四-Spring MVC基础-MVC、项目搭建-【JavaEE开发的颠覆者】

一、Spring MVC

1.MVC是什么？三层架构是什么？
MVC：Model+View+Controller(数据模型+视图+控制器)
三层架构：Presentation tier+Application tier+Data tier(展现层+应用层+数据访问层)
2.MVC和三层架构的关系
实际上MVC只存在三层架构的展现层，M实际上是数据模型，是包含数据的对象。在SpringMVC里，有一个专门的类叫Model，用来和V之间的数据交互、传值；V指的是视图页面，包含JSP、freeMarker、Thymeleaf等；C当然就是控制器(SpringMVC的注解@Controller的类)。
而三层架构是整个应用的架构，是由Spring框架负责管理的。一般项目结构中都有Service层、Dao层，这两个反馈在应用层和数据访问层。

二、项目搭建

1.构建maven项目
（1）pom文件

<?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</groupId>
    <artifactId>zhao</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <java.version>1.7</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

        <!--Web-->
        <jsp.version>2.2</jsp.version>
        <jstl.version>1.2</jstl.version>
        <servlet.version>3.1.0</servlet.version>

        <!--Spring-->
        <spring-framework.version>4.1.5.RELEASE</spring-framework.version>
        <!--Logging-->
        <logback.version>1.0.13</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>

        <!--其他web依赖-->
        <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>
            <scope>provided</scope>
        </dependency>

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

        <!--使用SLF4J和LogBack作为日志-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.16</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>${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>

    <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）在src/main/resources目录下，新建logback.xml用来配置日志。

<?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>

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

    <logger name="org.springframework.web" level="DEBUG"/>
    <root level="info">
        <appender-ref ref="console"/>
    </root>

</configuration>

2.在src/main/resources下建立views目录，新建index.jsp

<%@ page language="java" contentType="text/html charset=UTF-8"
         pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "~//W3C//DTD HTML4.01 Transitional"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <title>标题</title>
    </head>
    <body>
        <pre>
            Welcome to Spring MVC world
        </pre>
    </body>
</html>

3.配置类

@Configuration
@EnableWebMvc
@ComponentScan("com.zhao.springMVC.SpringMVCfirst")
public class FirstMVCConfig {
    @Bean
    public InternalResourceViewResolver viewResolver(){
        InternalResourceViewResolver viewResolver=new
                InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/class/views/");
        viewResolver.setSuffix(".jsp");
        viewResolver.setViewClass(JstlView.class);
        return viewResolver;
    }

}
/**
 * 这只是一个普通的配置类。
 * 这里我们配置了一个JSP的ViewResolver,用来映射路径和实际页面的位置。
 * @EnableWebMvc注解会开启一些默认配置，如一些ViewResolver或者MessageConverter等
 */