📋 4. 의존 자동 주입

@Configuration
public class ApplicationContextTestResourceQualifier {

    @Bean
  	@Qualifier("defaultFile")
    public File defaultFile() {
        File defaultFile = new File("defaultFile.txt");
        return defaultFile;
    }
}

public class MemberListPrinter {

	private MemberDao memberDao;
	private MemberPrinter printer;

	public MemberListPrinter(MemberDao memberDao, MemberPrinter printer) {
		this.memberDao = memberDao;
		this.printer = printer;
	}
	
  @Autowired
  @Qualifier("printer")
	public void setMemberPrint(MemberPrinter printer) {
		this.printer = printer;
	}
}

public class MemberSummaryPrinter extends MemberPrinter {

	@Override
	public void print(Member member) {
		System.out.printf(
				"회원 정보: 이메일=%s, 이름=%s\n", 
				member.getEmail(), member.getName());
	}

}

@Configuration
public class AppCtx {
	// ...
	
	@Bean
	public MemberPrinter memberPrinter1() {
		return new MemberPrinter();
	}
	
	@Bean
	public MemberSummaryPrinter memberPrinter2() {
		return new MemberSummaryPrinter();
	}
}

	@Bean
	@Qualifier("printer")
	public MemberPrinter memberPrinter1() {
		return new MemberPrinter();
	}
	
	@Bean
	@Qualifier("summaryPrinter")
	public MemberSummaryPrinter memberPrinter2() {
		return new MemberSummaryPrinter();
	}

public class MemberListPrinter {

	private MemberDao memberDao;
	private MemberPrinter printer;

  // ...
	
	@Autowired
	public void setMemberPrinter(MemberSummaryPrinter printer) {
		this.printer = printer;
	}
}

public class MemberPrinter {
	private DateTimeFormatter dateTimeFormatter;
	
	public void print(Member member) {
		if (dateTimeFormatter == null) {
			System.out.printf(
					"회원 정보: 아이디=%d, 이메일=%s, 이름=%s, 등록일=%tF\n", 
					member.getId(), member.getEmail(),
					member.getName(), member.getRegisterDateTime());
		} else {
			System.out.printf(
					"회원 정보: 아이디=%d, 이메일=%s, 이름=%s, 등록일=%s\n", 
					member.getId(), member.getEmail(),
					member.getName(), 
					dateTimeFormatter.format(member.getRegisterDateTime()));
		}
	}
  
 	@Autowired
	public void setDateFormatter(DateTimeFormatter dateTimeFormatter) {
		this.dateTimeFormatter = dateTimeFormatter;
	}

 // ...

@Autowired(required = false)
public void setDateFormatter(DateTimeFormatter dateTimeFormatter) {
  this.dateTimeFormatter = dateTimeFormatter;
}

@Autowired
public void setDateFormatter(Optional<DateTimeFormatter> formatterOpt) {
	if (formatterOpt.isPresent()) {
		this.dateTimeFormatter = formatterOpt.get();
	} else {
   	this.dateTimeFormatter = null;
	}
}

@Autowired
public void setDateFormatter(@Nullable DateTimeFormatter dateTimeFormatter) {
	this.dateTimeFormatter = dateTimeFormatter;
}

public class MemberPrinter {
	private DateTimeFormatter dateTimeFormatter;
	
	public MemberPrinter() {
		dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy년 MM월 dd일");
	}
	
	public void print(Member member) {
		if (dateTimeFormatter == null) {
			System.out.printf(
					"회원 정보: 아이디=%d, 이메일=%s, 이름=%s, 등록일=%tF\n", 
					member.getId(), member.getEmail(),
					member.getName(), member.getRegisterDateTime());
		} else {
			System.out.printf(
					"회원 정보: 아이디=%d, 이메일=%s, 이름=%s, 등록일=%s\n", 
					member.getId(), member.getEmail(),
					member.getName(), 
					dateTimeFormatter.format(member.getRegisterDateTime()));
		}
	}
	
	@Autowired(required = false)
	public void setDateFormatter(DateTimeFormatter dateTimeFormatter) {
		this.dateTimeFormatter = dateTimeFormatter;
	}
}