Spring基于java的配置

<context:component-scan
base-package="com.springinaction.springidol">
</context:component-scan>

package com.springinaction.springidol;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * 这个类是使用java来配置Spring的configuration类，@configuration标注了该类为配置类
 **/

@Configuration
public class SpringIdolConfig {

    
    @Bean
    //函数名就是bean的id
    public Performer duke(){
        //调用Juggler的构造方法即可，此处15相当于是通过构造器方法注入了值
        return new Juggler(15);
    }
    
    @Bean
    public Performer kenny(){
        Instrumentalist kenny = new Instrumentalist();
        //通过set方法注入值
        kenny.setSong("Jingle bell");
        return kenny;
    }
    
    @Bean
    public Poem sonnet29(){
        return new Sonnet29();
    }
    
    //在一个bean中注入另一个bean，sonnet29()方法返回的是上下文中的同一个实例
    @Bean
    public Performer poeticDuke(){
        //此处通过构造方法注入了一个bean的引用
        return new PoeticJuggler(sonnet29());
    }
    
    @Bean
    public Performer poeticDuke1(){
        
        PoeticJuggler poeticDuke1 = new PoeticJuggler();
        //此处通过setter方法注入了一个bean的引用
        poeticDuke1.setPoem(sonnet29());
        return poeticDuke1;
        
    }
}