java如何在POJO类中使用HashMap并检索它？

Question

在我的POJO中，我应该在哪里写hashmap

我试过我的构造函数，我不知道如何使用hashmap？ 尤其是在我的POJO课程中-->

public class CurrentAttendance {

    private String name;
    private int userCount;
    private int currentAttendance;
    private long firstJoin;
    private Object timestamp;

    //empty constructor
    public CurrentAttendance() {
    }

    //entry values
    public CurrentAttendance(String name, int userCount, int currentAttendance, long firstJoin, Object timestamp) {
        this.name = name;
        this.userCount = userCount;
        this.currentAttendance = currentAttendance;
        this.firstJoin = firstJoin;
        this.timestamp = timestamp;
    }

这是我的救命稻草

    public String getXName(){
        return name;
    }
    public int getUserCount(){
        return userCount;
    }
    public int getCurrentAttendance() {
        return currentAttendance;
    }
    public long getFirstJoin(){
        return firstJoin;
    }
    public Object getTimestamp(){
        return timestamp;
    }
}

Answer 1

你的问题令人困惑

是否要拥有HashMap私有数据成员？您始终可以这样做：

public class CurrentAttendance {
    private Map something = new HashMap();

    public Map getSomething() { return Collections.unmodifiableMap(this.something); }
}