Spring MVC的Hello World例子

以下内容引用自http://wiki.jikexueyuan.com/project/spring/mvc-framework/spring-mvc-hello-world-example.html：

例子：

目录结构：

pom.xml：

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.jsoft.testspring</groupId>
    <artifactId>testmvchelloworld</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>testmvchelloworld Maven Webapp</name>
    <url>http://maven.apache.org</url>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <!-- Servlet Library -->
        <!-- http://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

        <!-- Spring Core -->
        <!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>

        <!-- Spring Web -->
        <!-- http://mvnrepository.com/artifact/org.springframework/spring-web -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>

        <!-- Spring Web MVC -->
        <!-- http://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>

    </dependencies>
    <build>
        <finalName>testmvchelloworld</finalName>
        <plugins>
            <!-- Config: Maven Tomcat Plugin -->
            <!-- http://mvnrepository.com/artifact/org.apache.tomcat.maven/tomcat7-maven-plugin -->
            <!-- http://tomcat.apache.org/maven-plugin-2.0/tomcat7-maven-plugin/plugin-info.html -->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <!-- Config: contextPath and Port (Default:8080) -->
                <!--
                <configuration>
                    <path>/</path>
                    <port>8899</port>
                </configuration>
                 -->
            </plugin>
            <!-- Config: Maven Jetty Plugin -->
            <!-- http://mvnrepository.com/artifact/org.mortbay.jetty/jetty-maven-plugin -->
            <!-- http://www.eclipse.org/jetty/documentation/current/jetty-maven-plugin.html -->
            <plugin>
                <groupId>org.eclipse.jetty</groupId>
                <artifactId>jetty-maven-plugin</artifactId>
                <version>9.4.3.v20170317</version>
                <!-- Config: contextPath and Port (Default:8080) -->
                <!--
                <configuration>
                    <httpConnector>
                        <port>8899</port>
                    </httpConnector>
                    <webAppConfig>
                        <contextPath>/</contextPath>
                    </webAppConfig>
                </configuration>
                 -->
            </plugin>
        </plugins>
    </build>
</project>

POM上配置了Tomcat7的插件和Jetty的插件，在Eclipse运行时不用Run on Server，而是直接命令行启动：mvn tomcat7:run/mvn jetty:run。

web.xml:

<web-app id="WebApp_ID" version="3.0"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                                 http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

   <display-name>Spring MVC Application</display-name>

   <servlet>
       <servlet-name>spring-mvc</servlet-name>
       <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
       <!-- 默认：[servlet-name]-servlet.xml -->
       <!-- 通过初始化参数，指定xml文件的位置 -->
       <init-param>
           <param-name>contextConfigLocation</param-name>
           <param-value>/WEB-INF/helloworld-context.xml</param-value>
       </init-param>
       <load-on-startup>1</load-on-startup>
   </servlet>   

   <servlet-mapping>
       <servlet-name>spring-mvc</servlet-name>
       <url-pattern>/</url-pattern>
   </servlet-mapping>

   <!-- 添加其它xml配置 -->
   <context-param>
       <param-name>contextConfigLocation</param-name>
       <param-value>/WEB-INF/other-context.xml</param-value>
   </context-param>
   <listener>
       <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
   </listener>

</web-app>

helloworld-context.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"
       xmlns:p="http://www.springframework.org/schema/p"
       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">

   <context:component-scan base-package="com.jsoft.testspring.testmvchelloworld"/>

   <context:annotation-config/>

   <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/jsp/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
   </bean>

</beans>

这里就是一个Bean，确定视图的位置以及后缀。

HelloController.java：

package com.jsoft.testspring.testmvchelloworld;

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

@Controller
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping(method=RequestMethod.GET)
    public String printHello(ModelMap model){
        model.addAttribute("message","Hello Spring MVC Framework!");
        return "hello";
    }
}

hello.jsp：

<%@ page contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Hello World</title>
</head>
<body>
    <h2>${message}</h2>
</body>
</html>

运行：

mvn tomcat7:run

运行结果：

测试工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test19/testmvchelloworld