spring boot 集成 redis 出现 “Unable to connect to localhost:6379”

当访问到代码

redisTemplate.opsForValue();

时，出现以下错误：

org.springframework.data.redis.RedisConnectionFailureException: Unable to connect to Redis; nested exception is io.lettuce.core.RedisConnectionException: Unable to connect to localhost:6379
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getNativeConnection(LettuceConnectionFactory.java:1092) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getConnection(LettuceConnectionFactory.java:1065) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getSharedConnection(LettuceConnectionFactory.java:865) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getConnection(LettuceConnectionFactory.java:340) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.core.RedisConnectionUtils.doGetConnection(RedisConnectionUtils.java:132) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:95) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:82) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:211) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:184) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:95) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.core.DefaultValueOperations.get(DefaultValueOperations.java:53) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]

【参考】

https://xinghua24.github.io/SpringBoot/Spring-Boot-Spring-Data-Redis/

https://github.com/xinghua24/SpringBootExamples/tree/master/data-redis
Need to add @EnableRedisRepositories annotation and create beans for connection factory and redisTemplate

【解决】