java 集合(3) set 接口/ set 常用算法

set 接口/ set 常用算法public static void main(String[] args)  {//System.out.println(iplong.int2ipv4((long) 714902304));Set set = new HashSet();//Set基于父接口collection 没加什么新方法，规定其中元素无序，不重复set.add("hello");set.add("hello");set.add(new Iplong("li","jia"));set.add(new Iplong("li","ji"));set.add(new Iplong("lia","jia"));set.add(new Iplong("lia","jia"));//这个重复的加不进去，因为重写了equals()方法System.out.println(set.toString());//交集，并集Set s1 = new HashSet(); Set s2 = new HashSet();s1.add("a");s1.add("b");s1.add("c");s2.add("a");s2.add("b");s2.add("d");Set sjiao = new HashSet(s1);Set sbing = new HashSet(s1);sjiao.retainAll(s2);//交集sbing.addAll(s2);//并集System.out.println(sjiao+"\t"+sbing);}结果：[liji, lijia, hello, liajia][b, a][d, b, c, a]