RedisTemplate使用最详解（三）--- opsForHash()

1、put(H var1, HK var2, HV var3)

新增hashMap值

• var1 为Redis的key
• var2 为key对应的map值的key
• var3 为key对应的map值的值
• var2相同替换var3

redisTemplate.opsForHash().put("hashValue","map1","value1");
redisTemplate.opsForHash().put("hashValue","map2","value2");

2、get(H var1, Object var2)

获取key对应的map中，key为var2的map的对应的值

Object o = redisTemplate.opsForHash().get("hashValue", "map1");
System.out.println("o = " + o);

3、entries(H key)

获取key对应的所有map键值对

Map hashValue = redisTemplate.opsForHash().entries("hashValue");
System.out.println("hashValue = " + hashValue);

4、keys(H key)

获取key对应的map中所有的键

Set hashValue = redisTemplate.opsForHash().keys("hashValue");
System.out.println("hashValue = " + hashValue);

5、values(H key)

获取key对应的map中所有的值

List hashValue = redisTemplate.opsForHash().values("hashValue");
System.out.println("hashValue = " + hashValue);

6、hasKey(H key, Object var2)

判断key对应的map中是否有指定的键

Boolean aBoolean = redisTemplate.opsForHash().hasKey("hashValue", "map1");
System.out.println("aBoolean = " + aBoolean);

7、size(H key)

获取key对应的map的长度

Long hashValue = redisTemplate.opsForHash().size("hashValue");
System.out.println("hashValue = " + hashValue);

8、putIfAbsent(H key, HK var2, HV var3)

如何key对应的map不存在，则新增到map中，存在则不新增也不覆盖

redisTemplate.opsForHash().putIfAbsent("hashValue", "map3", "value3");

9、putAll(H key, Map<? extends HK, ? extends HV> map)

直接以map集合的方式添加key对应的值

• map中key已经存在，覆盖替换
• map中key不存在，新增

Map newMap = new HashMap();
newMap.put("map4","map4");
newMap.put("map5","map5");
redisTemplate.opsForHash().putAll("hashValue",newMap);

10、multiGet(H key, Collection var2)

以集合的方式获取这些键对应的map

List list = new ArrayList<>();
list.add("map1");
list.add("map2");
List hashValue = redisTemplate.opsForHash().multiGet("hashValue", list);
System.out.println("hashValue = " + hashValue);

11、lengthOfValue(H key, HK var2)

获取指定key对应的map集合中，指定键对应的值的长度

Long aLong = redisTemplate.opsForHash().lengthOfValue("hashValue", "map1");
System.out.println("aLong = " + aLong);

12、increment(H key, HK var2, long long1)

使key对应的map中，键var2对应的值以long1自增

Long increment = redisTemplate.opsForHash().increment("hashValue", "map7", 1);
System.out.println("increment = " + increment);

13、increment(H key, HK var2, double d1)

使key对应的map中，键var2对应的值以double类型d1自增

Double increment = redisTemplate.opsForHash().increment("hashValue", "map8", 1.2);
System.out.println("increment = " + increment);

14、scan(H var1, ScanOptions var2)

匹配获取键值对

• ScanOptions.NONE为获取全部键对
• ScanOptions.scanOptions().match(“map1”).build()，匹配获取键位map1的键值对,不能模糊匹配

Cursor<Map.Entry<Object,Object>> cursor = redisTemplate.opsForHash().scan("hashValue",ScanOptions.scanOptions().match("map1").build());
//Cursor<Map.Entry<Object,Object>> cursor = redisTemplate.opsForHash().scan("hashValue",ScanOptions.NONE);
    while (cursor.hasNext()) {
        Map.Entry<Object, Object> entry = cursor.next();
        System.out.println("entry.getKey() = " + entry.getKey());
        System.out.println("entry.getValue() = " + entry.getValue());
    }

15、delete(H key, Object… var2)

删除key对应的map中的键值对

Long delete = redisTemplate.opsForHash().delete("hashValue", "map1", "map2");
System.out.println("delete = " + delete);

16、拓展

map中存储对象、对象集合时最好转为JSON字符串，容易解析

map中键值对都可以存为对象、对象集合JSON字符串，具体看实际应用存储

List<MPEntity> list = mpService.list();
redisTemplate.opsForHash().put("hashValue",JSON.toJSONString(list),JSON.toJSONString(list));