最近在项目开发过程中关注到一个依赖注入的写法差异，因为本人代码上有点强迫症，看到这种不同人不一样的写法，特意了解了一下，但是依然有部分疑惑未解。

        两种写法：(就是传说中最常见的属性注入和构造函数注入)

@Service
public class ContactCodeInfoService {
    @Autowired
    private ContactCodeInfoMapper contactCodeInfoMapper;
    @Autowired
    private CorpStaffMapper corpStaffMapper;

    、、、、、
}

@Service
public class CrAppService {
    private final CrAppRepository crAppRepository;

    public CrAppService(CrAppRepository crAppRepository) {
        this.crAppRepository = crAppRepository;
    }

    、、、、、
}

Spring官方推荐的是构造函数，并不推荐属性注入的方式

不推荐使用属性注入的理由的却很充分。 但是当采用构造函数注入会遇到代码很不简洁的问题，一旦需要注入的属性达到了四五个，整个构造函数就会显得很臃肿。

@Service
public class SiteCheckServiceImpl implements SiteCheckService {

    private final SitePageSpiderService sitePageSpiderService;
    private final SitePageAnalyzeService sitePageAnalyzeService;
    private final CheckService checkService;
    private final LogEventPublisher processLogEventPublisher;

    
    public SiteCheckServiceImpl(SitePageSpiderService sitePageSpiderService,
                                SitePageAnalyzeService sitePageAnalyzeService,
                                CheckService checkService,
                                LogEventPublisher processLogEventPublisher) {
        this.sitePageSpiderService = sitePageSpiderService;
        this.sitePageAnalyzeService = sitePageAnalyzeService;
        this.checkService = checkService;
        this.processLogEventPublisher = processLogEventPublisher;
    }
    
    、、、、、、
}

遇到这个问题又继续查略一些资料，结果表示可以通过lombok的@AllArgsConstructor来简化代码，让代码看起来比较整洁

@Service
@AllArgsConstructor
public class SiteCheckServiceImpl implements SiteCheckService {

    private final SitePageSpiderService sitePageSpiderService;
    private final SitePageAnalyzeService sitePageAnalyzeService;
    private final CheckService checkService;
    private final LogEventPublisher processLogEventPublisher;

    、、、、、
}

这样看起来也确实简洁了很多，但是当遇到有继承的情况下，就显得有些顾此失彼了

public abstract class BaseCheckProviderFactory {
    private final ProviderLimitStatus<String> providerLimitStatus;
    private final ProviderStrategy<ProviderBean> providerStrategy;
    private final Map<String, RateLimiter> providerRateLimiterMap;
    private final AppConfigService appConfigService;

    public BaseCheckProviderFactory(ProviderLimitStatus<String> providerLimitStatus,
                                    ProviderStrategy<ProviderBean> providerStrategy,
                                    Map<String, RateLimiter> providerRateLimiterMap,
                                    AppConfigService appConfigService) {
        this.providerLimitStatus = providerLimitStatus;
        this.providerStrategy = providerStrategy;
        this.providerRateLimiterMap = providerRateLimiterMap;
        this.appConfigService = appConfigService;
    }

    、、、、、、
}

@Component
public class TextCheckProviderFactory extends BaseCheckProviderFactory<TextCheckRequest, TextCheckResponse> {

    private final CheckLibraryService<TextCheckRequest, TextCheckResponse> textCheckLibraryService;

    
    public TextCheckProviderFactory(ProviderLimitStatus<String> providerLimitStatus,
                                    ProviderStrategy<ProviderBean> providerStrategy,
                                    Map<String, RateLimiter> providerRateLimiterMap,
                                    AppConfigService appConfigService,
                                    CheckLibraryService<TextCheckRequest, TextCheckResponse> textCheckLibraryService) {

        super(providerLimitStatus, providerStrategy, providerRateLimiterMap, appConfigService);
        this.textCheckLibraryService = textCheckLibraryService;
    }
    、、、、、、
}

这里有几种加lombok的方式：

1、父类和子类都加上@AllArgsConstructor，但是子类的构造函数要求父类需要有个无参构造函数

2、父类和子类都加上@AllArgsConstructor，同时父类加上@NoArgsConstructor，但是会出现父类的final属性没有在无参构造时没有初始化的问题。

后续的探索持续跟进中。。。