hyperloglog应用

1.hyperloglog是应用在基数计算上。因为它不去存储数据，而是计算存储key值的数量，在 Redis 里面，每个 HyperLogLog 键只需要花费 12 KB 内存，就可以计算接近 2^64 个不同元素的基数。这和计算基数时，元素越多耗费内存就越多的集合形成鲜明对比。

2.hyperloglog基本redis语句

http://www.runoob.com/redis/redis-hyperloglog.html

3.基于redisTemplate操作

package com.panku.web.redis; 
import java.util.Collection; 
import java.util.Set;import javax.annotation.Resource;import org.junit.Test; 
import org.junit.runner.RunWith; 
import org.Springframework.dao.DataAccessException; 
import org.springframework.data.redis.connection.DataType; 
import org.springframework.data.redis.connection.RedisConnection; 
import org.springframework.data.redis.core.HyperLogLogOperations; 
import org.springframework.data.redis.core.RedisCallback; 
import org.springframework.data.redis.core.RedisTemplate; 
import org.springframework.data.redis.core.ZSetOperations.TypedTuple; 
import org.springframework.test.context.ContextConfiguration; 
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; 
/** 
 * Spring RedisTemplate操作-HyperLogLog操作 
 * @author ccx 
 * 
 */ 
@RunWith(SpringJUnit4ClassRunner.class)   
@ContextConfiguration(locations = "classpath:applicationContext.xml")   
public class RedisTemplateHyperLogLog { 
    @Resource(name="redisTemplate") 
    private RedisTemplate rt; 
     
    public void flushdb(){ 
        rt.execute(new RedisCallback () {
            public String doInRedis(RedisConnection connection) throws DataAccessException {
                connection.flushDb();
                return "ok";
            }
        });
    }
    @Test
    public void set(){
        flushdb();
        HyperLogLogOperations vo = rt.opsForHyperLogLog(); 
        vo.add("book", "a","b","c"); 
        vo.add("bag", "a","e","d"); 
        vo.add("del", "f","g","h"); 
         
         
         
    } 
    @Test 
    public void get(){ 
        HyperLogLogOperations vo = rt.opsForHyperLogLog(); 
        out(vo.size("book")); 
        out(vo.size("bag")); 
        out(vo.size("del")); 
        out(vo.size("book","bag","del")); 
        vo.delete("del"); 
        out(vo.size("book","bag","del")); 
        vo.union("total", "book","bag","del"); 
        out(vo.size("total")); 
    } 
     
    public void out(String str){ 
        System.out.println(str); 
    } 
    public void out(Collection list){ 
        System.out.println(list); 
    } 
    public void out(long num){ 
        System.out.println(num); 
    } 
    public void out(boolean num){ 
        System.out.println(num); 
    } 
    public void out(DataType num){ 
        System.out.println(num); 
    } 
    public void out(Object str){ 
        System.out.println(str); 
    } 
    public void out(Set > set){ 
        for(TypedTuple t : set){ 
            System.out.println(t.getValue()+"---"+t.getScore()); 
        } 
    } 
}

https://www.aliyun.com/jiaocheng/775199.html?spm=5176.100033.2.5.htLH4i

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