Question

我在从DefaultConfigurationService类扩展的Spring bean abstract初始化时遇到问题。我完全陷入困境。

类层次结构如下：

public interface ConfigurationService {
    TaxPayer getTaxPayer();
}

这个类被认为对需要初始化的服务很有用：

public abstract class BaseInitializationAwareService {

    private boolean initialized = false;

    public abstract void initialize();

    protected void checkInitialization() {
        if (!initialized) {
            initialize();
        }
    }

    protected void setInitialized() {
        this.initialized = true;
    }
}

此类充当配置服务的基类。

public abstract class BaseConfigurationService extends BaseInitializationAwareService implements ConfigurationService {


}

使用这个充当配置服务的bean是一个问题：

    public class DefaultConfigurationService extends BaseConfigurationService {

        private TaxPayerService taxPayerService;

        @Autowired
        public void setTaxPayerService(TaxPayerService taxPayerService) {
            Assert.notNull(taxPayerService);
            this.taxPayerService = taxPayerService;
        }

public void initialize() {
        Optional<TaxPayer> dbtaxPayer = taxPayerService.getActiveTaxPayer();
        if (!dbtaxPayer.isPresent()) {
            throw new IllegalStateException("Tax payer setting not found!");
        }
        this.taxPayer = dbtaxPayer.get();
        setInitialized();
    }

    // the rest omitted...
    }

当我创建DefaultConfigurationService bean时：

@Bean
    public BaseConfigurationService configurationService() {
        DefaultConfigurationService configurationService = new DefaultConfigurationService();
        configurationService.initialize();
        return configurationService;
    }

然后taxPayerService中的DefaultConfigurationService为空 - 似乎没有自动装配。

可以与DefaultConfigurationService从抽象类扩展的事实联系起来吗？

TaxPayer服务bean：

@Bean
    public TaxPayerService taxPayerService() {
        DatabaseTaxPayerService taxPayer = new DatabaseTaxPayerService();
        return taxPayer;
    }

这个bean可能从未初始化 ...

这是一个例外：

org.springframework.beans.factory.UnsatisfiedDependencyException：创建名为'webSecurityConfig.ApiSecurity'的bean时出错：通过方法表达不满意的依赖性 'setContentNegotationStrategy'参数0;嵌套异常是 org.springframework.beans.factory.UnsatisfiedDependencyException：使用名称创建bean时出错 'org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration'：通过方法'setConfigurers'表示不满意的依赖参数0;嵌套异常是 org.springframework.beans.factory.UnsatisfiedDependencyException：创建名为'passwordRecoverController'的bean时出错：不满意通过方法'setUserService'参数0表示的依赖关系; 嵌套异常是 org.springframework.beans.factory.UnsatisfiedDependencyException：创建名为'defaultUserService'的bean时出错：不满意通过方法'setNotificationService'参数表示的依赖关系 0;嵌套异常是 org.springframework.beans.factory.UnsatisfiedDependencyException：创建名为'notificationService'的bean时出错：不满意通过方法'setConfigurationService'表示的依赖关系参数0;嵌套异常是 org.springframework.beans.factory.BeanCreationException：错误在类路径中定义名为'configurationService'的bean resource [com.example.config / AppConfig.class]：Bean实例化via 工厂方法失败;嵌套异常是 org.springframework.beans.BeanInstantiationException：失败实例化[com.example.services.BaseConfigurationService]：Factory 方法'configurationService'抛出异常;嵌套异常是显示java.lang.NullPointerException

例如，需要BaseConfigurationService的bean：

    public class EmailNotificationService extends BaseService implements NotificationService {

        private BaseConfigurationService configurationService;

@Autowired
    public void setConfigurationService(BaseConfigurationService configurationService) {
        Assert.notNull(configurationService);
        this.configurationService = configurationService;
    }

    // the rest omitted... 
    }

#update 1

Bean初始化示例，内部依赖于另一个bean：

@Bean
    public TransactionDataService transactionDataService() {
        return new DefaultTransactionDataService();
    }

和DefaultTransactionDataService：

public class DefaultTransactionDataService implements TransactionDataService {
    private PrivateKeyService privateKeyService;

    @Autowired
    public void setPrivateKeyService(PrivateKeyService privateKeyService) {
        Assert.notNull(privateKeyService);
        this.privateKeyService = privateKeyService;
    }
}

和bean依赖

@Bean
    public PrivateKeyService privateKeyService() {
        return new DefaultPrivateKeyAwareService();
    }

有效。

Answer 1

它与您对Spring的指令有关，如何初始化bean：

@Bean用于显式声明单个bean，而不是让Spring像上面那样自动执行它。它将bean的声明与类定义分离，并允许您根据自己的选择创建和配置bean。

因此，当您手动创建类的实例时，您还必须手动设置所有类字段。

可以这样做：

@Bean
public BaseConfigurationService configurationService() {
    DefaultConfigurationService configurationService = new DefaultConfigurationService();
    configurationService.setTaxPayerService(taxPayerService());
    configurationService.initialize();
    return configurationService;
}

或者将依赖项直接移动到构造函数，因此DefaultConfigurationService的依赖关系会更加明显：

@Bean
public BaseConfigurationService configurationService() {
    DefaultConfigurationService configurationService = new DefaultConfigurationService(taxPayerService());
    configurationService.initialize();
    return configurationService;
}

Good description

Spring Bean未自动装配

1 个答案: