public abstract class MyGenericServlet implements Servlet, ServletConfig {
    private ServletConfig servletConfig;
    @Override
	public void init(ServletConfig servletConfig) throws ServletException {
		// TODO Auto-generated method stub
		this.servletConfig = servletConfig;
	}
    ......
}
- - -
public class LoginServlet extends MyGenericServlet {
    public void init() throws ServletException {
        System.out.println("初始化");
        init(); // 记得初始化
    }
}