public class PairTest {
    public static void main(String[] args) {
        System.out.println("========== Pair<K,V> 测试 ==========");

        Pair<String, Integer> pair1 = new Pair<>("apple", 1);
        System.out.println("原始 Pair: " + pair1);

        Pair<Integer, String> swappedPair = pair1.swap();
        System.out.println("交换后 Pair: " + swappedPair);

        Pair<Double, String> pair2 = new Pair<>(3.14, "PI");
        System.out.println("原始 Pair: " + pair2);

        Pair<String, Double> swappedPair2 = pair2.swap();
        System.out.println("交换后 Pair: " + swappedPair2);

        System.out.println("\n交换方法的键值类型: " +
            "Pair<Double,String> -> Pair<String,Double> 成功!");
    }
}