Tomcat 架构分析(五) 核心Catalina模块
Tomcat 架构分析(五) 核心Catalina模块前言： 这个子模块包含了所有以org.apache.catalina开头的java源代码。该子模块的任务是规范了Tomcat的总体架构，定义了Server、Service、Host、Connector、Context、Session及Cluster等关键组件及这些组件的实现，这个子模块大量运用了Co
·
Tomcat 架构分析(五) 核心
Catalina模块
前言：
这个子模块包含了所有以org.apache.catalina开头的java源代码。该子模块的任务是规范了Tomcat的总体架构，定义了Server、Service、Host、Connector、Context、Session及Cluster等关键组件及这些组件的实现，这个子模块大量运用了Composite设计模式。同时也规范了Catalina的启动及停止等事件的执行流程。
Catalina's Configuration Files
Catalina's default behavior can be directly configured by editing the six configuration files located in Tomcat's "$CATALINA_BASE/conf" directory. Here's an overview of the files located in this directory and the kinds of options that can be configured within each.
catalina.policy
This file contains the
Tomcat security
policy for the Catalina Java class, expressed in standard Security Policy syntax, as defined in the JEE specification. This is Tomcat's core security policy, and includes permissions definitions for system code, web applications, and Catalina itself.
catalina.properties
This file is a standard Java properties file for the Catalina class. It contains information such as security package lists and class loader paths. This file can also contains some String cache settings, that you might edit when tuning your server for best
Tomcat performance
.
logging.properties
This file configures the way that Catalina's built-in
logging
functions, including things such as threshold and log location. Note that all the entries in this log refer to JULI, the modified commons-logging implementation that Tomcat automatically uses in place of your JDK's logging implementation.
content.xml
This XML configuration file is used to define
Tomcat Context
information that will be loaded for every web application running on a given instance of Tomcat. In general, you should configure your Context information elsewhere, but there are a few entries in this file that can be uncommented to alter the way that Tomcat handles session persistence and Comet connections.
server.xml
This is
Tomcat's main
configuration
file
, which uses the hierarchical syntax specified in the Java Servlet specification to configure Catalina's initial state, as well as define the order in which Tomcat boots and builds its various components. This file is quite complex, but comprehensive documentation is available on the Apache website.
tomcat-users.xml
This file contains information about the various users, passwords, and user roles on a given Tomcat server, as well as information about trusted Realms (JNDI,
JDBC
, etc.) where this data can be accessed.
web.xml
This file configures options and values that will be applied to all applications loaded into a given instance of Tomcat, including
servlet
definitions such as buffer sizes, debugging levels, Jasper options like
classpath
, MIME types, and default welcome files for directories that do not have their own "index" files. Although you can technically configure options for specific web applications in this file, this will require you to restart your entire server to propagate these changes, so it is not recommended.
Rotating Catalina.out
A common question asked by Tomcat beginners is how to rotate the Catalina.out log file, without restarting Tomcat. (If you're not familiar with the file, Catalina.out is the standard destination log file for System.out and System.err,
JVM
loggers that print information about fatal errors in the JVM.)
There are two answers.
The first, which is more direct, is that you can rotate Catalina.out by adding a simple pipe to the log rotation tool of your choice in Catalina's startup shell script. This will look something like:
"$CATALINA_BASE"/logs/catalina.out WeaponOfChoice 2>&1 &
Simply replace "WeaponOfChoice" with your favorite log rotation tool.
The second answer is less direct, but ultimately better. The best way to handle the rotation of Catalina.out is to make sure it never needs to rotate. Simply set the "swallowOutput" property to true for all Contexts in "server.xml".
This will route System.err and System.out to whatever Logging implementation you have configured, or JULI, if you haven't configured it. All commons-logger implementations rotate logs by default, so rotating Catalina.out is no longer your problem.
For more information about JULI, Log4J, and Tomcat logging in general, check out our easy-to-follow guide to
Tomcat Logging
.
Managing Catalina as an MBean
Because Catalina is a Java class, if you enable Java Management Extentions (
JMX
) management, you can actually manage all of Catalina's exposed functions as a single MBean, and reference all its hierarchical elements by name. Apache maintains a list of all the MBean names as part of the Tomcat documentation.
In order to begin managing Catalina as an MBean, all you need to do is modify the CATALINA_OPTS system variable to allow JMX access.
For a comprehensive, step by step guide to enabling and using JMX with Catalina, check out our guide to
Tomcat JMX
!
Learn More About Catalina
If you want to learn more about the Catalina servlet container, there are a number of resources you can consult. Here are some of our favorite Tomcat Catalina resources:
Understanding Apache Tomcat
- MuleSoft's comprehensive guide to Apache Tomcat, including FAQs, HOW-TO's, whitepapers, and more.
The Tomcat API
- Apache's documentation of the Tomcat API, with detailed information about each package and its contained elements.
The Java Servlet Specification
- Information on the Servlet specification that Catalina implements.
The Tomcat Mailing Lists
- User and Developer Discussions about Tomcat-related topics hosted on the Apache Website.
瓜分20万奖金 获得内推名额 丰厚实物奖励 易参与易上手
更多推荐
0
0- 0
已为社区贡献1条内容
所有评论(0)