Xay dung he thong tomcat clustering

1. Installation of JDK
2. Installation Apache web server
3. Installation Tomcat
4. Edit Tomcat server.xml
5. Tomcat web.xml add <distributed /> in WEB-INF
6. Install mod_jk Connector in module
7. Edit in httpd.conf
8. worker.properties file in conf
9. mod_jk.log file in log
10. Restart of Apache and Tomcat
11. Test run Jsp & load balancing

Installation of Jdk

Java can be downloaded from sun and installed.
Sun provides different executable file for Windows and Linux operating system version. Sun provide JDK for Linux in .bin or tar.gz format, and for Windows .exe format.
After downloading file from sun, install JDK simple double click or through command prompt

see more installation of JDK

Installation of apache web server for load balancing and load sharing

Download apache and install on same system for vertical tomcat clustering.
Installation of apache more
After installation of apache, we need to do some configuration
Installation of tomcat

Download tomcat 6 Make three copy of tomcat If want to make three tomcat clustering system then need three copies of tomcat

Cluster 1 tomcatA
Cluster 2 tomcatB
Cluster 3 tomcatC

Horizontal Clustering

Vertical Clustering


If need three cluster then need to make three instance of tomcat
tomcat installation steps


Installation is simple as we install tomcat normally. In this tomcat clustering we are going for vertical tomcat clustering. So all tomcat instance is in single server. If you want (real world clustering) that is also much simpler. Then work with ip instead of localhost, I am also including examples for download
Tomcat server.xml configuration

1. Vertical tomcat clustering( on single machine)
2. Horizontal tomcat clustering( on multiple machine)

Vertical tomcat clustering example

open Tomcat -> Conf -> server.xml
Edit highlighted and can give port which we can required

1 First tomcatA

         <!-- 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="8105" shutdown="SHUTDOWN">           
  <!--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"  />
    <!-- JMX Support  for the Tomcat server. Documentation at  /docs/non-existent.html -->
    <Listener   className="org.apache.catalina.mbeans.ServerLifecycleListener" />
    <Listener   className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"   />
             <!-- 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" />
    </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="8081"   protocol="HTTP/1.1" 
                  connectionTimeout="20000" 
                  redirectPort="8443" />
      <!-- 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 JSSE configuration, when using APR,  the 
           connector  should be using the OpenSSL style configuration
           described in  the APR documentation -->
      <!--
      <Connector  port="8443" protocol="HTTP/1.1" SSLEnabled="true"
                  maxThreads="150" scheme="https"  secure="true"
                  clientAuth="false" sslProtocol="TLS" />
      -->
               <!-- Define an  AJP 1.3 Connector on port 8009 -->
      <Connector port="8109"   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="Standalone" defaultHost="localhost"   jvmRoute="jvm1">         
      --> 
      <Engine  name="Catalina" defaultHost="localhost" jvmRoute="tomcatA">
                 <!--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"/>
               
                 <!-- The  request dumper valve dumps useful debugging  information about
             the request  and response data received and sent by Tomcat.
              Documentation at: /docs/config/valve.html -->
        <!--
        <Valve   className="org.apache.catalina.valves.RequestDumperValve"/>
        -->
                 <!-- 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"/>
                 <!-- Define  the default virtual host
             Note: XML  Schema validation will not work with Xerces 2.2.
         -->
        <Host  name="localhost"   appBase="webapps"
               unpackWARs="true" autoDeploy="true"
               xmlValidation="false" xmlNamespaceAware="false">
                   <!--  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 -->
          <!--
          <Valve   className="org.apache.catalina.valves.AccessLogValve"  directory="logs"   
                  prefix="localhost_access_log." suffix=".txt"   pattern="common" resolveHosts="false"/>
          -->
                 </Host>
      </Engine>
    </Service>
  </Server>

2 Second tomcatB

         <!-- 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="8205" shutdown="SHUTDOWN">           
  <!--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"  />
    <!-- JMX Support  for the Tomcat server. Documentation at  /docs/non-existent.html -->
    <Listener   className="org.apache.catalina.mbeans.ServerLifecycleListener" />
    <Listener   className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"   />
             <!-- 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" />
    </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="8082"   protocol="HTTP/1.1" 
                  connectionTimeout="20000" 
                  redirectPort="8443" />
      <!-- 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 JSSE configuration, when using APR,  the 
           connector  should be using the OpenSSL style configuration
           described in  the APR documentation -->
      <!--
      <Connector  port="8443" protocol="HTTP/1.1" SSLEnabled="true"
                  maxThreads="150" scheme="https"  secure="true"
                  clientAuth="false" sslProtocol="TLS" />
      -->
               <!-- Define an  AJP 1.3 Connector on port 8009 -->
      <Connector port="8209"   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="Standalone" defaultHost="localhost"   jvmRoute="jvm1">         
      --> 
      <Engine  name="Catalina" defaultHost="localhost" jvmRoute="tomcatB">
                 <!--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"/>
               
