------------------------------ Externalizable | ------------------------------ # ¼Ì³ÐÁË:Serializable ½Ó¿Ú # ÌṩÁËÁ©³éÏó·½·¨,Èÿª·¢ÕßʵÏÖÊÖ¶¯µÄÐòÁл¯/·´ÐòÁл¯¶ÔÏó void writeExternal(ObjectOutput out) throws IOException; void readExternal(ObjectInput in) throws IOException, ClassNotFoundException;