spring in action 3学习（一）装配bean

从事java开发工作已有1年多，期间学了很多，各项技术学的很快，但，忘得更快。如今工作、生活各项都相对稳定，想好好巩固下基础，在此申请了博客园，打算留下学习的足迹。留背将来复习或回味。

（一）声明一个简单bean

public class Juggler implements Performer{

    private int beanBags = 3;
    
    public Juggler() {
    }
    
    public Juggler(int beanBags) {
        this.beanBags = beanBags;
    }
    
    @Override
    public void perform() {
        
        System.out.println("JUGGLER " + beanBags + " BEANSBAGS");
    }

}

（二）创建spring配置

beans.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: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-3.0.xsd
  http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
    >

    <bean id = "duke" class = "org.springbaisc.Juggler" />

</beans>

spring-idol.xml

通过构造器注入

<?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: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-3.0.xsd
  http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
    >

    <bean id = "duke1" class = "org.springbaisc.Juggler" >
        <constructor-arg value="15"></constructor-arg><!-- 通过构造器注入 -->
    </bean>

</beans>

测试代码

public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("config/beans.xml","config/spring-idol.xml");//多配置文件
        Performer performer = (Performer) ctx.getBean("duke");
        Performer performer1 = (Performer) ctx.getBean("duke1");
        performer.perform();
        performer1.perform();
    }

输入结果

JUGGLER 3 BEANSBAGS
JUGGLER 15 BEANSBAGS

通过构造器注入对象引用

public interface Poem {

    void recite();
}

public class Sonnet29 implements Poem{

    private static String[] LINES = {
            "When,in disgrace with fortune and men's eyes",
            "I all alone beweep my outcast state"
    };
    
    public Sonnet29(){
        
    }
    
    @Override
    public void recite() {

        for(String str : LINES){
            System.out.println(str);
        }
    }

}

public class PoeticJuggler extends Juggler{

    private Poem poem;
    
    public PoeticJuggler(Poem poem){
        super();
        this.poem = poem;
    }
    
    public PoeticJuggler(int beanBags,Poem poem){
        super(beanBags);
        this.poem = poem;
    }
    
    public void perform(){
        super.perform();
        System.out.println("While reciting...");
        poem.recite();
    }
}

配置文件

<bean id="sonnet29" class="org.springbaisc.Sonnet29"></bean>

    <bean id="poeticDuke" class="org.springbaisc.PoeticJuggler">
        <constructor-arg value="15" />
        <constructor-arg ref="sonnet29" />
    </bean>

输出结果

JUGGLER 15 BEANSBAGS
While reciting...
When,in disgrace with fortune and men's eyes
I all alone beweep my outcast state