redis数据类型-集合类型SADD: 向集合中添加元素：
192.168.2.120:6379> SADD jihe1 a b c
(integer) 3
192.168.2.120:6379> SADD jihe2 b c d
(integer) 3
查看集合的成员：
192.168.2.120:6379> SMEMBERS jihe1
1) "b"
2) "a"
3) "c"
192.168.2.120:6379> SMEMBERS jihe2
1) "b"
2) "d"
3) "c"
判断集合元素是否存在：
192.168.2.120:6379> SISMEMBER jihe1 a #判断a 是否在集合jihe1中,在返回1，不在返回0
(integer) 1
192.168.2.120:6379> SISMEMBER jihe1 f
(integer) 0
集合的运算：
集合的差集SDIFF：
192.168.2.120:6379> SMEMBERS jihe1
1) "b"
2) "a"
3) "c"
192.168.2.120:6379> SMEMBERS jihe2
1) "b"
2) "d"
3) "c"
192.168.2.120:6379> SDIFF jihe1 jihe2
1) "a"
192.168.2.120:6379> SDIFF jihe2 jihe1
1) "d"
集合交集SINTER:
192.168.2.120:6379> SMEMBERS jihe1
1) "b"
2) "a"
3) "c"
192.168.2.120:6379> SMEMBERS jihe2
1) "b"
2) "d"
3) "c"
192.168.2.120:6379> SINTER jihe1 jihe2
1) "b"
2) "c"
集合并集SUNION:
192.168.2.120:6379> SMEMBERS jihe1
1) "b"
2) "a"
3) "c"
192.168.2.120:6379> SMEMBERS jihe2
1) "b"
2) "d"
3) "c"
192.168.2.120:6379> SUNION jihe1 jihe2
1) "a"
2) "b"
3) "d"
4) "c"
