Struts2 Performance Tuning（性能调优）

 Performance tuning

The following are some tips and tricks to squeeze the most performance out of Struts 2.

Turn off logging and devMode.（关闭logging和devMode）

DevMode allows reloading of configuration and validation related files, but because they happen on each request, this setting will totally kill your performance.
When using logging, make sure to turn off logging (esp. Freemarker generates a LOT of logging), and check if a level is enabled before printing it, or you will get the cost of the String parsing/concatination anyways.

Do not use interceptors you do not need.（不要使用你不需要的拦截器）

If you do not require a full stack of interceptors for an Action, then try using a different one (basicStack), or remove interceptors you do not need.

 

 

Use the correct HTTP headers (Cache-Control & Expires).（使用正确的HTTP头（缓存控制和过期时间））

When returning HTML views, make sure to add the correct headers so browsers know how to cache them.

 

 

Copy the static content from the Struts 2 jar when using the Ajax theme (Dojo) or the Calendar tag.（当使用AJAX theme（Dojo）或日历tag时，从Struts2的jar包复制静态内容到http服务器）

Struts 2 uses some external javascript libraries and cascading stylesheets for certain themes and tags. These by default are located inside the Struts 2 jar, and a special filter returns them when requesting a special path (/struts). Although Struts 2 can handle these requests, an application/servlet container is not optimized for these kind of requests. Consider moving these .js and .css files to a seperated server (Lighttpd, Apache HTTPD, ..).

Create a freemarker.properties file in your WEB-INF/classes directory.（在WEB-INF/classes目录，新建一个freemarker.properties文件）

Create the freemarker.properties file and add the following setting (or whatever value you deem fitting):

template_update_delay=60000

This value determines how often Freemarker checks if it needs to reloads the templates from disk. The default value is 500 ms. Since there is no reason to check if a template needs reloading, it is best to set this to a very large value. Note that this value is in seconds and freemarker will convert this value to milliseconds.

See also: Freemarker configuration properties

Enable Freemarker template caching（激活Freemarker模板的缓存）

As of Struts 2.0.10, setting the property struts.freemarker.templatesCache to true will enable the Struts internal caching of Freemarker templates. This property is set to false by default.

In Struts versions prior to 2.0.10, you had to copy the /template directory from the Struts 2 jar in your WEB_APP root to utilize Freemarker's built in chaching mechanism in order to achieve similar results.

The built in Freemarker caching mechanism fails to properly cache templates when they are retrieved from the classpath. Copying them to the WEB_APP root allows Freemarker to cache them correctly. Freemarker looks at the last modified time of the template to determine if it needs to reload the templates. Resources retrieved from the classpath have no last modified time, so Freemarker will reload them on every request.

When overriding a theme, copy all necessary templates to the theme directory.（当覆盖一个theme时，copy所有重要的模板到theme目录
）

There's a performance cost when a template cannot be found in the current directory. The reason for this is that Struts 2 must check for a template in the current theme first before falling back to the parent theme. In the future, this penalty could be eliminated by implementing a missing template cache in Struts 2.

Do not create sessions unless you need them.（在你需要的时候才创建sessions ）

Struts 2 does not create sessions unless asked to (for example, by having the createSession interceptor in your interceptor stack). Note that when you use SiteMesh however, a session will always be created (See http://forums.opensymphony.com/thread.jspa?messageID=5688 for details).

When using Freemarker, try to use the Freemarker equivalent rather than using the JSP tags.（当使用FreeMarker时，尽量使用等价的FreeMarker元素，代替JSP的标签）

Freemarker has support for iterating lists, displaying properties, including other templates, macro's, and so on. There is a small performance cost when using the S2 tags instead of the Freemarker equivalent (eg. <s:property value="foo"/> should be replaced by ${foo}).

 

引自http://wangrui.iteye.com/blog/153769

http://struts.apache.org/2.0.11/docs/performance-tuning.html

评论

1 楼 zfyyfz 2008-06-23  

很好 ； 在开发时千万别 template_update_delay=60000
否则每次 改动页面时都得重起服务器 ；