                 <!-- The  request dumper valve dumps useful debugging  information about
             the request  and response data received and sent by Tomcat.
              Documentation at: /docs/config/valve.html -->
        <!--
        <Valve   className="org.apache.catalina.valves.RequestDumperValve"/>
        -->
                 <!-- 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"/>
                 <!-- Define  the default virtual host
             Note: XML  Schema validation will not work with Xerces 2.2.
         -->
        <Host  name="localhost"   appBase="webapps"
               unpackWARs="true" autoDeploy="true"
               xmlValidation="false" xmlNamespaceAware="false">
                   <!--  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 -->
          <!--
          <Valve   className="org.apache.catalina.valves.AccessLogValve"  directory="logs"   
                  prefix="localhost_access_log." suffix=".txt"   pattern="common" resolveHosts="false"/>
          -->
                 </Host>
      </Engine>
    </Service>
  </Server>

3 Third tomcatC

         <!-- 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="8305" shutdown="SHUTDOWN">           
  <!--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"  />
    <!-- JMX Support  for the Tomcat server. Documentation at  /docs/non-existent.html -->
    <Listener   className="org.apache.catalina.mbeans.ServerLifecycleListener" />
    <Listener   className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"   />
             <!-- 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" />
    </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="8083"   protocol="HTTP/1.1" 
                  connectionTimeout="20000" 
                  redirectPort="8443" />
      <!-- 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 JSSE configuration, when using APR,  the 
           connector  should be using the OpenSSL style configuration
           described in  the APR documentation -->
      <!--
      <Connector  port="8443" protocol="HTTP/1.1" SSLEnabled="true"
                  maxThreads="150" scheme="https"  secure="true"
                  clientAuth="false" sslProtocol="TLS" />
      -->
               <!-- Define an  AJP 1.3 Connector on port 8009 -->
      <Connector port="8309"   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="Standalone" defaultHost="localhost"   jvmRoute="jvm1">         
      --> 
      <Engine  name="Catalina" defaultHost="localhost" jvmRoute="tomcatC">
                 <!--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"/>
               
                 <!-- The  request dumper valve dumps useful debugging  information about
             the request  and response data received and sent by Tomcat.
              Documentation at: /docs/config/valve.html -->
        <!--
        <Valve   className="org.apache.catalina.valves.RequestDumperValve"/>
        -->
                 <!-- 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"/>
                 <!-- Define  the default virtual host
             Note: XML  Schema validation will not work with Xerces 2.2.
         -->
        <Host  name="localhost"   appBase="webapps"
               unpackWARs="true" autoDeploy="true"
               xmlValidation="false" xmlNamespaceAware="false">
                   <!--  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 -->
          <!--
          <Valve   className="org.apache.catalina.valves.AccessLogValve"  directory="logs"   
                  prefix="localhost_access_log." suffix=".txt"   pattern="common" resolveHosts="false"/>
          -->
                 </Host>
      </Engine>
    </Service>
  </Server>

Horizontal tomcat clustering or tomcat clustering on different machine system

If you want to do horizontal tomcat clustering then you don't need to change in ports
Just left ports unchanged e.g

1. <Server port="8005" shutdown="SHUTDOWN">
2. <Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
3. <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
4. Add jvmRoute
<Engine name="Catalina" defaultHost="localhost" jvmRoute="tomcatC">
5. Uncommented clustering tag
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpClu ster"/>

Add distributed tag in web.xml

Next step to do add distributed tag in web.xml to switching session among the tomcat clustering instance
Make any application, e.g we are making cluster as application folder in webapps
1. TomcatA - > webapps - > cluster -> WEB-INF -> web.xml
2. TomcatB - > webapps - > cluster -> WEB-INF -> web.xml
3. TomcatC - > webapps - > cluster -> WEB-INF -> web.xml
Add <distributable /> in all three web.xml file

         <?xml version="1.0"  encoding="ISO-8859-1"?>           
<web-app  xmlns="http://java.sun.com/xml/ns/javaee"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
      version="2.5">
    <distributable />
    
  </web-app>

Install mod_jk in module

Mod_jk is connector that communicates with apache web server and tomcat. We need to download and copy that connector in module folder of apache
http://tomcat.apache.org/connectors-doc/ we are using latest connector of mod_jk
Make mod_jk.log file in logs folder otherwise apache will throw error

Edit in httpd.conf

Open apache -> httpd.conf
Open in any text editor and add

         LoadModule  jk_module  modules/mod_jk-apache-2.2.4.so 
JkWorkersFile  "C:\cluster\Apache\conf\workers.properties" 
JkLogFile  "logs/mod_jk.log" 
JkLogLevel error 
JkMount /cluster  loadbalancer 
JkMount /cluster/* loadbalancer

