es版本導致項目啓動報錯

異常日誌：

查看es log：

[2019-04-01T09:34:35,943][WARN ][o.e.t.TcpTransport       ] [-EMJjGk] exception caught on transport layer [Netty4TcpChannel{localAddress=/127.0.0.1:9300, remoteAddress=/127.0.0.1:51014}], closing connection
java.lang.IllegalStateException: Received message from unsupported version: [5.5.0] minimal compatible version is: [5.6.0]
        at org.elasticsearch.transport.InboundMessage.ensureVersionCompatibility(InboundMessage.java:137) ~[elasticsearch-6.7.0.jar:6.7.0]
        at org.elasticsearch.transport.InboundMessage.access$000(InboundMessage.java:39) ~[elasticsearch-6.7.0.jar:6.7.0]
        at org.elasticsearch.transport.InboundMessage$Reader.deserialize(InboundMessage.java:76) ~[elasticsearch-6.7.0.jar:6.7.0]
        at org.elasticsearch.transport.TcpTransport.messageReceived(TcpTransport.java:927) ~[elasticsearch-6.7.0.jar:6.7.0]
        at org.elasticsearch.transport.TcpTransport.inboundMessage(TcpTransport.java:763) [elasticsearch-6.7.0.jar:6.7.0]
        at org.elasticsearch.transport.netty4.Netty4MessageChannelHandler.channelRead(Netty4MessageChannelHandler.java:53) [transport-netty4-client-6.7.0.jar:6.7.0]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:323) [netty-codec-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:297) [netty-codec-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.handler.logging.LoggingHandler.channelRead(LoggingHandler.java:241) [netty-handler-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:656) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysPlain(NioEventLoop.java:556) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:510) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:470) [netty-transport-4.1.32.Final.jar:4.1.32.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:909) [netty-common-4.1.32.Final.jar:4.1.32.Final]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_162]

分析：根據日誌很明顯，本地安裝的版本爲6.7.0，而項目中pom.xml引入的是5.5.0，根據日誌信息，下載es版本5.6.16，再次啓動項目，正常。

項目pom.xml中引入的elasticsearch依賴：

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>transport</artifactId>
    <version>5.5.0</version>
    <exclusions>
        <exclusion>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>5.5.0</version>
</dependency>