spring MVC

狂神说springMVC笔记

回顾MVC架构

MVC架构

MVC是一种架构模式，主要作用是降低了视图与业务逻辑间的双向耦合

==模型model、视图view、控制器controller==缩写

model：数据模型，，一般分为数据层（dao层）和服务层（service层）调用dao层执行业务
view：负责模型的展示，即前端页面
controller：接收用户请求，交给模型处理，处理完将模型数据交给视图，由视图负责展示。控制器的任务就是在视图展示和模型处理之间进行调度

最经典的MVC架构

JSP+Servlet+JavaBean

参考文章

SpringMVC学前回顾

回顾servlet

1. 新建maven项目，导入pom依赖

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.1.9.RELEASE</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.创建module：springMVC-01-servlet

右键添加Framework支持

选择web application

3.pom.xml导入servlet 和 jsp 的 jar 依赖

<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>

4.编写servlet类`HelloServelt`，处理用户的请求

public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取前端参数
            String method = req.getParameter("method");
            if (method.equals("add")){
                req.getSession().setAttribute("msg","执行了add方法");
            }
            if (method.equals("delete")){
                req.getSession().setAttribute("msg","执行了delete方法");
            }
        //2.调用业务层

        //3.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 {
        doGet(req, resp);
    }
}

5.编写`test.jsp`，在WEB-INF目录下新建jsp文件夹，新建test.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

${msg}

</body>
</html>

6.`web.xml`中注册servlet

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

<!--    <session-config>-->
<!--        <session-timeout>15</session-timeout>-->
<!--    </session-config>-->

<!--    <welcome-file-list>-->
<!--        <welcome-file>index.jsp</welcome-file>-->
<!--    </welcome-file-list>-->

</web-app>