如何写一个HashMap到一个txt文件？

问题描述

我有一个包含一些数据，我想写到文件并重新加载文件的内容，形成相同的HashMap的HashMap中。

I have a HashMap containing some data that I want to write to a file and reload the contents of the file to form the same HashMap.

HashMap中如下所示：

HashMap is as follows:

    HashMap<Long, List<DataPoint>> hashMap = new HashMap<Long, List<DataPoint>>();

和数据点类如下：

public class DataPoint {

private int time;
private int songId;

public DataPoint(int songId, int time) {
    this.songId = songId;
    this.time = time;
}

public int getTime() {
    return time;
}

public int getSongId() {
    return songId;
}
 }

帮助是非常AP preciated。

Help is much appreciated.

感谢

推荐答案

更改数据点来实现java.io.Serializable和使用ObjectOutputStream.writeObject / ObjectInputStream.readObject。所有的Java SE集合实现序列化

Change DataPoint to implement java.io.Serializable and use ObjectOutputStream.writeObject / ObjectInputStream.readObject. All Java SE collection implementations are Serializable

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