Question

有两个级别的玩家和游戏。实现序列化和文件。序列化工作正常。无法获得对象数组的最大长度。我想要数组中没有对象。

class player {
  private String username;
}

class game {
  player array[] = new player[100];
  int arraysize;
  player player;

  public void setArraySize(int arraySize) {
    this.arraySize = arraySize;
  }

  public void readdata() { // reading from file starts
    //ObjectInputStream input = null;
    try {
      ObjectInputStream input = new ObjectInputStream(new FileInputStream("myfile.txt"));
      array = (NimPlayer[]) input.readObject();

    } catch (Exception e) {
      e.printStackTrace();
    }
    initializearraylength(array);
  }// reading file ends

  public void initializearraylength(NimPlayer[] temparray) {
    int size = temparray.length;
    setArraySize(size);
    System.out.println(size); // output displays size 100
  }
}
public display() {
  for (int i = 0; i < arraysize; i++) {
    System.out.println(array[i].getusername());
  }
}

变量arraySize没有初始化。我尝试了这段代码并在try的readdata（）firstline中得到一个空指针异常。

java.io.EOFException
    at java.io.ObjectInputStream$PeekInputStream.readFully(Unknown Source)
    at java.io.ObjectInputStream$BlockDataInputStream.readShort(Unknown Source)
    at java.io.ObjectInputStream.readStreamHeader(Unknown Source)
    at java.io.ObjectInputStream.<init>(Unknown Source)
    at game.readdata(game.java:507)

Answer 1

你的档案是空的。

我不知道为什么你甚至有一个arraySize变量，如果它始终与array.length.相同，只需删除它即可。如果你保留它，你肯定不需要两种方法来设置它。

Answer 2

对象数量

  List<NimPlayer> tmp = Arrays.asList((NimPlayer[]) input.readObject());
  System.out.println(tmp.size());

对于错误，将声明的变量int arraysize更改为arraySize

反序列化后如何初始化我的对象数组

2 个答案: