java中配置bean_Spring中基于Java的配置@Configuration和@Bean用法
Spring中為了減少xml中配置，可以聲明一個配置類(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:
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">
<?xml version="1.0" encoding="UTF-8"?>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">
二、定義一個配置類
用@Configuration注解該類，等價 與XML中配置beans；用@Bean標注方法等價于XML中配置bean。
代碼如下：
packageSpringStudy;
importorg.springframework.context.annotation.Bean;
importorg.springframework.context.annotation.Configuration;
importSpringStudy.Model.Counter;
importSpringStudy.Model.Piano;
@Configuration
publicclassSpringConfig?{
@Bean
publicPiano?piano(){
returnnewPiano();
}
@Bean(name?="counter")
publicCounter?counter(){
returnnewCounter(12,"Shake?it?Off",piano());
}
}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、基礎類代碼
Counter：
packageSpringStudy.Model;
publicclassCounter?{
publicCounter()?{
}
publicCounter(doublemultiplier,?String?song,Instrument?instrument)?{
this.multiplier?=?multiplier;
this.song?=?song;
this.instrument=instrument;
}
privatedoublemultiplier;
privateString?song;
@Resource
privateInstrument?instrument;
publicdoublegetMultiplier()?{
returnmultiplier;
}
publicvoidsetMultiplier(doublemultiplier)?{
this.multiplier?=?multiplier;
}
publicString?getSong()?{
returnsong;
}
publicvoidsetSong(String?song)?{
this.song?=?song;
}
publicInstrument?getInstrument()?{
returninstrument;
}
publicvoidsetInstrument(Instrument?instrument)?{
this.instrument?=?instrument;
}
}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
packageSpringStudy.Model;
publicclassPiano?{
privateString?name="Piano";
privateString?sound;
publicString?getName()?{
returnname;
}
publicvoidsetName(String?name)?{
this.name?=?name;
}
publicString?getSound()?{
returnsound;
}
publicvoidsetSound(String?sound)?{
this.sound?=?sound;
}
}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、調用測試類
packagewebMyBatis;
importorg.springframework.context.ApplicationContext;
importorg.springframework.context.annotation.AnnotationConfigApplicationContext;
importSpringStudy.Model.Counter;
publicclassSpringTest?{
publicstaticvoidmain(String[]?args)?{
//ApplicationContext?ctx?=?new?ClassPathXmlApplicationContext("spring/bean.xml");//?讀取bean.xml中的內容
ApplicationContext?annotationContext?=?newAnnotationConfigApplicationContext("SpringStudy");
Counter?c?=?annotationContext.getBean("counter",?Counter.class);//?創建bean的引用對象
System.out.println(c.getMultiplier());
System.out.println(c.isEquals());
System.out.println(c.getSong());
System.out.println(c.getInstrument().getName());
}
}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);// 創建bean的引用對象
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的話，或者使用自動掃描調用的話，代碼為
ApplicationContext ctx = new ClassPathXmlApplicationContext("spring/bean.xml");// 讀取bean.xml中的內容
Counter c = ctx.getBean("counter", Counter.class);// 創建bean的引用對象
五、運行結果
12.0
false
Shake it Off
Piano
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