java - 无法序列化 Hashmap，java.io.NotSerializedException

Question

public class Common implements Serializable{

    private static HashMap<Integer,List<LevelList>> levelListMap = new HashMap<>();

    public static Map<Integer, List<LevelList>> getLevelListMap(Context context) {

        File file = new File(context.getDir("data", MODE_PRIVATE), "map");
        ObjectInputStream inputStream = null;
        try {
            inputStream = new ObjectInputStream(new FileInputStream(file));
            levelListMap = (HashMap<Integer, List<LevelList>>) inputStream.readObject();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return levelListMap;
    } ...
}

我无法序列化 hashmap。我不断收到 java.io.NotSerializableException为了 levelListMap = (HashMap<Integer, List<LevelList>>) inputStream.readObject();

public class LevelList implements Serializable{

    public int id;
    public String title;
    public String imgurl;
    public String songurl;
    public String songtext;
    boolean isFavourite;

    public void release() {

    }


    public void setFavourite(boolean favourite) {
        isFavourite = favourite;
    }

    public boolean isFavourite(){
        return isFavourite;
    }

}

Answer 1

HashMap是可序列化的，但键和值也必须是可序列化的。确保所有键和值都是可序列化的，并且它们的字段也是可序列化的(不包括 transient 和静态成员)。

编辑:

HashMap<Integer,List<LevelList>> ，是你的List实现可序列化？