Spring初体验

java开发4年经验，现在才在项目中真正用上Spring，惭愧。

1 生成目录结构

IDEA生成工程目录机构和pom.xml：

File-> New -> Project…->Maven -> 勾选Create from archetype -> org.apache.camel.archetypes:maven-archetype-quickstart -> Next ->

生成的目录结构(除了resources目录和java文件)如下：

springlearn
    |─pom.xml
    |─src
        |─main
        |   |─java
        |       |-indi.zhb
        |               |-Quest.java
        |               |-SlayDragonQuest.java
        |               |-Knight.java
        |               |-BraveKnight.java
        |               |-App.java
        |
        |   |─resources
        |       |─spring.xml
        |
        |─test
            |─java

2. pom.xml

生成的pom.xml如下：

<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>indi.zhb</groupId>
  <artifactId>springlearn</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>springlearn</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>

  </dependencies>
</project>

参考官方文档https://projects.spring.io/spring-framework/ ，加入spring依赖：

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>4.3.9.RELEASE</version>
</dependency>

代码内容（改自Spring in action第一章）

Quest.java

package indi.zhb;

/**
 * Created by huabinzheng on 2017/6/26.
 */
public interface Quest {
    void embark();
}

SlayDragonQuest.java

package indi.zhb;

import java.io.PrintStream;

/**
 * Created by huabinzheng on 2017/6/26.
 */
public class SlayDragonQuest implements Quest {
    private PrintStream stream;
    public SlayDragonQuest(PrintStream stream) {
        this.stream = stream;
    }

    public void embark() {
        stream.println("Embarking on quest to slay the dragon!");
    }
}

Knight.java

package indi.zhb;

/**
 * Created by huabinzheng on 2017/6/26.
 */
public interface Knight {
    public void embarkOnQuest();
}

BraveKnight.java

package indi.zhb;

/**
 * Created by huabinzheng on 2017/6/26.
 */
public class BraveKnight implements Knight {
    private Quest quest;

    public BraveKnight(Quest quest) {
        this.quest = quest;
    }

    public void embarkOnQuest() {
        quest.embark();
    }
}

App.java

package indi.zhb;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App 
{
    public static void main( String[] args )
    {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
        BraveKnight knight = context.getBean(BraveKnight.class);
        knight.embarkOnQuest();
        context.close();
    }
}

Spring配置文件

用IDE来生成配置文件框架：右击resources-> New -> XML Configuration File -> Spring Config，取名为spring.xml，内容如下，

<?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">

</beans>

往xml文件添加bean：

<bean id = "knight" class = "indi.zhb.BraveKnight">
    <constructor-arg ref = "quest" />
</bean>

<bean id="quest" class="indi.zhb.SlayDragonQuest">
    <constructor-arg value="#{T(System).out}"/>
</bean>