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Tomcat configuration techniques

Tomcat configuration problems

Tomcat configuration techniques

Q: How can I register a specific domain in Tomcat?

A: To register a specific domain name for your Tomcat server you should replace the "defaultHost" attribute in the <Engine> element of your server.xml configuration and update the <Host> element's name attribute to match, as in the code sample below.

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How can I register a specific domain in Tomcat?

Q: How can I move my Web applications outside the Tomcat directory?

A: Your suggestion is a sensible one, since it helps separate the fairly static server installation from frequently changing application resources, and makes the server less prone to accidental damage.

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How can I move my Web applications outside the Tomcat directory?

Q: How many connections can be made to Tomcat on Windows?

A: The number of connections accepted by Tomcat is determined by the <Connector> elements in the server.xml configuration file. The maxProcessors attribute sets the total number of threads that can run simultaneously and the acceptCount attribute controls the number of requests that may be queued waiting for a connection.

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How many connections can be made to Tomcat on Windows?

Q: Can Tomcat call a servlet automatically using the <run-at> tag?

A: Tomcat does not support a <run-at> element, it is not part of the servlet specification. This feature is a custom extension of the Resin servlet container.

You may be able to achieve similar results using independent scheduling programs such as cron and uschedule.

Tomcat configuration problems

Q: Tomcat doesn't find my global initialization parameters!

A: Global initialisation parameters set using context-param elements can only be accessed through the Web application's ServletContext object in Tomcat, not via the ServletConfig object's getInitParameter method.

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Tomcat doesn't find my global initialization parameters!

Q: Why does the server fail to load the supporting class for my servlet?

A: Tomcat only loads supporting classes from specific directories in the server and application directory structure, not from the system classpath, so your library files must be in the wrong place. The three key locations are...

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Why does the server fail to load the supporting class for my servlet?

Q: All my JSP give a 404 error!

A: If static files are being served but JSP documents are not, first check the Web application directory where the JSP source should be deployed. In a default Tomcat installation this will be under the directory $CATALINA_HOME/webapps. Use the Host appBase attribute in your server.xml file to help locate the specific directory.

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All my JSP give a 404 error!

Q: I get a "Page cannot be displayed" error!

A: You should look at your server logs to see how your request was recorded. It is very difficult to guess what the problem might be without seeing your set-up but check you have a servlet mapping that matches the referring URL in your HTML or JSP document, something like this...

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I get a "Page cannot be displayed" error!

Q: I cannot generate tomcat-apache.conf, how come?

A: The tomcat-apache.conf file is created automatically when the Tomcat version 3 server process starts. Are you working with the version 3 architecture? If the server is not starting, go back and check through the Tomcat configuration points step by step, these are the most fundamental ones.

Q: I get NoClassDefFoundError for ELResolver with Tomcat 6!

A: Tomcat 6 implements the Java Server Pages 2.1 specification, in which the ELResolver class is moved to a more general javax.el package. If your servlet or other packages in your application, such as Java Server Faces or Java Standard Tag Library classes, reference the original package location at javax.servlet.jsp.el, they will need to be updated to compatible versions.

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