第三课ServletConfig对象

servletconfig：封装了servlet的配置信息，并且可以获取servletcontext对象。

1、配置servlet的初始化参数：

<servlet>

         <servlet-name>helloServlet</servlet-name>

         <servlet-class>com.atgaozhen.servlet.HelloServlet</servlet-class>

         <init-param>
        <param-name>user</param-name>
        <param-value>root</param-value>

         </init-param>

         <init-param>
        <param-name>password</param-name>
        <param-value>root</param-value>

         </init-param>

         <load-on-startup>1</load-on-startup>

</servlet>

2、获取初始化参数：getInitParameter(String name)

获取指定参数名的初始化参数

javax.servlet

Interface ServletConfig

String	getInitParameter(String name)           Returns a String containing the value of the named initialization parameter, or null if the parameter does not exist.
Enumeration	getInitParameterNames()           Returns the names of the servlet's initialization parameters as an Enumeration of String objects, or an empty Enumeration if the servlet has no initialization parameters.
ServletContext	getServletContext()           Returns a reference to the ServletContext in which the caller is executing.
String	getServletName()           Returns the name of this servlet instance.

方法实例：

@Override
public void init(ServletConfig servletConfig) throws ServletException {
System.out.println("init(ServletConfig arg0)");
   String user=servletConfig.getInitParameter("user");
   System.out.println("user:"+user);
   
   Enumeration<String>names=servletConfig.getInitParameterNames();
   while(names.hasMoreElements()){
    String name=names.nextElement();
    String value=servletConfig.getInitParameter(name);
    System.out.println("name:"+name+":"+value);
   }
}

 System.out.println(servletConfig.getServletName());(不是很重要)