建立可被發現的Bean:

        建立CD介面:

package main.java.Demo1;

/**
 * @author [email protected]
 * @date 18-4-15 下午6:53
 */

public interface CompactDisc {
    void play();
}

package main.java.Demo1;

import org.springframework.stereotype.Component;

/**
 * @author [email protected]
 

 * @date 18-4-15 下午8:50
 */

public class BeatlesCD implements CompactDisc {
    @Override
    public void play() {
        System.out.println("Playing Beatles");
    }
}

        建立CDPlayer類引用BeatlesCD例項:

package main.java.Demo1;  
  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.stereotype.Component;  
  
/** 
 * @author 
 
[email protected] 
 * @date 18-4-15 下午9:16 
 */  
  
public class CDPlayer {  
    private CompactDisc cd;  
  
    public CDPlayer(CompactDisc cd){  
        this.cd = cd;  
    }  
  
    public void play(){  
        cd.play();  
    }  
}  

       JavaConfig程式碼如下:

package main.java.Demo1;

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

/**
 * @author 
 
[email protected]
 * @date 18-4-16 上午8:53
 */

@Configuration
public class CompactDiskConfig2 {
    @Bean
    public CompactDisc beatlesCD(){
        return new BeatlesCD();
    }

    @Bean
    public CDPlayer cdPlayer(){
        return new CDPlayer(beatlesCD());
    }
}

package main.java.Demo1;

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;

import static org.junit.Assert.assertNotNull;

/**
 * @author [email protected]
 * @date 18-4-15 下午6:56
 */

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = CompactDiskConfig2.class)
public class CDPlayerTest {
    @Autowired
    private BeatlesCD cd;

    @Test
    public void cdShouldNotNull(){
        assertNotNull(cd);
    }

    @Autowired
    private CDPlayer cdPlayer;

    @Test
    public void cdPlayerPlay(){
        cdPlayer.play();
    }
}

四月 16, 2018 8:56:35 上午 org.springframework.test.context.support.DefaultTestContextBootstrapper getDefaultTestExecutionListenerClassNames
資訊: Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener]
四月 16, 2018 8:56:36 上午 org.springframework.test.context.support.DefaultTestContextBootstrapper getTestExecutionListeners
資訊: Using TestExecutionListeners: [org.springframework.test[email protected]38082d64, org.springframewor[email protected]dfd3711, org.springfra[email protected]42d3bd8b, org.springframew[email protected]26ba2a48, org.sp[email protected]5f2050f6]
四月 16, 2018 8:56:36 上午 org.springframework.context.support.GenericApplicationContext prepareRefresh
資訊: Refreshing [email protected]82f6ef: startup date [Mon Apr 16 08:56:36 CST 2018]; root of context hierarchy
四月 16, 2018 8:56:38 上午 org.springframework.context.support.GenericApplicationContext doClose
資訊: Closing [email protected]82f6ef: startup date [Mon Apr 16 08:56:36 CST 2018]; root of context hierarchy

Process finished with exit code 0

四月 16, 2018 8:58:21 上午 org.springframework.test.context.support.DefaultTestContextBootstrapper getDefaultTestExecutionListenerClassNames
資訊: Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener]
四月 16, 2018 8:58:21 上午 org.springframework.test.context.support.DefaultTestContextBootstrapper getTestExecutionListeners
資訊: Using TestExecutionListeners: [org.springframework.test[email protected]38082d64, org.springframewor[email protected]dfd3711, org.springfra[email protected]42d3bd8b, org.springframew[email protected]26ba2a48, org.sp[email protected]5f2050f6]
四月 16, 2018 8:58:22 上午 org.springframework.context.support.GenericApplicationContext prepareRefresh
資訊: Refreshing [email protected]82f6ef: startup date [Mon Apr 16 08:58:22 CST 2018]; root of context hierarchy
Playing Beatles
四月 16, 2018 8:58:23 上午 org.springframework.context.support.GenericApplicationContext doClose
資訊: Closing [email protected]82f6ef: startup date [Mon Apr 16 08:58:22 CST 2018]; root of context hierarchy

Process finished with exit code 0

        成功輸出"Playing Beatles"(但後面多了一些關閉框架的東西,暫時不懂!),測試成功.

補充:

        [email protected](name="name")可以為Bean命名.

        2.上面設定CDPlayer Bean時還可以用下面這種更簡單的方式:

@Bean
    public CDPlayer cdPlayer(CompactDisc compactDisc){
        return new CDPlayer(compactDisc);
    }

        這種方法可以不明確地引用CompactCD的@Bean方法;這種方法也是最佳的選擇,因為它不會要求將CompactCD宣告到同一個配置類當中,這裡甚至沒有要求CompactCD必須在JavaConfig中宣告,實際上它可以通過元件掃描功能或自動發現或者通過XML進行配置.

        3.上面是使用了CDPlayer的構造器實現了DI功能,但完全可以使用其他風格的DI配置,比如Setter方法,如下:

@Bean
    public CDPlayer cdPlayer(CompactDisc compactDisc){
        CDPlayer cdPlayer = new CDPlayer();
        cdPlayer.setCd(compactDisc);
        return cdPlayer;
    }