public
class TestLifeCycleServlet
extends HttpServlet {
public TestLifeCycleServlet(){
System.out.println( "constructor");
}
@Override
public void destroy() {
System.out.println( "destroy");
}
@Override
public void init(ServletConfig config) throws ServletException {
System.out.println( "init");
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
System.out.println( "doGet");
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
public TestLifeCycleServlet(){
System.out.println( "constructor");
}
@Override
public void destroy() {
System.out.println( "destroy");
}
@Override
public void init(ServletConfig config) throws ServletException {
System.out.println( "init");
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
System.out.println( "doGet");
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
<
servlet
>
< servlet-name >testlife </ servlet-name >
< servlet-class >
com.dvnchina.test.TestLifeCycleServlet
</ servlet-class >
</ servlet >
< servlet-mapping >
< servlet-name >testlife </ servlet-name >
< url-pattern >/testlife </ url-pattern >
</ servlet-mapping >
< servlet-name >testlife </ servlet-name >
< servlet-class >
com.dvnchina.test.TestLifeCycleServlet
</ servlet-class >
</ servlet >
< servlet-mapping >
< servlet-name >testlife </ servlet-name >
< url-pattern >/testlife </ url-pattern >
</ servlet-mapping >
constructor
init
doGet
doGet
doGet
destroy
现在分析一下这个结果。
从例子可以看出servlet的生命周期为：
实例化->初始化(init)->调用实例doGet方法->销毁(destroy)
并且我们访问了3次servlet，而构造函数，init()方法，destroy()方法都只调用了一次，这说明只实例化了一次servlet。servle容器对于一个servlet只管理一个实例，每次客户端对这个servlet发送请求时，都是调用这个servlet的实例。
本文转自 yzzh9 51CTO博客，原文链接：http://blog.51cto.com/java999/163702，如需转载请自行联系原作者
