Return cached HashOperations instance from opsForHash.

Closes spring-projects#2970

Author: mp911de

src/main/java/org/springframework/data/redis/core/RedisTemplate.java

@@ -116,6 +116,7 @@ public class RedisTemplate<K, V> extends RedisAccessor implements RedisOperation
 ObjectHashMapper.getSharedInstance());
 private final ZSetOperations<K, V> zSetOps = new DefaultZSetOperations<>(this);
 private final GeoOperations<K, V> geoOps = new DefaultGeoOperations<>(this);
+private final HashOperations<K, ?, ?> hashOps = new DefaultHashOperations<>(this);
 private final HyperLogLogOperations<K, V> hllOps = new DefaultHyperLogLogOperations<>(this);
 private final ClusterOperations<K, V> clusterOps = new DefaultClusterOperations<>(this);
 
@@ -977,7 +978,7 @@ public <HK, HV> BoundHashOperations<K, HK, HV> boundHashOps(K key) {
 
 @Override
 public <HK, HV> HashOperations<K, HK, HV> opsForHash() {
-return new DefaultHashOperations<>(this);
+return (HashOperations) hashOps;
 }
 
 @Override