public class DvdPlayMissionImpossible {

    private MissionImpossibleCd missionImpossibleCd;

    public DvdPlayMissionImpossible(){
        this.missionImpossibleCd = new MissionImpossibleCd(); // 紧耦合
    }

    public void play(){
        System.out.println("一台只能看" + missionImpossibleCd.getCompactDiskName() + "的DVD");
    }
}

public class DvdPlayFurious {

    private FuriousCd furiousCd;

    public DvdPlayFurious(){
        this.furiousCd = new FuriousCd(); // 紧耦合
    }

    public void play(){
        System.out.println("一台只能看" + furiousCD.getCompactDiskName() + "的DVD");
    }
}


public class MissionImpossibleCd {

    public String getCompactDiskName(){
        return "碟中谍";
    }
}

public class FuriousCd {

    public String getCompactDiskName(){
        return "速度与激情";
    }
}

// Traditional Way.
@Test
public void dvdPlayerMissionImpossibleTest(){
    DvdPlayMissionImpossible dvdPlayMissionImpossible = new DvdPlayMissionImpossible();
    DvdPlayFurious           dvdPlayFurious           = new DvdPlayFurious();
    dvdPlayMissionImpossible.play(); // 一台只能看碟中谍的DVD
    dvdPlayFurious.play();           // 一台只能看速度与激情的DVD
}

public interface CompactDisk {
    String getCDName();
}

@Component
public class MissionImpossible implements CompactDisk {

    @Override
    public String getCDName() {
        return "碟中谍";
    }
}

@Component
public class Furious implements CompactDisk{

    @Override
    public String getCDName() {
        return "速度与激情";
    }
}

public interface MediaPlayer {
    void play();
}

@Component
public class DvdPlayer implements MediaPlayer {

    @Autowired
    @Qualifier("missionImpossible")
    private CompactDisk cd;

    @Override
    public void play() {
        System.out.println("一台可以看" + cd.getCDName() + "的DVD");
    }
}

@Component
public class VCDPlayer implements MediaPlayer {

    @Autowired
    @Qualifier("furious")
    private CompactDisk cd;

    @Override
    public void play() {
        System.out.println("一台可以看" + cd.getCDName() + "的VCD");
    }
}

@Autowired
DvdPlayer dvdPlayer;

@Autowired
VCDPlayer vcdPlayer;

// DI Way.
@Test
public void dvdAndVcdPlayerTest(){
    dvdPlayer.play(); // 一台可以看碟中谍的DVD
    vcdPlayer.play(); // 一台可以看速度与激情的VCD
}