提供一个方便的Java 的toString 方法，以后所有的实体bean不需要再书写toString 方法了。 通过反射机制获取实体内部的数据，以及引用的书据。-Provides a convenient method of Java' s toString, after all of the entity bean does not require re-writing toString methods. Through the reflection mechanism for entities within the data, and reference books, according to.