芯が強い人になるESTJ-A

父工程的依赖包导入

1.1

    <!--父工程的依赖包-->
    <dependencies>
        <!--单元测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <!--springMVC-->
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <!--servlet-->
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <!--jsp-->
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <!--jstl-->
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    </dependencies>

1.2编写一个Servlet类，用来处理用户请求

1.3什么是springMVC
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springMVC=Java程序代码为主的，Servlet
官方文档：-->link
link2

我们为什么要去学习springMVC？？

1轻量级，简单易学
2高效，基于请求响应的MVC框架
3与spring兼容性好
4约定》配置
5功能强大，RESTful，数据验证，格式化，本地化，主题
6简单灵活

Spring的web框架，围绕DispacherServlet设计。

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原理，听一遍，写10遍，没有笨人，只有懒人。

hellospringMVC

配置版

1新建一个model
2确定导入了，springMVC的依赖
3配置web.xml，注册DispatchServlet

web.xml

<?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">

    <!--1DispatcherServlet,配置servlet的name和mapping-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--2绑定文件-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!--3自动启动1-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <!--配置乱码过滤器-->
    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/</url-pattern>
    </filter-mapping>
</web-app>

springmvc-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">
    <!--固定,映射器+处理器+视图层-->
    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
    <!--视图层可变,模版引擎，Thymeleaf，Freemarker-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/" />
        <!--后缀-->
        <property name="suffix" value=".jsp" />
    </bean>

    <!--Handler-->
    <bean id="/hello" class="com.xuwen.controller.HelloController"/>

</beans>

HelloController类

package com.xuwen.controller;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * author:xuwen
 * Created on 2021/7/29
 */
public class HelloController implements Controller {
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        ModelAndView mv = new ModelAndView();
        //业务代码
        String result = "HelloSpringMVC";
        mv.addObject("msg",result);
        //视图跳转
        mv.setViewName("test");//jsp文件夹包下的test文件
        return mv;
    }
}

注解开发版！！！

第1步：配置web.xml

注意：1。1webxml需要最新版
1.2注册DispatcherServlet
1.3关联springMVC的配置文件
1.4启动级别1
1.5映射路径是/，如果是/*会404

参考

<?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>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

第2步：resources文件下--新建：springmvc-servlet.xml一摸一样

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--自动扫描包，让指定注解生效,IOC统一管理-->
    <context:component-scan base-package="com.xuwen.controller"/>
    <!--固定springmvc,不处理静态资源-->
    <mvc:default-servlet-handler/>
    <!--固定-->
    <mvc:annotation-driven />

    <!--JSON乱码解决问题-->
    <!--JSON乱码问题配置，这段完完全全写死的-->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>


    <!--视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/" />
        <!--后缀-->
        <property name="suffix" value=".jsp" />
    </bean>

</beans>

第3步：写controller，新建一个类，用注解开发

package com.xuwen.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * author:xuwen
 * Created on 2021/7/29
 */
@Controller
public class HelloController {
    //普通方法
    @RequestMapping("/hello")
    public String hello(Model model){
        //封装数据
        model.addAttribute("msg","Hello,SpringMVC-Annotation");
        //return到哪个视图？
        return "hello";
    }

}

第4步：配置tomcat，启动tomcat

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springmvc总结

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SpringMVC：controller和RestFul风格

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SpringMVC：结果跳转方式

SpringMVC：数据处理

JSON

json->javascript对象：
JSON.parse();
var obj = JSON.parse('{"a":"hello","b":"world"}');

javascript->JSON;
JSON.stringfy();
var json = JSON.stringfy({a:'hello',b:'world'});
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# SpringMVC=底层就是servlet