集合1 2 3 4 和集合3 4 5 6求两集合的并集，交集和差集，用java语音

下面是用 Java 语言实现求两个集合的并集、交集和差集的代码：

import java.util.*;

public class SetOperations {
    public static void main(String[] args) {
        Set<Integer> set1 = new HashSet<>(Arrays.asList(1, 2, 3, 4));
        Set<Integer> set2 = new HashSet<>(Arrays.asList(3, 4, 5, 6));

        // 求并集
        Set<Integer> union = new HashSet<>(set1);
        union.addAll(set2);
        System.out.println("Set union: " + union);

        // 求交集
        Set<Integer> intersection = new HashSet<>(set1);
        intersection.retainAll(set2);
        System.out.println("Set intersection: " + intersection);

        // 求差集
        Set<Integer> difference1 = new HashSet<>(set1);
        difference1.removeAll(set2);
        System.out.println("Set difference (set1 - set2): " + difference1);

        Set<Integer> difference2 = new HashSet<>(set2);
        difference2.removeAll(set1);
        System.out.println("Set difference (set2 - set1): " + difference2);
    }
}

输出结果为：

Set union: [1, 2, 3, 4, 5, 6]
Set intersection: [3, 4]
Set difference (set1 - set2): [1, 2]
Set difference (set2 - set1): [5, 6]