Spring Bean简单应用实例

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Spring Bean简单应用实例装配bean bean注入

学习的Spring实战(第三版)Bean的简单应用

1.创建一个表演者的接口

package com.performer.service;

public interface Performer {
	void perform();
}

2.创建一个杂技师表演者Bean，杂技师空中抛球(beanBags)，抛的越多越厉害，默认有3个

package com.performer.service.impl;

import com.performer.service.Performer;

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+" beanBags");
	}
}

3.配置文件Spring1.xml中加载Bean，实例化杂技师(Duke)

<?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-3.0.xsd">

<bean id="duke" class="com.performer.service.impl.Juggler">
</bean>
</beans>

4.加载配置文件Spring1.xml，测试Duke，输出他拥有的beanBags

package com.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.performer.service.impl.Juggler;

public class SpringTest {
	public static void main(String []args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("spring1.xml");
		Juggler juggle = (Juggler) context.getBean("duke");
		juggle.perform();
	}
}

5.测试结果，如下所示

6.通过构造器，让Duke拥有15个beanBags，配置文件如下

<bean id="duke" class="com.performer.service.impl.Juggler">
	<constructor-arg value="15"></constructor-arg>
</bean>
</beans>

7.加载配置文件Spring2.xml，测试Duke，输出他拥有的beanBags

public class SpringTest {
	public static void main(String []args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("spring2.xml");
		Juggler juggle = (Juggler) context.getBean("duke");
		juggle.perform();
	}
}

8.测试结果如下所示

现在创建一个会唱诗歌的杂技师

9.创建诗歌借口

package com.poem.service;

public interface Poem {
	void recite();
}

10.创建一首诗

package com.poem.service.impl;

import com.poem.service.Poem;

public class Sonnet implements Poem {
	Sonnet() {
	}
	
	private String[] s={"百日依山尽","黄河入海流","欲穷千里目","更上一层楼"};
	
	@Override
	public void recite() {
		for(int i=0;i<s.length;i++) {
			System.out.println(s[i]);
		}
	}
}

11.创建会朗诵诗歌的杂技师PoeticJuggler

package com.performer.service.impl;

import com.poem.service.Poem;

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();
	}
}

12.将诗歌给Duke，让Duke成为PoeticJuggler，配置文件如下

<bean id="duke" class="com.performer.service.impl.PoeticJuggler">
	<constructor-arg value="15"></constructor-arg>
	<constructor-arg ref="sonnet"></constructor-arg>
</bean>

<bean id="sonnet" class="com.poem.service.impl.Sonnet"></bean>

13.加载Spring3.xml，进行测试，查看结果Duke成为会诗歌的杂技师

public class SpringTest {
	public static void main(String []args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("spring3.xml");
		Juggler juggle = (Juggler) context.getBean("duke");
		juggle.perform();
	}
}

14.运行结果如下所示

其它装配Bean的写法，如下

15.注入简单值，见Spring4.xml

<bean id="jake" class="com.performer.service.impl.Instrumentalist">
	<property name="song" value="small star"></property>
</bean>

16.引用其他Bean，见Spring5.xml

<bean id="jake" class="com.performer.service.impl.Instrumentalist">
	<property name="song" value="small star"></property>
	<property name="instrument" ref="piano"></property>
</bean>
<bean id="piano" class="com.instrument.service.impl.Piano"></bean>

17.注入内部Bean，见Spring6.xml和Spring7.xml

<bean id="jake" class="com.performer.service.impl.Instrumentalist">
	<property name="song" value="small star"></property>
	<property name="instrument">
		<bean class="com.instrument.service.impl.Saxophone"></bean>    
	</property>
</bean>
<bean id="saxophone" class="com.instrument.service.impl.Saxophone"></bean>

<bean id="duke" class="com.performer.service.impl.PoeticJuggler">
	<constructor-arg value="15"></constructor-arg>
	<constructor-arg >
		<bean class="com.poem.service.impl.Sonnet"></bean>
	</constructor-arg>
</bean>

18.使用Spring命名空间p装配属性Spring8.xml

19.装配集合

<bean id="hank" class="com.performer.service.impl.OneManBand">
	<property name="instruments" >
		<!-- 使用set -->
		<!-- <set>
			<ref bean="guitar"/>
			<ref bean="piano"/>
			<ref bean="saxophone"/>
		</set> -->
		
		<!-- 使用list -->
		<!-- <list>
			<ref bean="guitar"/>
			<ref bean="piano"/>
			<ref bean="saxophone"/>
		</list> -->
		
		<!-- 使用map -->
		<map>
			<entry key="GUITAR" value-ref="guitar"></entry>
			<entry key="PIANO" value-ref="piano"></entry>
			<entry key="SAXOPHONE" value-ref="saxophone"></entry>
		</map>  
		
		<!-- 使用props -->
	        <!-- <props>
			<prop key="GUITAR">wing wing wing...</prop>
			<prop key="PIANO">ding ding ding...</prop>
			<prop key="SAXOPHONE">plink plink plink...</prop>
		</props> -->
	</property>
</bean>

<bean id="guitar" class="com.instrument.service.impl.Guitar"></bean>

<bean id="saxophone" class="com.instrument.service.impl.Saxophone"></bean>

<bean id="piano" class="com.instrument.service.impl.Piano"></bean>

20.测试装配集合

public class OneManBand implements Performer {
	public OneManBand() {
	}
	
	/*使用list*/
	
	private List<Instrument> instruments; 
	
	@Override
	public void perform() {
		for(Instrument instrument : instruments) {
			instrument.play();
		}
	}

	public List<Instrument> getInstruments() {
		return instruments;
	}

	public void setInstruments(List<Instrument> instruments) {
		this.instruments = instruments;
	}
	
	/*使用Map*/
	
    /*private Map<String,Instrument> instruments; 
	
	@Override
	public void perform() {
		for(String key : instruments.keySet()) {
			System.out.print(key+":");
			Instrument instrument = instruments.get(key);
			instrument.play();
		}
	}
	
	public Map<String,Instrument> getInstruments() {
		return instruments;
	}

	public void setInstruments(Map<String,Instrument> instruments) {
		this.instruments = instruments;
	}*/

	/*使用Collection*/
	
	/*private Collection<Instrument> instruments;  
	
	@Override
	public void perform() {
		for(Instrument instrument : instruments) {
			instrument.play();
		}
	}
	
	public Collection<Instrument> getInstruments() {
		return instruments;
	}
	
	public void setInstruments(Collection<Instrument> instruments) {
		this.instruments = instruments;
	}*/
}

21.运行结果如下所示