Worker.properties file

Make a file with name of workers.properties in conf folder. This file tells properties of all tomcat instances. We have to specify all tomcat properties here. Apache will forword request to tomcat through this file

Vertical tomcat clustering this file like

 workers.tomcat_home=/tomcatA
    workers.java_home=$JAVA_HOME
    ps=/
    worker.list=tomcatA,tomcatB,tomcatC,loadbalancer   
 
   worker.tomcatA.port=8109
      worker.tomcatA.host=localhost
      worker.tomcatA.type=ajp13
      worker.tomcatA.lbfactor=1
    
   worker.tomcatB.port=8209
      worker.tomcatB.host=localhost
      worker.tomcatB.type=ajp13
      worker.tomcatB.lbfactor=1
   worker.tomcatC.port=8309
      worker.tomcatC.host=localhost
      worker.tomcatC.type=ajp13
      worker.tomcatC.lbfactor=1
   worker.loadbalancer.type=lb
      worker.loadbalancer.balanced_workers=tomcatA,tomcatB,tomcatC
      worker.loadbalancer.sticky_session=1

for horizontal tomcat clustering

 workers.tomcat_home=/tomcatA
    workers.java_home=$JAVA_HOME
    ps=/
    worker.list=tomcatA,tomcatB,tomcatC,loadbalancer   
 
   worker.tomcatA.port=8009
      worker.tomcatA.host=192.168.1.1
      worker.tomcatA.type=ajp13
      worker.tomcatA.lbfactor=1
    
   worker.tomcatB.port=8009
      worker.tomcatB.host=192.168.1.2
      worker.tomcatB.type=ajp13
      worker.tomcatB.lbfactor=1
   worker.tomcatC.port=8009
      worker.tomcatC.host=192.168.1.3
      worker.tomcatC.type=ajp13
      worker.tomcatC.lbfactor=1
   worker.loadbalancer.type=lb
      worker.loadbalancer.balanced_workers=tomcatA,tomcatB,tomcatC
      worker.loadbalancer.sticky_session=1

lbfactor properties define for load balancing factor, restrict number of request to send particular tomcat instance
e.g
worker.tomcatC.lbfactor=100
increase and decrease request to this tomcatC instance
Restart apache, tomcatA, tomcatB, tomcatC

Check clustering if apache start properly, It is fine without any errors otherwise check problems,basically mod_jk problems come. So download different mod_jk for your machine. Start all tomcats, tomcatA, tomcatB, and tomcatC. If all tomcats is started this means tomcat is working fine.
Open test.jsp on browser and check session id. Check which tomcat on test.jsp is running tomcatB or tomcatC. Close that tomcat, reload test.jsp. Check session id,if session id is same. Then tomcat clustering is working fine.

Test jsp file

Make test.jsp in cluster folder of webapps
tomcatA

 <%
   session.setAttribute("a","a");
%>
<html>
<head>
<title>Test  JSP</title>
</head>   
<body>
  <table  width="100%" border="0" cellspacing="0"   cellpadding="0">
    <tr bgcolor="#CCCCCC">
      <td width="13%">TomcatA  Machine</td>
      <td  width="87%">&nbsp;</td>
    </tr>
    <tr>
      <td>Session ID :</td>
       <td><%=session.getId()%></td>
    </tr>
  </table>
  </body>
  </html>

tomcatB

 <%
   session.setAttribute("a","a");
%>
<html>
<head>
<title>Test  JSP</title>
</head>   
<body>
  <table  width="100%" border="0" cellspacing="0"   cellpadding="0">
    <tr bgcolor="#CCCC00">
      <td width="13%">TomcatB  Machine</td>
      <td  width="87%">&nbsp;</td>
    </tr>
    <tr>
      <td>Session ID :</td>
       <td><%=session.getId()%></td>
    </tr>
  </table>
  </body>
   </html>

TomcatC

   <%
   session.setAttribute("a","a");
%>
<html>
<head>
<title>Test JSP</title>
</head>   
<body>
  <table width="100%" border="0"  cellspacing="0" cellpadding="0">
    <tr  bgcolor="#00CCCC">
      <td  width="13%">TomcatC Machine</td>
      <td  width="87%">&nbsp;</td>
    </tr>
    <tr>
      <td>Session  ID :</td>
       <td><%=session.getId()%></td>
    </tr>
  </table>
  </body>
   </html>

Download pre build load balancing, tomcat clustering code.



Nguon: http://www.easywayserver.com/impleme...e-Installation

Thao khao: http://onjava.com/pub/a/onjava/2004/...ng.html?page=2

http://tomcat.apache.org/tomcat-5.5-...ter-howto.html