spring中为了减少xml中配置，可以声明一个配置类（例如SpringConfig）来对bean进行配置。
一、首先，需要xml中进行少量的配置来启动Java配置:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns
<context:component-scan base-package="SpringStudy.Model">
</context:component-scan>
</beans>二、定义一个配置类
用@Configuration注解该类，等价 与XML中配置beans；用@Bean标注方法等价于XML中配置bean。
代码如下：
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());
}
}三、基础类代码
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类
package SpringStudy.Model;
public class Piano {
private String name="Piano";
private String sound;
public String getName() {
return name;
}
public void setName(String name) {
= name;
}
public String getSound() {
return sound;
}
public void setSound(String sound) {
this.sound = sound;
}
}四、调用测试类
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");// 读取bean.xml中的内容
ApplicationContext annotationContext = new AnnotationConfigApplicationContext("SpringStudy");
Counter c = annotationContext.getBean("counter", Counter.class);// 创建bean的引用对象
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的话，或者使用自动扫描调用的话，代码为
ApplicationContext ctx = new ClassPathXmlApplicationContext("spring/bean.xml");// 读取bean.xml中的内容
Counter c = ctx.getBean("counter", Counter.class);// 创建bean的引用对象
五、运行结果
12.0
false
Shake it Off
Piano
