一、Spring MVC基础

一、Spring MVC概述

1.1 说明

MVC与三层架构：
MVC（Model View Controller）:模型视图控制器。
三层架构：展现层、应用层、数据访问层。

Spring MVC提供了一个DispatcherServlet来开发一个web应用。在Servlet2.5以下的版本只要在web.xml中配置servlet元素即可。博主将会使用Servlet3.0+无web.xml的配置方式，在Spring MVC里实现WebApplicationInitializer接口实现等同于web.xml的配置。因为SpringBoot推荐使用注解配置或者Java配置研发，我们渐渐的习惯于基于这种配置开发。

1.2 实例

1）pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dy</groupId>
    <artifactId>springmvc-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <jsp.version>2.2</jsp.version>
        <jstl.version>1.2</jstl.version>
        <servlet.version>3.1.0</servlet.version>
        <spring-framework.version>5.0.1.RELEASE</spring-framework.version>
        <logback.version>1.2.3</logback.version>
        <slf4j.version>1.7.5</slf4j.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-web-api</artifactId>
            <version>7.0</version>
            <scope>provided</scope>
        </dependency>

        <!--Spring MVC-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring-framework.version}</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl.version}</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>${servlet.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>${jsp.version}</version>
        </dependency>

        <!--Spring and Transaction-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${spring-framework.version}</version>
        </dependency>

        <!--使用JLF4J和LogBack作为日志-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>${logback.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${logback.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-access</artifactId>
            <version>${logback.version}</version>
        </dependency>

    </dependencies>

    <!--maven编译插件/Java的编译级别-->
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.3</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

2）logback.xml

<?xml version="1.0" encoding="UTF-8" ?>
<configuration scan="true" scanPeriod="1 seconds">
    <contextListener class="ch.qos.logback.classic.jul.LevelChangePropagator">
        <resetJUL>true</resetJUL>
    </contextListener>

    <jmxConfigurator/>

    <appender name="console" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>
                logbak: %d{HH:mm:ss.SSS} %logger{36} -%msg%n
            </pattern>
        </encoder>
    </appender>
    <logger name="org.springframework.web" level="DEBUG"></logger>

    <root level="info">
        <appender-ref ref="console"/>
    </root>
</configuration>

3）演示页面
在src/main/resources下建立views目录，并在此目录下新建index.jsp。

<%@page language="java" contentType="text/html; UTF-8" pageEncoding="UTF-8" %>
<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>首页</title>
</head>
<body>
    <pre>
        Welcome to Spring MVC world!
    </pre>
</body>
</html>

说明：页面放在src/main/resources是为了方便以后的SpringBoot习惯。

4）Spring MVC的配置

package com.dy.springmvc.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

/**
 * Author:dy_bom
 * Description:
 * Date:Created in 下午11:58 2018/4/2
 * Copyright (c)  [email protected] All Rights Reserved.
 */
@Configuration
@EnableWebMvc
@ComponentScan("com.dy.springmvc")
public class MyMvcConfig {

    @Bean
    public InternalResourceViewResolver viewResolver(){
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/classes/views/");
        viewResolver.setSuffix(".jsp");
        viewResolver.setViewClass(JstlView.class);
        return viewResolver;
    }
}

5）web配置

package com.dy.springmvc.config;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

/**
 * Author:dy_bom
 * Description:WebApplicationInitializer是Spring提供用来配置Servlet3.0+配置的接口
 * Date:Created in 上午12:02 2018/4/3
 * Copyright (c)  [email protected] All Rights Reserved.
 */
public class WebInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.register(MyMvcConfig.class);
        context.setServletContext(servletContext); //注册配置类


        //注册SpringMVC的DispatcherServlet
        ServletRegistration.Dynamic servlet = servletContext.addServlet("dispatcher",new DispatcherServlet(context));
        servlet.addMapping("/");
        servlet.setLoadOnStartup(1);
    }
}

6）简单的控制器

package com.dy.springmvc.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

/**
 * Author:dy_bom
 * Description:
 * Date:Created in 上午12:08 2018/4/3
 * Copyright (c)  [email protected] All Rights Reserved.
 */
@Controller  
public class HelloController {

    @GetMapping({"/index","/"})
    public String hello(){
        return "index";
    }
}

7）启动
启动页面

代码：点我
下一篇：Spring MVC进阶

一、Spring MVC概述

1.1 说明

1.2 实例

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