Google Guice之注入方式

标签：google   guice   inject   

赋值给final字段。

public class RealBillingService implements BillingService {
  private final CreditCardProcessor processorProvider;
  private final TransactionLog transactionLogProvider;

  @Inject
  public RealBillingService(CreditCardProcessor processorProvider,
      TransactionLog transactionLogProvider) {
    this.processorProvider = processorProvider;
    this.transactionLogProvider = transactionLogProvider;
  }
}

public class PayPalCreditCardProcessor implements CreditCardProcessor {

  private static final String DEFAULT_API_KEY = "development-use-only";

  private String apiKey = DEFAULT_API_KEY;

  @Inject
  public void setApiKey(@Named("PayPal API key") String apiKey) {//该方法会被Guice调用并注入值
    this.apiKey = apiKey;
  }
}

public class DatabaseTransactionLogProvider implements Provider<TransactionLog> {
  @Inject Connection connection;

  public TransactionLog get() {
    return new DatabaseTransactionLog(connection);
  }
}

public class PayPalCreditCardProcessor implements CreditCardProcessor {
  private static final String SANDBOX_API_KEY = "development-use-only";

  private String apiKey = SANDBOX_API_KEY;

  @Inject(optional=true)
  public void setApiKey(@Named("PayPal API key") String apiKey) {
    this.apiKey = apiKey;
  }
}

@Inject(optional=true) Date launchDate;//launchDate依赖会进行注入

public static void main(String[] args) {
    Injector injector = Guice.createInjector(...);

    CreditCardProcessor creditCardProcessor = new PayPalCreditCardProcessor();//手动创建而不是从容器中获取
    injector.injectMembers(creditCardProcessor);//会为creditCardProcessor中需要注入的成员进行注入
}

@Override public void configure() {
	requestStaticInjection(ProcessorFactory.class);
	...
}
class ProcessorFactory {
  @Inject static Provider<Processor> processorProvider;

  /**
   * @deprecated prefer to inject your processor instead.
   */
  @Deprecated
  public static Processor getInstance() {
    return processorProvider.get();
  }
}

七、自动注入(Automatic Injection)
以下情形Guice会进行自动注入:
a.传递给toInstance()语句的实例
b.传递toProvider()语句的Provider对象，这些对象会在注入器创建时进行注入.

Google Guice之注入方式

标签：google   guice   inject   

原文地址：http://blog.csdn.net/xtayfjpk/article/details/40708021