方式一

• 在context.xml配置resource

<Resource 
   name="jdbc/tbplus" 
   auth="Container" 
   type="javax.sql.DataSource"
   maxActive="100" 
   maxIdle="30" 
   maxWait="10000"
   username="root" 
   password="a123456"
   driverClassName="com.mysql.jdbc.Driver"
   url="jdbc:mysql://127.0.0.1:3306/bearoff"
/>

• 完整的context.xml

  <?xml version="1.0" encoding="utf-8"?>
  
  <!--
    Licensed to the Apache Software Foundation (ASF) under one or more
    contributor license agreements.  See the NOTICE file distributed with
    this work for additional information regarding copyright ownership.
    The ASF licenses this file to You under the Apache License, Version 2.0
    (the "License"); you may not use this file except in compliance with
    the License.  You may obtain a copy of the License at
  
        http://www.apache.org/licenses/LICENSE-2.0
  
    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
  -->
  <!-- The contents of this file will be loaded for each web application -->
  <Context> 
    <!-- Default set of monitored resources -->  
    <WatchedResource>WEB-INF/web.xml</WatchedResource>  
    <!-- Uncomment this to disable session persistence across Tomcat restarts -->  
    <!--
      <Manager pathname="" />
      -->  
    <!-- Uncomment this to enable Comet connection tacking (provides events
           on session expiration as well as webapp lifecycle) -->  
    <!--
      <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
      -->  
    <Resource 
  	name="jdbc/bearoff-rm" 
  	auth="Container" 
  	type="javax.sql.DataSource" 
  	username="root" 
  	password="a123456" 
  	driverClassName="com.mysql.jdbc.Driver" 
  	url="jdbc:mysql://127.0.0.1:3306/bearoff" 
  	maxActive="30" 
  	maxIdle="10" 
  	maxWait="10000"/>  
    <Resource 
  	name="jdbc/bearoff-rr" 
  	auth="Container" 
  	type="javax.sql.DataSource" 
  	username="root" 
  	password="a123456" 
  	driverClassName="com.mysql.jdbc.Driver" 
  	url="jdbc:mysql://127.0.0.1:3306/bearoff_slave" 
  	maxActive="30" 
  	maxIdle="10" 
  	maxWait="10000"/> 
  </Context>

上面完成的context.xml是配置的双数据源，是读写分离的配置，一个主数据库一个从数据库

方式二

配置context.xml和server.xml

• server.xml

• 在Resource name=”UserDatabase”下面新增如下内容：

  <Resource 
     name="jdbc/tbplus" 
     auth="Container" 
     type="javax.sql.DataSource"
     maxActive="100" 
     maxIdle="30" 
     maxWait="10000"
     username="sa" 
     password="a123456" 
     factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"
     driverClassName="com.microsoft.sqlserver.jdbc.SQLServerDriver"
     url="jdbc:sqlserver://127.0.0.1:1433;DatabaseName=tbplus"
  />

• context.xml

  配置ResourceLink

  <ResourceLink 
  	global="jdbc/tbplus" 
  	name="jdbc/tbplus" 
  	type="javax.sql.DataSource" 
  />  

• 完整的server.xml

  <?xml version="1.0" encoding="utf-8"?>
  
  <!--
    Licensed to the Apache Software Foundation (ASF) under one or more
    contributor license agreements.  See the NOTICE file distributed with
    this work for additional information regarding copyright ownership.
    The ASF licenses this file to You under the Apache License, Version 2.0
    (the "License"); you may not use this file except in compliance with
    the License.  You may obtain a copy of the License at
  
