RedisTemplate访问Redis数据结构（三）——Hash

https://blog.youkuaiyun.com/weixin_37490221/article/details/78135036

Redis的散列可以让用户将多个键值对存储到一个Redis键里面。此处我们使用redisTemplate，配置如下（详情请见链接：RedisTemplate访问Redis数据结构（前言））

<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">  
    <property name="connectionFactory" ref="jedisConnFactory"/>  
    <property name="keySerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
    </property>
    <property name="hashKeySerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
    </property>
    <property name="valueSerializer">
        <bean class="org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer"/>
    </property>
    <property name="hashValueSerializer">
        <bean class="org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer"/>
    </property>
</bean> 

HashOperations提供一系列方法操作hash。首先初始化spring工厂获得redisTemplate和opsForHash

    private RedisTemplate<String,Object> redisTemplate;
    private HashOperations<String,String,Object> opsForHash;

    @SuppressWarnings("unchecked")
    @Before
    public void before(){
        @SuppressWarnings("resource")
        ApplicationContext context = new ClassPathXmlApplicationContext("/applicationContext.xml");
        redisTemplate = (RedisTemplate<String,Object>)context.getBean("redisTemplate");
        opsForHash = redisTemplate.opsForHash();
    }

void put(H key, HK hashKey, HV value);

Map< HK, HV > entries(H key);

    @Test
    public void testPut(){
        opsForHash.put("he1", "key1", "a");
        opsForHash.put("he1", "key2", "b");
        opsForHash.put("he1", "key3", "c");
        Map<String, Object> entries = opsForHash.entries("he1");
        System.out.println(entries);//{key3=c, key1=a, key2=b}(无序)
    }

void putAll(H key, Map< ? extends HK, ? extends HV > m);

    @Test
    public void testPutAll(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key1", "a");
        param.put("key2", "b");
        param.put("key3", "c");
        opsForHash.putAll("he2", param);
        System.out.println(opsForHash.entries("he2"));//{key2=b, key1=a, key3=c}
    }

Long delete(H key, Object… hashKeys);

    @Test
    public void testDelete(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key1", "a");
        param.put("key2", "b");
        param.put("key3", "c");
        opsForHash.putAll("he3", param);
        System.out.println(opsForHash.entries("he3"));//{key3=c, key2=b, key1=a}
        opsForHash.delete("he3", "key1");
        System.out.println(opsForHash.entries("he3"));//{key2=b, key3=c}
    }

Boolean hasKey(H key, Object hashKey);

    @Test
    public void testHashKey(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key1", "a");
        param.put("key2", "b");
        param.put("key3", "c");
        opsForHash.putAll("he4", param);
        System.out.println(opsForHash.hasKey("he", "key2"));//false
        System.out.println(opsForHash.hasKey("he4", "key4"));//false
        System.out.println(opsForHash.hasKey("he4", "key2"));//true
    }

HV get(H key, Object hashKey);

    @Test
    public void testGet(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key1", "a");
        param.put("key2", "b");
        param.put("key3", "c");
        opsForHash.putAll("he5", param);
        System.out.println(opsForHash.get("he5", "key1"));//a
        System.out.println(opsForHash.get("he5", "key"));//null
    }

List< HV > multiGet(H key, Collection< HK > hashKeys);

    @Test
    public void testMultiGet(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key1", "a");
        param.put("key2", "b");
        param.put("key3", "c");
        opsForHash.putAll("he6", param);
        List<String> keys = new ArrayList<String>();
        keys.add("key1");
        keys.add("key");
        keys.add("key2");
        System.out.println(opsForHash.multiGet("he6", keys));//[a, null, b]
    }

Long increment(H key, HK hashKey, long delta);

Double increment(H key, HK hashKey, double delta);

    @Test
    public void testIncrement(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key1", "a");
        param.put("key2", "b");
        param.put("key3", "c");
        param.put("key4", 4);
        opsForHash.putAll("he7", param);
        System.out.println(opsForHash.increment("he7", "key4", 1));//5
        System.out.println(opsForHash.increment("he7", "key4", 1.1));//6.1
        try {
            opsForHash.increment("he7", "key1", 1);//ERR hash value is not an integer
        } catch (Exception e) {
            e.printStackTrace();
        }
        try {
            opsForHash.increment("he7", "key1", 1.1);//ERR hash value is not a float
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

Set< HK > keys(H key);

    @Test
    public void testKeys(){
        redisTemplate.delete("he8");
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key4", "d");
        param.put("key1", "a");
        param.put("key3", "c");
        param.put("key5", "e");
        param.put("key2", "b");
        opsForHash.putAll("he8", param);
        Set<String> keys = opsForHash.keys("he8");
        System.out.println(keys);//[key4, key3, key5, key2, key1]
    }

Long size(H key);

    @Test
    public void testSize(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key4", "d");
        param.put("key1", "a");
        param.put("key3", "c");
        param.put("key5", "e");
        param.put("key2", "b");
        opsForHash.putAll("he9", param);
        System.out.println(opsForHash.size("he9"));//5
    }

Boolean putIfAbsent(H key, HK hashKey, HV value);

    @Test
    public void testPutIfAbsent(){
        //仅当hashKey不存在时才设置散列hashKey的值。
        System.out.println(opsForHash.putIfAbsent("he10", "key1", "a"));//true
        System.out.println(opsForHash.putIfAbsent("he10", "key1", "a"));//false
    }

List< HV > values(H key);

    @Test
    public void testValues(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key4", "d");
        param.put("key1", "a");
        param.put("key3", "c");
        param.put("key5", "e");
        param.put("key2", "b");
        opsForHash.putAll("he11", param);
        List<Object> values = opsForHash.values("he11");
        System.out.println(values);//[d, c, e, b, a]
    }

Cursor< Map.Entry< HK, HV >> scan(H key, ScanOptions options);

    @Test
    public void testScan(){
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("key4", "d");
        param.put("key1", "a");
        param.put("key3", "c");
        param.put("key5", "e");
        param.put("key2", "b");
        opsForHash.putAll("he13", param);
        Cursor<Map.Entry<String, Object>> curosr = opsForHash.scan("he13", ScanOptions.NONE);
        while(curosr.hasNext()){
            Map.Entry<String, Object> entry = curosr.next();
            System.out.println(entry.getKey()+":"+entry.getValue());
        }
        /**
            key4:d
            key3:c
            key5:e
            key2:b
            key1:a
         */
    }