一、SpringMVC入门案例

一、环境搭建

创建Maven工程，选择webapp

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.liaoxiang</groupId>
    <artifactId>springMVC_1-1_start</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>springMVC_1-1_start Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <!--版本锁定-->
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <spring.version>5.0.2.RELEASE</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.0</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>

    <build>
        <finalName>springMVC_1-1_start</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.0.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.7.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.20.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>

</project>

web.xml

<!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
    <display-name>Archetype Created Web Application</display-name>

    <!--配置前端控制器-->
    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <!--所有请求都会经过该dispatcherServlet-->
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

配置到本地tomcat

点+号


点击ok

二、入门案例

页面请求index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h3>入门程序</h3>
    <a href="/hello">入门程序</a>
    <br>
    <a href="/testRequestMapping?username=jack">RequestMapping注解</a>
</body>
</html>

编写Controller类处理请求

@Controller
public class HelloController {
    /**
     * 入门案例
     * @return
     */
    @RequestMapping(path="/hello")
    public String sayHello(){
        System.out.println("Hello StringMVC");
        // 方法执行完跳转到success.jsp页面
        return "success";
    }
}

在springmvc配置文件中开启spring注解支持，将该类加载到容器中，并开启SpringMVC框架注解的支持，Controller方法还行完成后跳转到另一个页面，需要配置试图解析器InternalResourceViewResolver

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

    <!-- 开启注解扫描 -->
    <context:component-scan base-package="com.liaoxiang"/>

    <!-- 视图解析器对象，返回页面的跳转，找到该视图解析器 -->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--文件所在目录-->
        <property name="prefix" value="/WEB-INF/pages/"/>
        <!--文件的后缀名-->
        <property name="suffix" value=".jsp"/>
    </bean>
    
    <!-- 开启SpringMVC框架注解的支持 @RequestMapping...-->
    <mvc:annotation-driven conversion-service="conversionService"/>
</beans>

同时需要在web.xml中配置加载springmvc.xml配置文件的时机

<!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
    <display-name>Archetype Created Web Application</display-name>

    <!--配置前端控制器-->
    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--初始化参数，加载springmvc配置文件-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <!--启动服务器创建DispatcherServlet对象，加载配置文件-->
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <!--所有请求都会经过该dispatcherServlet-->
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

在WEB-INF文件下新建成功跳转的页面

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h3>入门成功</h3>
</body>
</html>

启动服务器，进入页面点击跳转，控制台打印



入门案例过程：
启动服务器：配置了<load-on-startup>1</load-on-startup>，所以DispatcherServlet被加载，同时springmvc配置文件被加载，创建Controller对象和视图解析器对象internalResourceViewResolver，并加入到IOC容器，配置了SpringMVC框架的注解，sayHello()方法能够处理请求
当浏览器上点击链接，发送/hello请求，首先到达DispatcherServlet，然后根据路径执行sayHello()方法，方法执行返回"success"给DispatcherServlet，又经过internalResourceViewResolver的解析将success页面经过DispatcherServlet返回给浏览器。