Shulou(Shulou.com)06/02 Report--

This article will explain in detail how to clean up the cache in Tomcat. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

I. introduction to Tomcat "caching"

Many times people like to call the things in tomcat's work directory cache, in fact, that is not very appropriate. Work directory is only the working directory of tomcat, that is, the working directory where tomcat converts jsp into class files, which is why it is called work directory instead of cache directory. How jsp,tomcat works is that when a browser visits a jsp page, tomcat converts the jsp page into a .java file in the work directory, such as converting index.jsp into an index_jsp.java file, then compiling it into an index_jsp.class file, and finally the tomcat container loads the index_jsp.class class into memory through the ClassLoader class to respond to the client's work.

Tomcat will regularly trace the jsp file in the container and read the properties of each file. When it is found that a jsp file has changed (the last modification time of the file is not the same as the last time), tomcat will reconvert and compile the jsp file. But tomcat sketches are timed, not real-time, which is why it takes a few minutes for the modified jsp to take effect after the jsp file is modified. Of course, in order to take effect immediately, many seniors would suggest that the files in the work directory be removed immediately after modifying the jsp page.

In addition, in the tomcat container, the maximum compilation of converted java files (such as index_jsp.java) is 64k, so when jsp in other containers is migrated to tomcat containers, large jsp files will fail to compile, so it is recommended that the business logic in jsp be written into a separate class and executed by calling the static method of this class in jsp. Extract the js from the jsp page and put it into a separate js file.

II. Clean-up of Tomcat "cache"

Since many times we want to take effect immediately after changing the content of jsp, we naturally don't want to wait a few minutes for tomcat to refresh automatically (according to my past experience, in most cases it can take effect immediately). So here are three ways to clean up:

Method 1:

Conf/server.xml file

Add reloadable= "true" in the middle of Context path

For example:

Method 2:

Delete cache files in the work directory

You can delete the Catalina directory

Note: the entire directory of work cannot be deleted, otherwise conf/web.xml will be deleted when tomcat is restarted, so that when starting, the log will prompt: No Default web.xml, and the access page will show a 404 error.

Method 3:

Add the following code to the top of the jsp page so that the jsp can be loaded in real time, and each visit will re-convert the jsp page into a .java file.

This is the end of the article on "how to clean the cache in Tomcat". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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