【Spring】28、Spring中基于Java的配置@Configuration和@Bean用法.代替xml配置文件

Spring中为了减少xml中配置，可以生命一个配置类（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="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>

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

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类

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;
}

}

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

出处：http://blog.csdn.net/vvhesj/article/details/47661001