Spring MVC hello world annotatio
2015-08-19 本文已影响113人
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Technologies used :
- Spring 2.5.6
- JDK 1.6
- Maven 3
- Eclipse 3.6
1. Directory Structure
spring2-mvc-annotation-hello-world.png
2. Maven
Spring’s annotation is bundled in the same ·spring-webmvc.jar·.
pom.xml
<?xml version="1.0"?>
<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.mkyong.common</groupId>
<artifactId>spring2-mvc-annotation-hello-world</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>Spring 2 MVC</name>
<properties>
<jdk.version>1.6</jdk.version>
<spring.version>2.5.6</spring.version>
<jstl.version>1.2</jstl.version>
<servletapi.version>2.5</servletapi.version>
</properties>
<dependencies>
<!-- Spring MVC framework -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- JSTL -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>${jstl.version}</version>
</dependency>
<!-- for compile only, your container should have this -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>${servletapi.version}</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>${jdk.version}</source>
<target>${jdk.version}</target>
</configuration>
</plugin>
<plugin>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>9.2.11.v20150529</version>
<configuration>
<scanIntervalSeconds>10</scanIntervalSeconds>
<webApp>
<contextPath>/spring2</contextPath>
</webApp>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.9</version>
<configuration>
<downloadSources>true</downloadSources>
<downloadJavadocs>true</downloadJavadocs>
<wtpversion>2.0</wtpversion>
<wtpContextName>spring2</wtpContextName>
</configuration>
</plugin>
</plugins>
</build>
</project>
3. Controller & Handler Mapping
Now, you can use @Controller and @RequestMapping to replace the XML configuration.
-
Controller– The controller class is no longer need to extend the base controller likeAbstractControllerorSimpleFormController, just simply annotate the class with a@Controllerannotation. -
Handler Mapping – No more declaration for the handler mapping like
BeanNameUrlHandlerMapping,ControllerClassNameHandlerMappingorSimpleUrlHandlerMapping, all are replaced with a standard@RequestMappingannotation.
HelloWorldController.java
package com.mkyong.common.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
@Controller
@RequestMapping("/welcome")
public class HelloWorldController{
@RequestMapping(method = RequestMethod.GET)
public ModelAndView helloWorld(){
ModelAndView model = new ModelAndView("HelloWorldPage");
model.addObject("msg", "hello world");
return model;
}
}
If the @RequestMapping is applied at the class level (can apply at method level with multi-actions controller), it required to put a RequestMethod to indicate which method to handle the mapping request.
In this case, if a URI pattern /welcome is requested, it will map to this HelloWorldController
, and handle the request with helloWorld() method.
4. Spring XML Configuration
You still need to configure the view resolver and component scanning in XML file.
/WEB-INF/spring-mvc-config.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd">
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
<context:component-scan base-package="com.mkyong.common.controller" />
</beans>
5. JSP Page
A simple JSP page for demonstration.
HelloWorldPage.jsp.
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<body>
<h1>Spring MVC Hello World Annotation Example</h1>
<h2>${msg}</h2>
</body>
</html>
6. web.xml
web.xml
<?xml version="1.0"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>Spring Web MVC Application</display-name>
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring-mvc-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>*.htm</url-pattern>
</servlet-mapping>
</web-app>
7. Demo
7.1 To run with the embedded Jetty, type :
$ mvn jetty:run
URL : http://localhost:8080/spring2/welcome.htm
spring2-mvc-annotation-demo.png
7.2 To import into Eclipse IDE.
$ mvn eclipse:eclipse
Note
If you compare this Spring MVC annotation-based hello world example with XML, you can see that this annotation approach is easier and flexible in wiring the controller class and URL handler mapping, because you do not need to declare the controller class explicitly or extends any particular class.
