[Spring实战系列]（2）Maven创建Spring-HelloWorld项目-白红宇

了解Spring的朋友都知道，创建一个Spring Framework项目都需要依赖什么样的Jar包。如果不使用Maven，那么在项目中就需要手动下载相关的依赖。由于Spring Framework又会依赖与其他开源类库，因此实际中往往会下载Spring Framework的jar包，还的下载所有它依赖的其他jar包。这么做往往就引入了很多不必要的依赖。另一种做法是只下载Spring Framework的jar包，不包含其他的相关依赖，到实际使用的时候，再根据报错信息，或者查询相关文档，加入需要的其他依赖。

1. 创建Maven项目

如果对Maven不太了解的可以参考：

使用IDE创建一个Maven项目非常简单，选择菜单项File->New->Other，在弹出的对话框中选择Maven下的Maven Project,然后点击Next按钮：

在弹出的New Maven Project对话框中，使用默认的选项，然后点击Next按钮：

此时m2eclipse会提示我们选择一个Archetype。这里选择maven-archetype-quickstart,再点击Next按钮：

此时输入groupId，artifactId，version，package：

点击Finish即可完成。

2. 添加依赖配置

pom.xml

2.1 Spring2.xxx

<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.sjf.springdemo</groupId>
 <artifactId>springdemo-helloworld</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <packaging>jar</packaging>
 
 <name>springdemo-helloworld</name>
 <url>http://maven.apache.org</url>
 
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 </properties>
 
 <dependencies>
 <dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>3.8.1</version>
 <scope>test</scope>
 </dependency>
 
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring</artifactId>
 <version>2.5.6</version>
 </dependency>
 
 </dependencies>
</project>

2.2 Spring3.xxx

<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.sjf.springdemo</groupId>
 <artifactId>springdemo-helloworld</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <packaging>jar</packaging>
 
 <name>springdemo-helloworld</name>
 <url>http://maven.apache.org</url>
 
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 </properties>
 
 <dependencies>
 <dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>3.8.1</version>
 <scope>test</scope>
 </dependency>
 
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-context</artifactId>
 <version>4.2.4.RELEASE</version>
 </dependency>
 
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-core</artifactId>
 <version>4.2.4.RELEASE</version>
 </dependency>
 
 </dependencies>
</project>

3. 编译查看Maven是否创建成功

运行mvn clean compile命令：

Run：

[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] Building springdemo-helloworld 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ springdemo-helloworld ---
[INFO] Deleting D:\WorkSpace\EclipseCode\springdemo-helloworld\target
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ springdemo-helloworld ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory D:\WorkSpace\EclipseCode\springdemo-helloworld\src\main\resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ springdemo-helloworld ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to D:\WorkSpace\EclipseCode\springdemo-helloworld\target\classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 7.292 s
[INFO] Finished at: 2016-01-30T15:24:11+08:00
[INFO] Final Memory: 9M/23M
[INFO] ------------------------------------------------------------------------

BUILD SUCCESS则表示创建Maven成功。

4. Spring bean主代码

在src/main/java/com/sjf/bean/下

创建HellloWorld类，

Spring的bean仅仅是一个普通的Java类，稍后在Spring bean配置文件中声明。

package com.sjf.bean;
 
/**
 * hello world 类
 * @author sjf0115
 *
 */
public class HelloWorld { 
 private String name;
 
 public void setName(String name) { 
 this.name = name;
 }
 
 public void sayHello(){ 
 System.out.println("welcome "+ name +" to spring world...");
 }
}

5. Spring bean配置文件

在src/main/resources创建applicationContext.xml文件，

这是的Spring bean的配置文件，该文件告知所有可用的Spring bean。

applicationContext.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"
 xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
 
 <!-- 配置bean -->
 <bean id = "helloworld" class = "com.sjf.bean.HelloWorld">
 <property name="name" value="sjf0115"></property>
 </bean>
 
</beans>

6.项目结构

Spring2.xxx：

Spring3.xxx：

7.运行

src/main/java下创建Test.java：

package com.sjf.bean;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
 
/**
 * 测试类
 * @author sjf0115
 *
 */
public class Test { 
 
 private static ApplicationContext context;
 private static HelloWorld helloWorld;
 
 public static void main(String[] args) { 
 context = new ClassPathXmlApplicationContext("applicationContext.xml");
 // 2. 从IOC容器中获取Bean实例
 helloWorld = (HelloWorld)context.getBean("helloworld");
 // 3.调用sayHello方法
 helloWorld.sayHello();
 }
}

运行结果：

一月 30, 2016 3:53:19 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@164b9b6: display name [org.springframework.context.support.ClassPathXmlApplicationContext@164b9b6]; startup date [Sat Jan 30 15:53:19 CST 2016]; root of context hierarchy

一月 30, 2016 3:53:19 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

INFO: Loading XML bean definitions from class path resource [applicationContext.xml]

一月 30, 2016 3:53:19 下午 org.springframework.context.support.AbstractApplicationContext obtainFreshBeanFactory

INFO: Bean factory for application context [org.springframework.context.support.ClassPathXmlApplicationContext@164b9b6]: org.springframework.beans.factory.support.DefaultListableBeanFactory@18b6281

一月 30, 2016 3:53:19 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons

INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@18b6281: defining beans [helloworld]; root of factory hierarchy

welcome sjf0115 to spring world...