+ add putIfAbsent on Hash operations

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/core/BoundHashOperations.java

@@ -36,6 +36,8 @@ public interface BoundHashOperations<H, HK, HV> extends KeyBound<H> {
 
 	void put(HK key, HV value);
 
+	Boolean putIfAbsent(HK key, HV value);
+
 	Collection<HV> multiGet(Collection<HK> keys);
 
 	void putAll(Map<? extends HK, ? extends HV> m);

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/core/DefaultBoundHashOperations.java

@@ -89,6 +89,11 @@ class DefaultBoundHashOperations<H, HK, HV> extends DefaultKeyBound<H> implement
 		ops.put(getKey(), key, value);
 	}
 
+	@Override
+	public Boolean putIfAbsent(HK key, HV value) {
+		return ops.putIfAbsent(getKey(), key, value);
+	}
+
 	@Override
 	public Collection<HV> values() {
 		return ops.values(getKey());

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/core/HashOperations.java

@@ -44,6 +44,8 @@ public interface HashOperations<H, HK, HV> {
 
 	void put(H key, HK hashKey, HV value);
 
+	Boolean putIfAbsent(H key, HK hashKey, HV value);
+
 	Collection<HV> values(H key);
 
 	Map<HK, HV> entries(H key);

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/core/RedisTemplate.java

@@ -1606,6 +1606,21 @@ public class RedisTemplate<K, V> extends RedisAccessor implements RedisOperation
 			}, true);
 		}
 
+		@Override
+		public Boolean putIfAbsent(K key, HK hashKey, HV value) {
+			final byte[] rawKey = rawKey(key);
+			final byte[] rawHashKey = rawHashKey(hashKey);
+			final byte[] rawHashValue = rawHashValue(value);
+
+			return execute(new RedisCallback<Boolean>() {
+				@Override
+				public Boolean doInRedis(RedisConnection connection) {
+					return connection.hSetNX(rawKey, rawHashKey, rawHashValue);
+				}
+			}, true);
+		}
+
+
 		@SuppressWarnings("unchecked")
 		@Override
 		public List<HV> values(K key) {