对象的写入与读取。将一个类的对象(例如：Calendar)写入到文件，然后顺序读出该对象，并验证读出的对象是否原始对象的克隆。-Object written and read. A class of objects (for example: Calendar) written to the file, then read out the order of the object, and verify whether the object is read out a clone of the original object.