Servlet回顾

1.新建一个Maven工程当做父工程。添加pom依赖。删去src目录。

pom依赖：

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.15</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    </dependencies>

2. 建立一个Moudle：springmvc-01-servlet

3.添加Web app的支持

 <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
    </dependencies>

4.编写一个Servlet类，用来处理用户的请求

package com.kuang.servlet;

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 HelloServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取前端参数
        String method = req.getParameter("method");
        if (method.equals("add")){
            req.getSession().setAttribute("msg","use add method");
        }
        if (method.equals("delete")){
            req.getSession().setAttribute("msg","use delete method");
        }
        //调用业务层
        //视图转发或重定向
        req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req,resp);
    }

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

5.编写Hello.jsp，在WEB-INF目录下新建一个jsp的文件夹，新建hello.jsp

<%--
  Created by IntelliJ IDEA.
  User: 临易
  Date: 2022/2/17
  Time: 10:24
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

${msg}

</body>
</html>

6.在web.xml中注册Servlet

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd"
         version="5.0">

    <servlet>
        <servlet-name>hello</servlet-name>
        <servlet-class>com.kuang.servlet.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>hello</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>

<!--    设置超时时间-->
<!--    <session-config>-->
<!--        <session-timeout>15</session-timeout>-->
<!--    </session-config>-->

<!--    设置欢迎页-->
<!--    <welcome-file-list>-->
<!--        <welcome-file>index.jsp</welcome-file>-->
<!--    </welcome-file-list>-->
    
</web-app>

7. 创建表单form.jsp

<%--
  Created by IntelliJ IDEA.
  User: 临易
  Date: 2022/2/17
  Time: 10:34
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

<form action="/hello" method="post">
    <input type="text" name="method">
    <input type="submit">
</form>

</body>
</html>