Tomcat可以实现Session共享方案

说明：原来Tomcat也是可以实现Session共享的，这样大大减少的硬编码的实现，并且前面用Nginx分流时不用考虑Session的问题，因为是Web容器提供了Session共享的支持。

1、在每个Tomcat的conf目录下，找到server.xml文件，增加如下内容：

        <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"
                 channelSendOptions="8">

          <Manager className="org.apache.catalina.ha.session.DeltaManager"
                   expireSessionsOnShutdown="false"
                   notifyListenersOnReplication="true"/>

          <Channel className="org.apache.catalina.tribes.group.GroupChannel">
            <Membership className="org.apache.catalina.tribes.membership.McastService"
                        address="228.0.0.4"
                        port="45564"
                        frequency="500"
                        dropTime="3000"/>
            <Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"
                      address="auto"
                      port="4000"
                      autoBind="100"
                      selectorTimeout="5000"
                      maxThreads="6"/>

            <Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">
              <Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/>
            </Sender>
            <Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/>
            <Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor"/>
          </Channel>

          <Valve className="org.apache.catalina.ha.tcp.ReplicationValve"
                 filter=""/>
          <Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve"/>

          <Deployer className="org.apache.catalina.ha.deploy.FarmWarDeployer"
                    tempDir="/tmp/war-temp/"
                    deployDir="/tmp/war-deploy/"
                    watchDir="/tmp/war-listen/"
                    watchEnabled="false"/>

          <ClusterListener className="org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener">
          <ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener">
        </Cluster>

在这个下面增加<Engine name="Catalina" defaultHost="localhost">即可。

2、在项目的web.xml中增加<distributable>

参考：

http://tomcat.apache.org/tomcat-7.0-doc/cluster-howto.html（官方文档）

http://blog.csdn.net/qh_java/article/details/45955923

http://blog.csdn.net/wlwlwlwl015/article/details/48160433