• 项目中遇到了一个需要实时读取不重复数据的需求,于是便使用了redis的set类型的数据。

  • demo如下

@RunWith(SpringRunner.class)
@SpringBootTest
public class SetDemo {

    @Autowired
    private StringRedisTemplate redisTemplate;
    
    @Test
    public void demo1() {
        //集合中添加元素,返回添加个数
        redisTemplate.opsForSet().add("games", "鬼泣", "古墓丽影", "仙剑奇侠传", "LOL", "DOTA自走棋");
        printSet("games");
    }
    
    @Test
    public void demo2() {
        //从集合中删除指定元素
        redisTemplate.opsForSet().remove("games", "鬼泣");
        printSet("games");
    }
    
    @Test
    public void demo3() {
        //从集合中随机删除一个元素,并返回该元素
        String item = redisTemplate.opsForSet().pop("games");
        System.out.println(item);
        printSet("games");
    }
    
    @Test
    public void demo4() {
        //将集合1中的指定元素移到集合2
        redisTemplate.opsForSet().move("games", "仙剑奇侠传", "chinese-games");
        //打印集合1
        printSet("games");
        //打印集合2
        printSet("chinese-games");
    }
    
    
    
    @Test
    public void demo5() {
        //获得集合大小
        Long size = redisTemplate.opsForSet().size("games");
        printSet("games");
        System.out.println(size);
    }
    
    @Test
    public void demo6() {
        //判断集合中是否存在某元素
        Boolean ifExist = redisTemplate.opsForSet().isMember("games", "LOL");
        System.out.println(ifExist);
    }
    
    @Test
    public void demo7() {
        //添加集合a
        redisTemplate.opsForSet().add("set-a", "a", "b", "c", "d");
        //添加集合b
        redisTemplate.opsForSet().add("set-b", "a", "b");
        //求交集
        Set<String> intersection = redisTemplate.opsForSet().intersect("set-a", "set-b");
        //也可以和多个key对应的集合求交集                  Set<V> intersect(K key, K otherKey);
        System.out.println(intersection);
    }
    
    @Test
    public void demo8() {
        //添加集合a
        redisTemplate.opsForSet().add("set-a", "a", "b", "c", "d");
        //添加集合b
        redisTemplate.opsForSet().add("set-b", "a", "b");
        //求交集并放入集合c
        redisTemplate.opsForSet().intersectAndStore("set-a", "set-b", "set-c");
        //也可以和多个key对应的集合求交集                 Long intersectAndStore(K key, Collection<K> otherKeys, K destKey);
        //打印集合c
        printSet("set-c");
    }
    
    @Test
    public void demo9() {
        //添加集合m
        redisTemplate.opsForSet().add("set-m", "a", "b", "c", "d");
        //添加集合n
        redisTemplate.opsForSet().add("set-n", "c", "d", "e", "f");
        //求并集
        Set<String> union = redisTemplate.opsForSet().union("set-m", "set-n");
        System.out.println(union);
        
        //其他操作与intersect类似 如和多个key求并集,求并集并放入集合等
    }
    
    @Test
    public void demo10() {
        //添加集合d
        redisTemplate.opsForSet().add("set-d", "a", "b", "c", "d");
        //添加集合e
        redisTemplate.opsForSet().add("set-e", "c", "d", "e", "f");
        //添加集合f
        redisTemplate.opsForSet().add("set-f", "e", "f", "g", "h");
        
        //求差集(属于d不属于e和f)
        Set<String> difference = redisTemplate.opsForSet().difference("set-d", Arrays.asList("set-e", "set-f"));
        System.out.println(difference);
        //其他操作与交集并集类似
    }
    
    @Test
    public void demo11() {
        //随机获取集合中的一个元素
        System.out.println(redisTemplate.opsForSet().randomMember("games"));
        
        //随机获取集合中指定个数的元素(有可能重复)
        System.out.println(redisTemplate.opsForSet().randomMembers("games", 10));
        
        //随机获取集合中指定个数的元素(不重复)
        System.out.println(redisTemplate.opsForSet().distinctRandomMembers("games", 10));

    
    }
    
    /**
     *  打印集合
     * @date 2019年2月12日
     * @author baipengfei
     * @param key
     */
    private void printSet(String key) {
        //获取所有成员
        Set<String> members = redisTemplate.opsForSet().members(key);
        System.out.println(members);
    }
}

Q.E.D.


所以,看不到光,算是不幸吗?需要光才是真正的不幸吧。