1 package cn.fraudmetrix.octopus.horai.biz.utils;
2
3 import java.util.ArrayList;
4 import java.util.Arrays;
5 import java.util.Collections;
6 import java.util.List;
7
8 /**
9 * Created by hunt on 2017/7/31.
10 */
11 @SuppressWarnings("all")
12 public class ListUtil {
13 /**
14 * 求ls对ls2的差集,即ls中有，但ls2中没有的
15 *
16 * @param ls
17 * @param ls2
18 * @return
19 */
20 public static List diff(List ls, List ls2) {
21 List list = new ArrayList(Arrays.asList(new Object[ls.size()]));
22 Collections.copy(list, ls);
23 list.removeAll(ls2);
24 return list;
25 }
26
27 /**
28 * 求2个集合的交集
29 *
30 * @param ls
31 * @param ls2
32 * @return
33 */
34 public static List intersect(List ls, List ls2) {
35 List list = new ArrayList(Arrays.asList(new Object[ls.size()]));
36 Collections.copy(list, ls);
37 list.retainAll(ls2);
38 return list;
39 }
40
41 /**
42 * 求2个集合的并集
43 *
44 * @param ls
45 * @param ls2
46 * @return
47 */
48 public static List union(List ls, List ls2) {
49 List list = new ArrayList(Arrays.asList(new Object[ls.size()]));
50 Collections.copy(list, ls);//将ls的值拷贝一份到list中
51 list.removeAll(ls2);
52 list.addAll(ls2);
53 return list;
54 }
55 }
