redisTemplate不支持zpopmax，解决方案使用reverseRangeWithScore

在redis客户端可以使用zpopmax

redisTemplate不支持zpopmax

解决方案

使用reverseRangeWithScore
接下来我们进行测试

我们要返回最大的value，应该是c

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.ZSetOperations;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.Set;

@SpringBootTest
@RunWith(SpringRunner.class)
public class TEST1 {
    
    

    @Autowired
    private RedisTemplate redisTemplate;

    @Test
    public void Data(){
    
    
//        redisTemplate.opsForZSet().add("goods","a",10);
//        redisTemplate.opsForZSet().add("goods","b",10);
//        redisTemplate.opsForZSet().add("goods","c",11);
        String goods = zPopMaxFromSet("goods");
        System.out.println(goods);

    }


    public String zPopMaxFromSet(String setName) {
    
    
        ZSetOperations<String, String> zSetOperations = redisTemplate.opsForZSet();
        Set<ZSetOperations.TypedTuple<String>> maxElements = zSetOperations.reverseRangeWithScores(setName, 0, 0);

        if (!maxElements.isEmpty()) {
    
    
            ZSetOperations.TypedTuple<String> maxElement = maxElements.iterator().next();
            //获取值
            String element = maxElement.getValue();
            //获取得分
            Double score = maxElement.getScore();
            zSetOperations.remove(setName, element);
            return element;
        }
        return null; // 集合为空
    }
}

有人想问了zSetOperations.reverseRangeWithScores(setName, 0, 0); 0,0代表什么
开始索引位置和结束位置


测试

    @ApiOperation("测试")
    @GetMapping("/test/{start}/{end}")
    public List<String> testRedis(@PathVariable Integer start, @PathVariable Integer end){
    
    
        ZSetOperations<String, String> zSetOperations = redisTemplate.opsForZSet();
        Set<ZSetOperations.TypedTuple<String>> maxElements = zSetOperations.reverseRangeWithScores("goods", start,end );
        Iterator<ZSetOperations.TypedTuple<String>> iterator = maxElements.iterator();
        ArrayList<String> list = new ArrayList<>();
        while(iterator.hasNext()){
    
    
            list.add(iterator.next().getValue());

        }
        return list; // 集合为空
    }

记得序列化

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import java.io.Serializable;



@Configuration
public class RedisConfig {
    
    
    /**
     * @param lettuceConnectionFactory
     * @return
     *
     * redis序列化的工具配置类，下面这个请一定开启配置
     * 127.0.0.1:6379> keys *
     * 1) "ord:102"  序列化过
     * 2) "\xac\xed\x00\x05t\x00\aord:102"   野生，没有序列化过
     */
    @Bean
    public RedisTemplate redisTemplate(LettuceConnectionFactory lettuceConnectionFactory) {
    
    
        RedisTemplate redisTemplate = new RedisTemplate();

        redisTemplate.setConnectionFactory(lettuceConnectionFactory);
        //设置key序列化方式string
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        //设置value的序列化方式json
        redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());

        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());

        redisTemplate.afterPropertiesSet();

        return redisTemplate;
    }
}