使用@Import和@ImportResource进行Spring Java config和xml的混合配置
最近在看《Spring in Action 4th》，讲到JavaConfig的@Import和@ImportResource的使用，于是照着例子做了个小demo，加深自己的印象。在Spring中配置有xml和JavaConfig的配置方式，相比来说，使用JavaConfig的方式配置会更利于管理，类型安全。
demo项目结构(Maven约定)：
├── pom.xml
└── src
├── main
│ ├── java
│ │ └── com
│ │ └── jiaobuchong
│ │ ├── config
│ │ │ ├── CDConfig.java
│ │ │ ├── CDPlayerConfig.java
│ │ │ └── SoundSystemConfig.java
│ │ ├── dao
│ │ │ └── CompactDisc.java
│ │ │ └── MediaPlayer.java
│ │ └── soundsystem
│ │ ├── BlankDisc.java
│ │ ├── CDPlayer.java
│ │ └── SgtPeppers.java
│ └── resources
│ └── cons-injec.xml
└── test
└── java
└── com
└── jiaobuchong
├── soundsystem
├── CDPlayerTest.javadao下两个interface：
CompactDisc.java：
package com.jiaobuchong.dao;
public interface CompactDisc {
void play();
}MediaPlayer.java
package com.jiaobuchong.dao;
public interface MediaPlayer {
void play();
}soundsystem包下的interface实现类：
BlankDisc.java：
package com.jiaobuchong.soundsystem;
import com.jiaobuchong.dao.CompactDisc;
import java.util.List;
public class BlankDisc implements CompactDisc {
private String title;
private String artist;
private List tracks;
public BlankDisc(String title, String artist, List tracks) {
this.title = title;
this.artist = artist;
this.tracks = tracks;
}
public void play() {
System.out.println("Playing " + title + " by " + artist);
for (String track : tracks) {
System.out.println("-Track: " + track);
}
}
} CDPlayer.java：
package com.jiaobuchong.soundsystem;
import com.jiaobuchong.dao.MediaPlayer;
import org.springframework.beans.factory.annotation.Autowired;
public class CDPlayer implements MediaPlayer {
private CompactDisc cd;
public CDPlayer(CompactDisc cd) {
this.cd = cd;
}
public void play() {
cd.play();
}
}
SgtPeppers.java：
package com.jiaobuchong.soundsystem;
import com.jiaobuchong.dao.CompactDisc;
import org.springframework.stereotype.Component;
public class SgtPeppers implements CompactDisc {
private String title = "Sgt. Pepper's Lonely Hearts Club Band";
private String artist = "The Beatles";
public void play() {
System.out.println("Playing " + title + " by " + artist);
}
}config包下的三个配置类
CDConfig.java：
package com.jiaobuchong.config;
import com.jiaobuchong.dao.CompactDisc;
import com.jiaobuchong.soundsystem.SgtPeppers;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration // @Configuration注解表示定义一个配置类
public class CDConfig {
// 方法名heyGirl即是bean的name
@Bean // 将SgtPeppers注册为 SpringContext中的bean
public CompactDisc heyGirl() {
return new SgtPeppers(); // CompactDisc类型的
}
}@Bean注解等同于xml的配置：
<beans>
<bean name="heyGirl" class="com.jiaobuchong.soundsystem.SgtPeppers" />
beans>CDPlayerConfig.java：
package com.jiaobuchong.config;
import com.jiaobuchong.dao.CompactDisc;
import com.jiaobuchong.soundsystem.CDPlayer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
@Configuration
@Import(CDConfig.class) //导入CDConfig的配置
public class CDPlayerConfig {
@Bean(name = "cDPlayer")
public CDPlayer cdPlayer(CompactDisc heyGirl) {
/* 这里注入的bean是
上面CDConfig.java中的name为heyGirl的CompactDisc类型的bean*/
return new CDPlayer(heyGirl);
}
}这里的注解@Bean等同于xml配置的元素，
name="cDPlayer" class="com.jiaobuchong.soundsystem.CDPlayer">
<property name="cd" ref="heyGirl" />
SoundSystemConfig.java：
package com.jiaobuchong.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.ImportResource;
@Configuration
@Import(CDPlayerConfig.class)
@ImportResource("classpath:cons-injec.xml") //导入xml配置项
public class SoundSystemConfig {
}@ImportResource等同于xml配置：
<import resource="cons-injec.xml" />xml配置文件
cons-injec.xml：
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:c="http://www.springframework.org/schema/c"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
">
<bean id="compactDisc"
class="com.jiaobuchong.soundsystem.BlankDisc"
c:_0="Sgt. Pepper's Lonely Hearts Club Band"
c:_1="The Beatles">
<constructor-arg>
<list>
<value>Sgt. Pepper's Lonely Hearts Club Bandvalue>
<value>With a Little Help from My Friendsvalue>
<value>Lucy in the Sky with Diamondsvalue>
<value>Getting Bettervalue>
<value>Fixing a Holevalue>
list>
constructor-arg>
bean>
beans>测试类
CDPlayerTest.java：
package com.jiaobuchong.soundsystem;
import com.jiaobuchong.config.CDConfig;
import com.jiaobuchong.config.CDPlayerConfig;
import com.jiaobuchong.dao.CompactDisc;
import com.jiaobuchong.dao.MediaPlayer;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
/*
CDPlayerTest takes advantage of Spring’s SpringJUnit4ClassRunner to have a Spring application
context automatically created when the test starts. And the @Context-Configuration annotation
tells it to load its configuration from the CDPlayerConfig class.
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = CDConfig.class)
public class CDPlayerTest {
@Autowired
private MediaPlayer mediaPlayer;
@Autowired
@Qualifier("heyGirl")
private CompactDisc keyGirl;
@Autowired
@Qualifier("compactDisc")
private CompactDisc cd;
@Test
public void beanTest() {
mediaPlayer.play();
cd.play();
keyGirl.play();
}
}
看完这个demo代码，基本上@Import和ImportResource的作用也就了然于胸了，以后妈妈再也不担心我的Spring配置了。更多细节请移步《Spring in Action 4th》。