zoukankan      html  css  js  c++  java
  • Servlet创建的三种方式

    关于servlet的创建,我们有三种方式。

    • 实现Servlet接口

    • 继承GenericServlet

    • 继承HttpServlet

    1 实现Servlet接口

    实现五个抽象方法

    package com.zjw;
    
    import javax.servlet.*;
    import java.io.IOException;
    
    public class MyServlet implements Servlet {
    
        public MyServlet() {
            System.out.println("MyServlet构造方法....");
        }
    
        @Override
        public void init(ServletConfig config) throws ServletException {
            System.out.println("init....");
        }
    
        @Override
        public ServletConfig getServletConfig() {
            System.out.println("getServletConfig....");
            return null;
        }
    
        @Override
        public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
            System.out.println("service....");
        }
    
        @Override
        public String getServletInfo() {
            System.out.println("getServletInfo....");
            return null;
        }
    
        @Override
        public void destroy() {
            System.out.println("destroy....");
        }
    }
    

    2 继承GenericServlet

    实现service抽象方法

    package com.zjw;
    
    import javax.servlet.GenericServlet;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import java.io.IOException;
    
    public class GenServlet extends GenericServlet {
        @Override
        public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
            System.out.println("哈哈哈");
        }
    }
    
    

    3 继承HttpServlet

    需要重写doGet、doPost方法,否则请求不被允许。

    package com.zjw;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    public class HttpsServlet extends HttpServlet {
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            System.out.println("这个是get请求");
        }
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            System.out.println("这个是post请求");
        }
    }
    
    

    4 web.xml配置

    <?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
             version="4.0">
        <servlet>
            <servlet-name>my</servlet-name>
            <servlet-class>com.zjw.MyServlet</servlet-class>
        </servlet>
        <servlet>
            <servlet-name>gs</servlet-name>
            <servlet-class>com.zjw.GenServlet</servlet-class>
        </servlet>
        <servlet>
            <servlet-name>hs</servlet-name>
            <servlet-class>com.zjw.HttpsServlet</servlet-class>
        </servlet>
        <servlet-mapping>
            <servlet-name>my</servlet-name>
            <url-pattern>/myservlet</url-pattern>
        </servlet-mapping>
        <servlet-mapping>
            <servlet-name>gs</servlet-name>
            <url-pattern>/gs</url-pattern>
        </servlet-mapping>
        <servlet-mapping>
            <servlet-name>hs</servlet-name>
            <url-pattern>/hs</url-pattern>
        </servlet-mapping>
    </web-app>
    
    --------------- 我每一次回头,都感觉自己不够努力,所以我不再回头。 ---------------
  • 相关阅读:
    CF 142B Tprimes
    CF 231A Team
    poj 2001 Shortest Prefixes ——字典树入门
    hdu 1039 Easier Done Than Said?
    poj 2528 Mayor's posters
    hdu 1061 Rightmost Digit
    poj 2503 Babelfish
    CF271 A. Beautiful Year
    poj 2752
    CF271 B. Prime Matrix
  • 原文地址:https://www.cnblogs.com/zjw-blog/p/13890534.html
Copyright © 2011-2022 走看看