RedisTemplate操做命令 - Hash

 

Hash操做

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* 看別人的總沒有本身實操來的印象深入

redis的五大數據類型 字符串、列表、集合、有序集合、哈希

redis的哈希類型指的是鍵值自己又是一個鍵值對結構：

如：vaule = {{key1,value1},{key2,value2}...{keyn,valuen}}

相對於java能夠理解爲map：Key=>(Map<HK,HV>)

 

哈希類型的內部編碼有兩種：

ziplist（壓縮列表）：當哈希類型元素個數小於hash-max-ziplist-entries配置（默認512個）、同時全部值都小於hash-max-ziplist-value配置（默認64字節）時，Redis會使用ziplist做爲哈希的內部實現，ziplist使用更加緊湊的結構實現多個元素的連續存儲，因此在節省內存方面比hashtable更加優秀。

hashtable（哈希表）：當哈希類型沒法知足ziplist的條件時，Redis會使用hashtable做爲哈希的內部實現，由於此時ziplist的讀寫效率會降低，而hashtable的讀寫時間複雜度爲O（1）。

 

在redis開發與運維中的圖解：

 

redis對哈希的命令在redisTemplate中都有映射，見下方表：

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redisTemplate

//如下表格使用hash代替redisTemplate.opsForHash() : HashOperations hash = redisTemplate.opsForHash();

命令	操做	返回值
hash.delete(H key, Object... hashKeys)	刪除，能夠傳入多個map的key【hdel】	Long
hash.hasKey(key, hashKey)	查看hash中的某個hashKey是否存在【hexists】	Boolean
hash.get(key, hashKey)	獲取值【hget】	Object（HV 泛型約束對象）
hash.multiGet(H key, Collection<HK> hashKeys)	批量獲取集合中的key對應的值【hmget】	List<HV>
hash.increment(H key, HK hashKey, long delta)	對值進行+(delta值)操做【】	Long
hash.increment(H key, HK hashKey, double delta)	~	double
hash.keys(key)	返回map內hashKey的集合【hkeys】	Set<HK>
hash.lengthOfValue(H key, HK hashKey)	返回查詢鍵關聯的值的長度，爲null則返回0【hstrlen】	Long
hash.size(H key)	獲取hashKey的個數【hlen】	Long
hash.putAll(H key, Map<? extends HK, ? extends HV> m)	至關於map的putAll【hmset】	void
hash.put(H key, HK hashKey, HV value)	設置值，添加hashKey-value，hashKay至關於map的key 【hset】	void
hash.putIfAbsent(H key, HK hashKey, HV value)	僅當hashKey不存在時設置值	Boolean
hash.values(key)	返回value的集合【hvals】	List<HV>
hase.entries(H key)	獲取map【hgetall】	Map<HK, HV>
hash.scan(H key, ScanOptions options)	基於遊標的迭代查詢【hscan】	Cursor<Map.Entry<HK, HV>>（返回的Cursor要手動關閉，見下面示例2）
hash.getOperations()	返回RedisOperation，它就是redis操做的接口	RedisOperations<H, ?>

 

 對於命令的時間複雜度見下表：

示例測試操做1：

 　　　　//key
        String k = "phoneMap";
        //map的key
        String hashKey = "13838383838";

        Map<String, String> phoneMap = new HashMap<>();
        phoneMap.put("13838383839","1");
        phoneMap.put(hashKey,"2");

        //添加map
        //redisTemplate.opsForHash().putAll(k, phoneMap);

        //在key的value中添加單個hash值
        redisTemplate.opsForHash().put(k, "19199999999","2");

        //獲取map
        Map m1 = redisTemplate.opsForHash().entries(k);
        Object o = redisTemplate.opsForHash().get(k, hashKey);
        log.info("get key:{}", o);
        log.info("map:{}", m1);

 

log打印的結果：

2019-12-13 15:45:36.836 INFO 4156 --- [ main] : get key:null
2019-12-13 15:45:36.836 INFO 4156 --- [ main] : map:{13838121333=1, 13838121556=2, 19199999999=2}

若是這裏使用了redisTemplate.opsForHash().putAll(k, phoneMap); ，則get key打印的結果就是2。這裏打印的map是包含以前測試的值。

 

示例測試操做2：

    @Test
    public void hashTest(){
        String k = "phoneMap";
        String hashKey = "19199999999";
        HashOperations<String, String, String> hash = redisTemplate.opsForHash();
        hash.increment(k,hashKey,1);
        log.info("19199999999:{}", hash.get(k,hashKey));

        Set set = hash.keys(k);
        log.info("phoneMap:{}", set);

        Long sizeLong = hash.size(k);
        log.info("sizeLong:{}",sizeLong);


        Cursor<Map.Entry<String, String>> cursor = hash.scan(k,ScanOptions.scanOptions().count(1000).build());
        while (cursor.hasNext()){
            Map.Entry<String, String> entry = cursor.next();
            log.info("entry:{}:{}", entry.getKey(), entry.getValue());
        }
        try {
            if (!cursor.isClosed()){
                cursor.close();
            }
        } catch (IOException e) {
            log.error("關閉cursor異常");
            e.printStackTrace();
        }
    }

