原文:
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. 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. The container may choose the order of loading of servlets with the same load-on-start-up value.
译文:
load-on-startup 这个元素的含义是在服务器启动的时候就加载这个servlet(实例化并调用init()方法).这个元素中的可选内容必须为一个整数,表明了这个servlet被加载的先后顺序.当是一个负数时或者没有指定时，则表示服务器在该servlet被调用时才加载。当值为0或者大于0时，表示服务器在启动时就加载这个servlet.该容器肯定可以保证被标记为更小的整数的servlet比被标记为更大的整数的servlet更先被调用,还可已选择同样的load-on-start-up值来夹在servlets.
补充:正数的值越小，启动该servlet的优先级越高。