使用开源方案：redisson
github地址：
https://github.com/redisson/redisson/tree/master/redisson-tomcat
redisson.conf 文件配置：
https://github.com/redisson/redisson/wiki/2.-Configuration#26-single-instance-mode
使用方法：
第一步：下载对应的jdk、tomcat版本jar包，一共两个：redisson-all-VERSION.jar、redisson-tomcat-VERSION.jar
第二步：将下载好的jar包上传到tomcat的lib目录下： /usr/local/src/tomcat8/lib
第三步：在/usr/local/src/tomcat8/conf/context.xml 配置redisson.conf 文件目录
<Manager className="org.redisson.tomcat.RedissonSessionManager"
configPath="${catalina.base}/conf/redisson.conf" readMode="REDIS" updateMode="DEFAULT"/>
备注：配置属性里的readMode和updateMode需要注意(选用redis存储session时，需要将readMode改为REDIS)：
readMode - read attributes mode. Two modes are available:
MEMORY- read attributes stored in local Tomcat Session. Default mode.REDIS- read directly from Redis.
updateMode - attributes update mode. Two modes are available:
DEFAULT- session attributes are stored into Redis only through setAttribute method. Default mode.AFTER_REQUEST- all session attributes are stored into Redis after each request.
第四步：配置redisson需要的数据信息 redisson.conf (参考redisson的wiki文档，我使用的单节点模式，找到相应的配置内容)：
{
"singleServerConfig":{
"address": "redis://127.0.0.1:6379",
"password":"****your password***",
"database":0,
"idleConnectionTimeout":10000,
"pingTimeout":1000,
"connectTimeout":10000,
"timeout":3000,
"retryAttempts":3,
"retryInterval":1500,
"subscriptionsPerConnection":5,
"clientName":null,
"subscriptionConnectionMinimumIdleSize":1,
"subscriptionConnectionPoolSize":50,
"connectionMinimumIdleSize":32,
"connectionPoolSize":64,
"dnsMonitoringInterval":5000
},
"threads":0,
"nettyThreads":0,
"codec":{
"class":"org.redisson.codec.JsonJacksonCodec"
},
"transportMode":"NIO"
}
第五步：重启tomcat后就可以看到redis里有redisson为key的session缓存数据了