基于RedisTemplate中的 set 的交，差，并集

迈不过友情╰ 2022-12-09 05:18 404阅读 0赞

## 1.set类型常用方法 ##

*  添加元素：redisTemplate.opsForSet().add(key, values)
 *  移除元素(单个值、多个值)：redisTemplate.opsForSet().remove(key, values)
 *  删除并且返回一个随机的元素：redisTemplate.opsForSet().pop(key)
 *  获取集合的大小：redisTemplate.opsForSet().size(key)
 *  判断集合是否包含value：redisTemplate.opsForSet().isMember(key, value)
 *  获取两个或更多集合的交集：redisTemplate.opsForSet().intersect(key, otherKey)
 *  key集合与otherKey集合的交集存储到destKey集合中：redisTemplate.opsForSet().intersectAndStore(key, otherKey, destKey)
 *  获取两个或者多个集合的并集：redisTemplate.opsForSet().union(key, otherKeys)
 *  key集合与otherKey集合的并集存储到destKey中：redisTemplate.opsForSet().unionAndStore(key, otherKey, destKey)
 *  随机获取集合中的一个元素：redisTemplate.opsForSet().randomMember(key)
 *  获取集合中的所有元素：redisTemplate.opsForSet().members(key)
 *  随机获取集合中count个元素：redisTemplate.opsForSet().randomMembers(key, count)
 *  获取多个key无序集合中的元素（去重），count表示个数：redisTemplate.opsForSet().distinctRandomMembers(key, count)
 *  遍历set类似于Interator：redisTemplate.opsForSet().scan(key, options)

## 2.交，差，并集的测试 ##

package com.example.demo;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.data.redis.core.RedisTemplate;
    import org.springframework.data.redis.core.SetOperations;
    import org.springframework.test.context.junit4.SpringRunner;
    
    import java.util.Arrays;
    import java.util.Set;
    
    @RunWith(SpringRunner.class)
    @SpringBootTest
    public class demo01 { 
    
        @Autowired
        private RedisTemplate redisTemplate;
    
        @Test
        public void test01(){ 
            SetOperations set = redisTemplate.opsForSet();
    
            set.add("zd","1","2","3");
            set.add("bg","1","2","3","4","5");
    
            //差集，获取“bg”键有，而“zd”键没有的元素
            Set difference = set.difference("bg", "zd");
            System.out.println(difference);//[4,5]
    
            //交集,获取“bg”键和“zd”键两个键的共有元素
            Set intersect = set.intersect("bg", "zd");
            System.out.println(intersect);//[3, 2, 1]
    
            //并集，获取“bg”键和“zd”键两个键下的所有元素，排除重合元素
            Set union = set.union("bg", "zd");
            System.out.println(union);//[4, 3, 5, 1, 2]
    
    
        }
    
        @Test
        public void test02() { 
            SetOperations set = redisTemplate.opsForSet();
            
            //添加集合d
            set.add("set-d", "a", "b", "c", "d");
            //添加集合e
            set.add("set-e", "c", "d", "e", "f");
            //添加集合f
            set.add("set-f", "e", "f", "g", "h");
    
            //求差集(属于d不属于e和f)
            Set<String> difference = set.difference("set-d", Arrays.asList("set-e", "set-f"));
            System.out.println(difference);
    
        }
    
    }