Spring中為了減少xml中配置，可以宣告一個配置類（例如SpringConfig）來對bean進行配置。

一、首先，需要xml中進行少量的配置來啟動Java配置:

<?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:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="
			http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
			http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
			http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
			http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">
   <context:component-scan base-package="SpringStudy.Model">
    </context:component-scan>
</beans>
 

用@Configuration註解該類，等價 與XML中配置beans；用@Bean標註方法等價於XML中配置bean。

程式碼如下：

package SpringStudy;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import SpringStudy.Model.Counter;
import SpringStudy.Model.Piano;

@Configuration
public class SpringConfig {

	@Bean
	public Piano piano(){
		return new Piano();
	}
	@Bean(name = "counter") 
	public Counter counter(){
		return  new Counter(12,"Shake it Off",piano());
	}
}
 

Counter：

package SpringStudy.Model;

public class Counter {
	public  Counter() {
	}

	public  Counter(double multiplier, String song,Instrument instrument) {
		this.multiplier = multiplier;
		this.song = song;
		this.instrument=instrument;
	}

	private double multiplier;

	private String song;

	@Resource
	private Instrument instrument;

	public double getMultiplier() {
		return multiplier;
	}

	public void setMultiplier(double multiplier) {
		this.multiplier = multiplier;
	}


	public String getSong() {
		return song;
	}

	public void setSong(String song) {
		this.song = song;
	}

	public Instrument getInstrument() {
		return instrument;
	}

	public void setInstrument(Instrument instrument) {
		this.instrument = instrument;
	}

}
 

Piano類

package SpringStudy.Model;


public class Piano {
	private String name="Piano";
	private String sound;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getSound() {
		return sound;
	}

	public void setSound(String sound) {
		this.sound = sound;
	}

}

package webMyBatis;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import SpringStudy.Model.Counter;

public class SpringTest {
	public static void main(String[] args) {
		//ApplicationContext ctx = new ClassPathXmlApplicationContext("spring/bean.xml");// 讀取bean.xml中的內容
		ApplicationContext annotationContext = new AnnotationConfigApplicationContext("SpringStudy");
		Counter c = annotationContext.getBean("counter", Counter.class);// 建立bean的引用物件
		System.out.println(c.getMultiplier());
		System.out.println(c.isEquals());
		System.out.println(c.getSong());
	        System.out.println(c.getInstrument().getName());
	}
}

注意：如果是在xml中配置beans和bean的話，或者使用自動掃描呼叫的話，程式碼為

ApplicationContext ctx = new ClassPathXmlApplicationContext("spring/bean.xml");// 讀取bean.xml中的內容
Counter c = ctx.getBean("counter", Counter.class);// 建立bean的引用物件

五、執行結果

12.0
false
Shake it Off
Piano