windows下Tomcat配置多实例

详情参见tomcat安装目录下RUNNING.txt中Advanced Configuration - Multiple Tomcat Instances部分。

问题源于下面这段tomcat官方文档的介绍：

Throughout the docs, you'll notice there are numerous references to $CATALINA_HOME. This represents the root of your Tomcat installation. When we say, "This information can be found in your $CATALINA_HOME/README.txt file" we mean to look at the README.txt file at the root of your Tomcat install. Optionally, Tomcat may be configured for multiple instances by defining $CATALINA_BASE for each instance. If multiple instances are not configured, $CATALINA_BASE is the same as $CATALINA_HOME.

These are some of the key tomcat directories:

• /bin - Startup, shutdown, and other scripts. The *.sh files (for Unix systems) are functional duplicates of the *.bat files (for Windows systems). Since the Win32 command-line lacks certain functionality, there are some additional files in here.
• /conf - Configuration files and related DTDs. The most important file in here is server.xml. It is the main configuration file for the container.
• /logs - Log files are here by default.
• /webapps - This is where your webapps go.

主要介绍了$CATALINA_HOME和$CATALINA_BASE的区别，这里讲如果要配置多实例，应该对$CATALINA_BASE进行配置。
由于默认情况下，一般只会使用tomcat的一个实例，所以平时很少用到$CATALINA_BASE配置的方式。
以前要配置多个tomcat时，会解压多个tomcat程序，修改端口后分别启动，相对会占用较多的存储空间。
本文的配置方式是实现在只用一个tomcat程序的情况下，启动多个实例。

1、原理：
在tomcat的安装目录中，所有实例共享的文件夹只有lib、bin两个文件夹，其余的文件夹每个实例分别持有一份。由于一般只有一个实例，所以这些文件夹放在了同一目录下，目录结构如下：

若要实现多实例，目录结构如下所示：

上图中定义了2个实例。

2、步骤二：在instance1和instance2下分别增加一个自定义的startup.bat文件，内容如下

@echo off

@echo 删除缓存
rmdir /S/Q %CD%/work

SET CATALINA_BASE=%CD%

cd ../../bin
catalina.bat start

前提是已经定义了系统变量JAVA_HOME，并且已经添加到PATH中
此处可根据需要设置CATALINA_OPTS和JAVA_OPTS环境变量。

3、注意事项：
为了保证端口不冲突，需要分别设置各个实例下conf/server.xml中的端口，避免重复，否则启动多个时会出现jvm_bind异常。
4、启动：
分别双击instances/instance1/startup.bat和instances/instance1/startup.bat，就启动了2个实例，由于我设定的端口分别为8080和8081，
分别访问http://localhost:8080和http://localhost:8081即可分别访问，对应的部署不作赘述。