java反序列化时得到的对象有问题

public class Recorder {
    private static Vector<EnemyTank> enemyTanks = null;
    public  static String recordFilePath = "e:\\mytemp\\recordenemy.dat";
    private static int allEnemyNum = 0;
    private static ObjectOutputStream oos = null;
    public  static String recordFile = "e:\\mytemp\\record.txt";
    private static BufferedWriter bw = null;
    private static ObjectInputStream ois = null;
    private static BufferedReader br = null;

//得到击毁敌人坦克成绩数
    public static void getEnemyNum(){
        try {
            br = new BufferedReader(new FileReader(recordFile));
            allEnemyNum = Integer.parseInt(br.readLine());
//            Recorder.setAllEnemyNum(allEnemyNum);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(br != null){
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
//得到记录了坐标及方向的敌人坦克
public static Vector<EnemyTank> readEnemy(){
        Vector<EnemyTank> enemyTanks = new Vector<>();


    try {
        FileInputStream fis = new FileInputStream(recordFilePath);
        ois = new ObjectInputStream(fis);
           while(fis.available() > 0){
//               System.out.println((EnemyTank) ois.readObject());
               EnemyTank enemyTank = (EnemyTank) ois.readObject();
               enemyTanks.add(enemyTank);
               System.out.println(enemyTank);
           }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {

        if(ois != null){
            try {
                ois.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    return enemyTanks;
}
   
   //记录击毁敌人坦克成绩数
    public static void saveRecord(){
        try {
            bw = new BufferedWriter(new FileWriter(recordFile));
            bw.write(getAllEnemyNum() + "\r\n");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(bw != null){
                try {
                    bw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }
    public static void addAllEnemyNum(){
        allEnemyNum++;
    }

    public static int getAllEnemyNum() {
        return allEnemyNum;
    }

    public static void setAllEnemyNum(int allEnemyNum) {
        Recorder.allEnemyNum = allEnemyNum;
    }

    //记录关闭时剩余敌人坦克的坐标及方向
    public static void saveEnemy()    {

    try {
            oos = new ObjectOutputStream(new FileOutputStream(recordFilePath));
//            EnemyTank enemyTank = new EnemyTank(200,500,0);
//            oos.writeObject(enemyTank);
        for (int i = 0; i < enemyTanks.size(); i++) {
            EnemyTank enemyTank = enemyTanks.get(i);
            if(enemyTank.isIslive()){
                EnemyTank saveEnemy = new EnemyTank(enemyTank.getX(),enemyTank.getY(),
                        enemyTank.getDirection());
                oos.writeObject(saveEnemy);
                System.out.println(saveEnemy);
            }
        }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
        if(oos != null){
            try {
                oos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    }

    public static void setEnemyTanks(Vector<EnemyTank> enemyTanks) {
        Recorder.enemyTanks = enemyTanks;
    }

}

以上通过结束时敌人坦克的x,y坐标和方向 new的对线传给dat文件，但是反序列化读取的时候得到的对象x,y,和方向三个int类型的值都变成了0，导致读取的敌人坦克都是出现在原点，是哪里出了问题呀 求帮忙看下