IDatabaseConnection)是产品代码使用的数据库连接的一个简单的封装，后者(.IDataSet )是对单元测试人员自定义的数据集（通常以xml文件的形式存在，且xml文件的格式也有好几种）的封装。
还有一个很重要的就是org.dbunit.operation.DatabaseOperation，该类是一个抽象类代表了对数据库的操作，例如CUD以及其组合等， 它采用了退化的工厂模式，可直接通过它获取其具体的子类