Servlet配置load-on-startup

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns="http://java.sun.com/xml/ns/javaee" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" 
metadata-complete="true" version="3.0">
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <!--
  Element : load-on-startup
	The load-on-startup element indicates that this servlet should be 
 loaded (instantiated and have its init() called)on the startup of the 
 web application. 
 (这句话的含义是说假设设置了这个元素的值，那么在web应用程序启动的时候，会实例化这个servlet
 而且调用当中的init方法) 
 The optional contents of these element must be 
 an integer indicating the order in which the servlet should be 
 loaded. If the value is a negative integer, or the element is not 
 present, the container is free to load the servlet whenever it 
 chooses. If the value is a positive integer or 0, the container must 
 load and initialize the servlet as the application is deployed. The 
 container must guarantee that servlets marked with lower integers 
 are loaded before servlets marked with higher integers.
 (上面的含义表示假设负数或没有当前的值设置，则某个servlet不管何时在被选择的时候才载入，包含上面的
 instantiated和init)
 The container may choose the order of loading of servlets with the 
 same load-on-start-up value.(容器能够选择一个同样的value去载入servlet)

Data Type : load-on-startupType
Enumerated Values :  
   -->
  <servlet>
    <servlet-name>HelloworldServlet</servlet-name>
    <servlet-class>com.ghsy.HelloworldServlet</servlet-class>
    <load-on-startup>2</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>HelloworldServlet</servlet-name>
    <url-pattern>/Helloworld</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>LifecycleServlet</servlet-name>
    <servlet-class>com.ghsy.LifecycleServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>LifecycleServlet</servlet-name>
    <url-pattern>/lifecycle</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>InitServlet</servlet-name>
    <servlet-class>com.ghsy.InitServlet</servlet-class>
    <init-param>
      <param-name>參数1</param-name>
      <param-value>value1</param-value>
    </init-param>
    <init-param>
      <param-name>參数2</param-name>
      <param-value>value2</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>InitServlet</servlet-name>
    <url-pattern>/init</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>GenericServletDemo</servlet-name>
    <servlet-class>com.ghsy.GenericServletDemo</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>GenericServletDemo</servlet-name>
    <url-pattern>/generic</url-pattern>
  </servlet-mapping>
</web-app>