Head First Servlets & JSP Study Notes Chapter 11 - Web Application Deployment

jar：java archive（java归档）

war: w eb ar chive (web archive)

A war file is just a snapshot of the structure of a web application, in a more portable compressed form (it's actually a jar file). To create a war file is to compress the entire Web application structure (not the Web application name directory, that is, compress from the WEB-INF level).

In the Tomcat container, the filename of the war file becomes the name of the web application.

Configure the welcome file in web.xml:

1 <web-app>
2     <welcome-file-list>
3         <welcome-file>index.html</welcome-file>
4         <welcome-file>default.jsp</welcom-file>　　//<welcome-file>中的文件不以斜线开头
5     </welcom-file-list>
6 </web-app>

Configure the error page in web.xml:

1  < web-app > 
2      < error-page > 
3          < exception-type > java.lang.Throwable </ exception-type >　　// Except for the specific errors below, other errors use this errorPage.jsp page
 4          < location > /errorPage.jsp </ location > 
5      </ error-page > 
6      
7      < error-page > 
8          < exception-type > java.lang.ArithmeticException </ exception-type >　　//<exception-type>
Must use fully qualified class name9         <location>/arithmeticError.jsp</location>
10     </error-page>
11     
12     <error-page>
13         <error-code>404</error-code>　　//指定错误码
14         <location>/notFoundError.jsp</location>
15     </error-page>
16 </web-app>

Configure Servlet initialization in web.xml:

Use the <load-on-startup> element in DD if you want the servlet to be loaded at deployment time (or when the server restarts), rather than waiting until the first request arrives.

1  < servlet > 
2      < servlet-name > KathyOne </ servlet-name > 
3      < servlet-class > foo.DeployTestOne </ servlet-class > 
4      < load-on-startup > 1 </ load-on-startup > / A value greater than 0 for /<load-on-startup> indicates that the servlet should be initialized when the application is deployed (or when the server is restarted). 
The smaller the value, the earlier the initialization, e.g. <load-on-startup>1</load-on-startup> is initialized 5  earlier than <load-on-startup>5</load-on-startup> </ servlet >