Java 对比两个list 找出重复的 和不重复的

使用场景：

list 可以对比两个list 那些是重复的 那些是不重复的，直接把 500 个船名放到list 里面 然后再把 指挥系统查出来的400个船名放到新的list 里面 然后掉一个方法能对比出来两个list 交际 差集 并集

public static List<String> findNonIntersection(List<String> list1, List<String> list2) {
    List<String> difference = new ArrayList<>(list1);
    difference.removeAll(list2);//移除list1里面相同元素 得到差集
    return difference;
}

public static void main(String[] args) {
    List<String> list1 = Arrays.asList("1", "2", "3", "4", "5");
    List<String> list2 = Arrays.asList("1", "2", "4");

    List<String> nonIntersection = findNonIntersection(list1, list2);
    System.out.println("没有交集的部分：" + nonIntersection);
}

实际应用：

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class ShipNameComparison {

    public static void main(String[] args) {
        // 模拟500个船名
        List<String> shipNamesList1 = new ArrayList<>();
        for (int i = 1; i <= 500; i++) {
            shipNamesList1.add("Ship" + i);
        }

        // 模拟400个船名
        List<String> shipNamesList2 = new ArrayList<>();
        for (int i = 250; i <= 650; i++) {
            shipNamesList2.add("Ship" + i);
        }

        // 获取交集、差集和并集
        Set<String> intersection = getIntersection(shipNamesList1, shipNamesList2);
        Set<String> difference1 = getDifference(shipNamesList1, shipNamesList2);
        Set<String> difference2 = getDifference(shipNamesList2, shipNamesList1);
        Set<String> union = getUnion(shipNamesList1, shipNamesList2);

        // 输出结果
        System.out.println("交集: " + intersection);
        System.out.println("船名在List1但不在List2的差集: " + difference1);
        System.out.println("船名在List2但不在List1的差集: " + difference2);
        System.out.println("并集: " + union);
    }
    
    // 获取交集
    public static Set<String> getIntersection(List<String> list1, List<String> list2) {
        Set<String> set1 = new HashSet<>(list1);
        Set<String> set2 = new HashSet<>(list2);
        set1.retainAll(set2); // 保留set1中也存在于set2中的元素
        return set1;
    }

    // 获取差集
    public static Set<String> getDifference(List<String> list1, List<String> list2) {
        Set<String> set1 = new HashSet<>(list1);
        Set<String> set2 = new HashSet<>(list2);
        set1.removeAll(set2); // 移除set1中也存在于set2中的元素
        return set1;
    }

    // 获取并集
    public static Set<String> getUnion(List<String> list1, List<String> list2) {
        Set<String> unionSet = new HashSet<>(list1);
        unionSet.addAll(list2); // 添加list2的所有元素
        return unionSet;
    }
}