RedisTemplate访问Redis数据结构（三）——Hash

我就是我 2021-09-15 18:18 570阅读 1赞

[https://blog.csdn.net/weixin\_37490221/article/details/78135036][https_blog.csdn.net_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）][RedisTemplate_Redis]）

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
             */
        }

[https_blog.csdn.net_weixin_37490221_article_details_78135036]: https://blog.csdn.net/weixin_37490221/article/details/78135036
[RedisTemplate_Redis]: http://blog.csdn.net/weixin_37490221/article/details/78134105