打印結果：

2019-12-13 16:59:35.573  INFO 1540 --- [           main] : 19199999999:6
2019-12-13 16:59:35.577  INFO 1540 --- [           main] : phoneMap:[13838121333, 13838121556, 19199999999, 13838383839, 13838383838]
2019-12-13 16:59:35.578  INFO 1540 --- [           main] : sizeLong:5
2019-12-13 16:59:35.587  INFO 1540 --- [           main] : entry:13838121373:1
2019-12-13 16:59:35.587  INFO 1540 --- [           main] : entry:13838121556:2
2019-12-13 16:59:35.587  INFO 1540 --- [           main] : entry:19199999999:6
2019-12-13 16:59:35.587  INFO 1540 --- [           main] : entry:13838383839:1
2019-12-13 16:59:35.587  INFO 1540 --- [           main] : entry:13838383838:2

 

# 使用文件形式展現：

 

 

 

private final String REDIS_PHONE_CONUM_PREFIX_KEY = "phoneSms:Check";


/**
     * 添加手機號發送次數
     * @param phone
     * @return
     */
    public void setPhoneSmsCountInc(String phone){
        HashOperations hash = redisTemplate.opsForHash();
        if (!redisTemplate.hasKey(REDIS_PHONE_CONUM_PREFIX_KEY)){
            //設置過時key時間
            redisTemplate.expire(REDIS_PHONE_CONUM_PREFIX_KEY, 24 * 60 * 60, TimeUnit.SECONDS);
        }
        hash.increment(REDIS_PHONE_CONUM_PREFIX_KEY, phone,1);
    }

　　

 

 

這是HashOperations的源碼：

/*
 * Copyright 2011-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.data.redis.core;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.lang.Nullable;

/**
 * Redis map specific operations working on a hash.
 *
 * @author Costin Leau
 * @author Christoph Strobl
 * @author Ninad Divadkar
 */
public interface HashOperations<H, HK, HV> {

    /**
     * Delete given hash {@code hashKeys}.
     *
     * @param key must not be {@literal null}.
     * @param hashKeys must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     */
    Long delete(H key, Object... hashKeys);

    /**
     * Determine if given hash {@code hashKey} exists.
     *
     * @param key must not be {@literal null}.
     * @param hashKey must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     */
    Boolean hasKey(H key, Object hashKey);

    /**
     * Get value for given {@code hashKey} from hash at {@code key}.
     *
     * @param key must not be {@literal null}.
     * @param hashKey must not be {@literal null}.
     * @return {@literal null} when key or hashKey does not exist or used in pipeline / transaction.
     */
    @Nullable
    HV get(H key, Object hashKey);

    /**
     * Get values for given {@code hashKeys} from hash at {@code key}.
     *
     * @param key must not be {@literal null}.
     * @param hashKeys must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     */
    List<HV> multiGet(H key, Collection<HK> hashKeys);

    /**
     * Increment {@code value} of a hash {@code hashKey} by the given {@code delta}.
     *
     * @param key must not be {@literal null}.
     * @param hashKey must not be {@literal null}.
     * @param delta
     * @return {@literal null} when used in pipeline / transaction.
     */
    Long increment(H key, HK hashKey, long delta);

    /**
     * Increment {@code value} of a hash {@code hashKey} by the given {@code delta}.
     *
     * @param key must not be {@literal null}.
     * @param hashKey must not be {@literal null}.
     * @param delta
     * @return {@literal null} when used in pipeline / transaction.
     */
    Double increment(H key, HK hashKey, double delta);

    /**
     * Get key set (fields) of hash at {@code key}.
     *
     * @param key must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     */
    Set<HK> keys(H key);

    /**
     * Returns the length of the value associated with {@code hashKey}. If either the {@code key} or the {@code hashKey}
     * do not exist, {@code 0} is returned.
     *
     * @param key must not be {@literal null}.
     * @param hashKey must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     * @since 2.1
     */
    @Nullable
    Long lengthOfValue(H key, HK hashKey);

    /**
     * Get size of hash at {@code key}.
     *
     * @param key must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     */
    Long size(H key);

    /**
     * Set multiple hash fields to multiple values using data provided in {@code m}.
     *
     * @param key must not be {@literal null}.
     * @param m must not be {@literal null}.
     */
    void putAll(H key, Map<? extends HK, ? extends HV> m);

    /**
     * Set the {@code value} of a hash {@code hashKey}.
     *
     * @param key must not be {@literal null}.
     * @param hashKey must not be {@literal null}.
     * @param value
     */
    void put(H key, HK hashKey, HV value);

    /**
     * Set the {@code value} of a hash {@code hashKey} only if {@code hashKey} does not exist.
     *
     * @param key must not be {@literal null}.
     * @param hashKey must not be {@literal null}.
     * @param value
     * @return {@literal null} when used in pipeline / transaction.
     */
    Boolean putIfAbsent(H key, HK hashKey, HV value);

    /**
     * Get entry set (values) of hash at {@code key}.
     *
     * @param key must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     */
    List<HV> values(H key);

    /**
     * Get entire hash stored at {@code key}.
     *
     * @param key must not be {@literal null}.
     * @return {@literal null} when used in pipeline / transaction.
     */
    Map<HK, HV> entries(H key);

    /**
     * Use a {@link Cursor} to iterate over entries in hash at {@code key}. <br />
     * <strong>Important:</strong> Call {@link Cursor#close()} when done to avoid resource leak.
     *
     * @param key must not be {@literal null}.
     * @param options
     * @return {@literal null} when used in pipeline / transaction.
     * @since 1.4
     */
    Cursor<Map.Entry<HK, HV>> scan(H key, ScanOptions options);

    /**
     * @return never {@literal null}.
     */
    RedisOperations<H, ?> getOperations();
}

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