一Spring MVC基础
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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，来实现等同于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 示例
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>
<?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) xdy_0722@sina.com 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) xdy_0722@sina.com 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) xdy_0722@sina.com All Rights Reserved. */
@Controller public class HelloController {
@GetMapping({"/index","/"}) public String hello(){ return "index"; } }
7）启动