Java - 如何创建新条目(键、值)

问题描述：

我想创建类似于 Util.Map.Entry 的新项目，它将包含结构 key, value.

I'd like to create new item that similarly to Util.Map.Entry that will contain the structure key, value.

问题是我无法实例化 Map.Entry 因为它是一个接口.

The problem is that I can't instantiate a Map.Entry because it's an interface.

有谁知道如何为 Map.Entry 创建一个新的通用键/值对象?

Does anyone know how to create a new generic key/value object for Map.Entry?

答

你可以自己实现 Map.Entry 接口:

You can just implement the Map.Entry<K, V> interface yourself:

import java.util.Map;

final class MyEntry<K, V> implements Map.Entry<K, V> {
    private final K key;
    private V value;

    public MyEntry(K key, V value) {
        this.key = key;
        this.value = value;
    }

    @Override
    public K getKey() {
        return key;
    }

    @Override
    public V getValue() {
        return value;
    }

    @Override
    public V setValue(V value) {
        V old = this.value;
        this.value = value;
        return old;
    }
}

然后使用它:

Map.Entry<String, Object> entry = new MyEntry<String, Object>("Hello", 123);
System.out.println(entry.getKey());
System.out.println(entry.getValue());

Java - 如何创建新条目(键、值)

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