配置缓存时报错: Connection refused: no further information

项目配置缓存时出错, 错误信息如下

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.data.redis.RedisConnectionFailureException: Unable to connect to Redis; nested exception is io.lettuce.core.RedisConnectionException: Unable to connect to localhost:6379] with root cause

java.net.ConnectException: Connection refused: no further information

at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) ~[na:1.8.0_101]
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717) ~[na:1.8.0_101]
at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:330) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final]
at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:334) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:702) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) ~[netty-common-4.1.51.Final.jar:4.1.51.Final]
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.51.Final.jar:4.1.51.Final]
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.51.Final.jar:4.1.51.Final]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_101]

原因

Maven 依赖中使用了两个缓存依赖, 去掉一个即可

<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-cacheartifactId>
dependency>
<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-data-redisartifactId>
dependency>