Question

我有一个包含两个哈希映射的类，并希望加载存储类记录的完整对象。我尝试使用以下代码，但'load'方法给出错误“无法将变量分配给最终变量”

class records{    
    HashMap<String, HashMap<String, Integer> > Map1 = new HashMap <>();
    HashMap<String, HashMap<String, Integer> > Map2 = new HashMap <>();

public boolean store(File f) {
    try {
        FileOutputStream fos = new FileOutputStream(f);
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(this);    // THIS WORKED
        oos.close();
        fos.close();
    } catch (IOException ex) {
        return false;
    }
    return true;
}
public boolean load(File f) {
    try {
        FileInputStream fis = new FileInputStream(f);
        ObjectInputStream ois = new ObjectInputStream(fis);

        this = (records) ois.readObject(); // THIS LINE GIVING ERROR

        ois.close();
        fis.close();
    } catch (IOException e) {
        return false;
    } catch (ClassNotFoundException e) {
        return false;
    }
    return true;

    . . .
}

我是否需要像Load/Store Objects in file in Java一样分别编写和读取两个hashMap元素？

Answer 1

您无法为此分配变量。而是设置单个实例变量或创建新引用。

public records load(File f) {
try {
    FileInputStream fis = new FileInputStream(f);
    ObjectInputStream ois = new ObjectInputStream(fis);

    records r1= (records) ois.readObject(); // THIS LINE GIVING ERROR

    ois.close();
    fis.close();
    return r1;
} catch (IOException e) {
    return null;
} catch (ClassNotFoundException e) {
    return null;
}
return null;

. . .

}

在Java中加载整个（`this`）序列化对象

1 个答案: