常用方法

public class MyServlet extends HttpServlet {

    private ServletConfig config;

    // 定义一个config成员变量，利用servlet的初始化方法，对config赋值
    @Override
    public void init(ServletConfig config) throws ServletException {
        this.config = config;
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // config的常用方法
        // 1、根据key获取value
        String parameter = config.getInitParameter("encoding");
        System.out.println(parameter);

        // 2、获取所有key
        Enumeration<String> keys = config.getInitParameterNames();
        while (keys.hasMoreElements()) {
            // 获取每一个key
            String key = keys.nextElement();
            String value = config.getInitParameter(key);
            System.out.println(key + ":" + value);
        }

        // 3、获取Servlet的名称
        String servletName = config.getServletName();
        System.out.println(servletName);

        // 4、获取ServletContext对象
        ServletContext servletContext = config.getServletContext();
        System.out.println(servletContext);
        
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }

}

<servlet>
        <servlet-name>myServlet</servlet-name>
        <servlet-class>com.hw.web.MyServlet</servlet-class>
        <!-- 配置servletconfig -->
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>myServlet</servlet-name>
        <url-pattern>/myServlet</url-pattern>
    </servlet-mapping>