关于servlet的初始化

我看书上说:Servlet只会初始化一次,在初始化的时候容器为servlet建立了ServletConfig和ServletContext。容器去web.xml中读取初始化参数,将初始化参数传递给ServletConfig和ServletContext,然后再将ServletConfig和ServletContext传递给servlet的init()方法。
假如现在有一个email项目,然后里面有一个WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
    xmlns="http://java.sun.com/xml/ns/j2ee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>email</servlet-name>
    <servlet-class>Email</servlet-class>
     <init-param>
    <param-name>myEmail</param-name>
    <param-value>Emi.wan@xxx.com</param-value>
    </init-param>
    
    <init-param>
    <param-name>adminEmail</param-name>
    <param-value>Admin@xxx.com</param-value>
    </init-param>
  </servlet>
  
    <servlet-mapping>
    <servlet-name>email</servlet-name>
    <url-pattern>/email.do</url-pattern>
   
  </servlet-mapping>

<context-param>
<param-name>managerEmail</param-name>
<param-value>David.tang@xxx.com</param-value>
</context-param>
</web-app>

 

然后一个servlet----Email.java

public class Email extends HttpServlet {

    
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("My Email is "+getServletConfig().getInitParameter("myEmail")+"<br>");
        out.println("Admin\'s Email is "+getServletConfig().getInitParameter("adminEmail")+"<br>");
        out.println("Manager\'s Email is "+getServletContext().getInitParameter("managerEmail")+"<br>");
    }

    
}

 

如果我修改了web.xml中

<init-param>和<context-param>的<param-value>值,书上说只能项目重部署的时候才能看见这个改变,可是我直接刷新几次网页(强调:一定要是几次)就看到改动的值了,不明白为什么,难道不用重部署,servlet也可以再次初始化,再次去读web.xml的初始化参数吗??我是用的MyEclipse+apache_tomcat5.5.27开发的。

   

eclipse里,你只改要代码或配置文件,然后保存,它会自动编译的,会重新启动tomcat的,不信,你保存好,注意看一下,eclipse里的控制台,肯定会有重启信息的

那是因为你是用MyEclipse去部署工程的,如果你打个war包放到tomcat下的话, 就不可能这个样子了,

工具隐藏了细节...

Tomcat配置文件..TOMCAT_HOME\conf\server.xml中在之间如果
[code="xml"][/code]中有reloadable="true"那么改变的类是可以即时编译加载的,如果不想即时加载就将其置成false。

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