public class ObjectToByteDemo {
	
	  public static void main(String[] args){
		  try {
			ObjectOutputStream objectWriter =new ObjectOutputStream(
			new FileOutputStream("testFolder/objectTestDemo.txt"));
			StudentDemo st =new StudentDemo("XiaoMing","45398",19);
			StudentDemo st01 =new StudentDemo("Chen","87659",22);
			
			objectWriter.writeObject(st);
			objectWriter.writeObject(st01);
			objectWriter.flush();
			objectWriter.close();
			
			ObjectInputStream objectReader = new ObjectInputStream( 
			new FileInputStream("testFolder/objectTestDemo.txt"));
			StudentDemo tmpStu =(StudentDemo)objectReader.readObject();
			System.out.println(tmpStu);
			//Return the object read from the stream
			StudentDemo tmpStu01 =(StudentDemo)objectReader.readObject();
			System.out.println(tmpStu01);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		  
		  
	  }

}

结果：

StudentDemo [stuName=XiaoMing, stuID=45398, age=19]
StudentDemo [stuName=Chen, stuID=87659, age=22]

不会被覆盖，可以理解为像read()方法一样，指针从0开始，偏移一个读一个对象出来。

不能指定反序列哪一个对象。