Servlet学习（五）：ServletConfig类的作用

package demo01;
import javax.servlet.*;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
public class Hello implements Servlet {
    public Hello() {
    }
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
//        ServletConfig的作用：
//        1、可以获取Servlet程序的别名servlet-name的值
        System.out.println("Hello的别名是"+servletConfig.getServletName());
//        2、获取初始化参数init-param
        System.out.println("初始化参数username的值："+servletConfig.getInitParameter("username"));
        System.out.println("初始化参数url的值："+servletConfig.getInitParameter("url"));
//        3、获取ServletContext对象
        System.out.println(servletConfig.getServletContext());
    }
    @Override
    public ServletConfig getServletConfig() {
        return null;
    }
    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException { 
    }
    @Override
    public String getServletInfo() {
        return null;
    }
    @Override
    public void destroy() {
    }
}