        http://www.apache.org/licenses/LICENSE-2.0
  
    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
  -->
  <!-- Note:  A "Server" is not itself a "Container", so you may not
       define subcomponents such as "Valves" at this level.
       Documentation at /docs/config/server.html
   -->
  <Server port="8005" shutdown="SHUTDOWN"> 
    <Listener className="org.apache.catalina.startup.VersionLoggerListener"/>  
    <!-- Security listener. Documentation at /docs/config/listeners.html
    <Listener className="org.apache.catalina.security.SecurityListener" />
    -->  
    <!--APR library loader. Documentation at /docs/apr.html -->  
    <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on"/>  
    <!--Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html -->  
    <Listener className="org.apache.catalina.core.JasperListener"/>  
    <!-- Prevent memory leaks due to use of particular java/javax APIs-->  
    <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener"/>  
    <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"/>  
    <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener"/>  
    <!-- Global JNDI resources
         Documentation at /docs/jndi-resources-howto.html
    -->  
    <GlobalNamingResources> 
      <!-- Editable user database that can also be used by
           UserDatabaseRealm to authenticate users
      -->  
      <Resource name="UserDatabase" auth="Container" type="org.apache.catalina.UserDatabase" description="User database that can be updated and saved" factory="org.apache.catalina.users.MemoryUserDatabaseFactory" pathname="conf/tomcat-users.xml"/>  
      <Resource name="jdbc/tbplus" auth="Container" type="javax.sql.DataSource" maxActive="100" maxIdle="30" maxWait="10000" username="sa" password="a123456" factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory" driverClassName="com.microsoft.sqlserver.jdbc.SQLServerDriver" url="jdbc:sqlserver://127.0.0.1:1433;DatabaseName=tbplus"/> 
    </GlobalNamingResources>  
    <!-- A "Service" is a collection of one or more "Connectors" that share
         a single "Container" Note:  A "Service" is not itself a "Container",
         so you may not define subcomponents such as "Valves" at this level.
         Documentation at /docs/config/service.html
     -->  
    <Service name="Catalina"> 
      <!--The connectors can use a shared executor, you can define one or more named thread pools-->  
      <!--
      <Executor name="tomcatThreadPool" namePrefix="catalina-exec-"
          maxThreads="150" minSpareThreads="4"/>
      -->  
      <!-- A "Connector" represents an endpoint by which requests are received
           and responses are returned. Documentation at :
           Java HTTP Connector: /docs/config/http.html (blocking & non-blocking)
           Java AJP  Connector: /docs/config/ajp.html
           APR (HTTP/AJP) Connector: /docs/apr.html
           Define a non-SSL HTTP/1.1 Connector on port 8080
      -->  
      <Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" URIEncoding="UTF-8" maxThreads="250" maxHttpHeaderSize="8192" disableUploadTimeout="true" acceptCount="80" emptySessionPath="true" enableLookups="false" compression="500" compressableMimeType="text/html,text/xml,text/plain,application/octet-stream"/>  
      <!-- A "Connector" using the shared thread pool-->  
      <!--
      <Connector executor="tomcatThreadPool"
                 port="8080" protocol="HTTP/1.1"
                 connectionTimeout="20000"
                 redirectPort="8443" />
      -->  
      <!-- Define a SSL HTTP/1.1 Connector on port 8443
           This connector uses the BIO implementation that requires the JSSE
           style configuration. When using the APR/native implementation, the
           OpenSSL style configuration is required as described in the APR/native
           documentation -->  
      <!--
      <Connector port="8443" protocol="org.apache.coyote.http11.Http11Protocol"
                 maxThreads="150" SSLEnabled="true" scheme="https" secure="true"
                 clientAuth="false" sslProtocol="TLS" />
      -->  
      <!-- Define an AJP 1.3 Connector on port 8009 -->  
      <Connector port="8009" protocol="AJP/1.3" redirectPort="8443"/>  
      <!-- An Engine represents the entry point (within Catalina) that processes
           every request.  The Engine implementation for Tomcat stand alone
           analyzes the HTTP headers included with the request, and passes them
           on to the appropriate Host (virtual host).
           Documentation at /docs/config/engine.html -->  
      <!-- You should set jvmRoute to support load-balancing via AJP ie :
      <Engine name="Catalina" defaultHost="localhost" jvmRoute="jvm1">
      -->  
      <Engine name="Catalina" defaultHost="localhost"> 
        <!--For clustering, please take a look at documentation at:
            /docs/cluster-howto.html  (simple how to)
            /docs/config/cluster.html (reference documentation) -->  
        <!--
        <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
        -->  
        <!-- Use the LockOutRealm to prevent attempts to guess user passwords
             via a brute-force attack -->  
        <Realm className="org.apache.catalina.realm.LockOutRealm"> 
          <!-- This Realm uses the UserDatabase configured in the global JNDI
               resources under the key "UserDatabase".  Any edits
               that are performed against this UserDatabase are immediately
               available for use by the Realm.  -->  
          <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/> 
        </Realm>  
        <Host name="localhost" appBase="webapps" unpackWARs="true" autoDeploy="true"> 
          <!-- SingleSignOn valve, share authentication between web applications
               Documentation at: /docs/config/valve.html -->  
          <!--
          <Valve className="org.apache.catalina.authenticator.SingleSignOn" />
          -->  
          <!-- Access log processes all example.
               Documentation at: /docs/config/valve.html
               Note: The pattern used is equivalent to using pattern="common" -->  
          <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs" prefix="localhost_access_log." suffix=".txt" pattern="%h %l %u %t &quot;%r&quot; %s %b"/> 
        </Host> 
      </Engine> 
    </Service> 
  </Server>

• 完整的context.xml

  <?xml version="1.0" encoding="utf-8"?>
  
  <!--
    Licensed to the Apache Software Foundation (ASF) under one or more
    contributor license agreements.  See the NOTICE file distributed with
    this work for additional information regarding copyright ownership.
    The ASF licenses this file to You under the Apache License, Version 2.0
    (the "License"); you may not use this file except in compliance with
    the License.  You may obtain a copy of the License at
  
        http://www.apache.org/licenses/LICENSE-2.0
  
    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
  -->
  <!-- The contents of this file will be loaded for each web application -->
  <Context> 
    <!-- Default set of monitored resources -->  
    <WatchedResource>WEB-INF/web.xml</WatchedResource>  
    <!-- Uncomment this to disable session persistence across Tomcat restarts -->  
    <!--
      <Manager pathname="" />
      -->  
    <!-- Uncomment this to enable Comet connection tacking (provides events
           on session expiration as well as webapp lifecycle) -->  
    <!--
      <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
      -->  
    <ResourceLink global="jdbc/tbplus" name="jdbc/tbplus" type="javax.sql.DataSource"/> 
  </Context>

备注

• mysql driverName

  com.mysql.jdbc.Driver

• sqlserver driverName

  com.microsoft.sqlserver.jdbc.SQLServerDriver