[英]Guice - Multiple provider methods for same return types
在我的模塊中:
@Provides
@Singleton
public ExecutorService provideExecutorService(){
return new ExecutorService(config);
}
在我的課上:
@Inject
private ExecutorService executorService;
現在,我需要兩個具有不同配置的ExecutorService實例:
@Provides
@Singleton
public ExecutorService provideExecutorServiceA(){
return new ExecutorService(configA);
}
@Provides
@Singleton
public ExecutorService provideExecutorServiceB(){
return new ExecutorService(configB);
}
如果我想為班上用configB創建的ExecutorService注入ExecutorService,我該怎么做?
您可以使用綁定注釋 :
@Provides
@Singleton
@Priority(Priority.Level.HIGH)
public static ReportingDal createHighPriorityReportingDal(DataSource dataSource,
DatabaseType databaseType,
ReportingQueryGenerator queryGenerator)
{
return new ReportingDalImpl(dataSource, databaseType, Queue.DEFAULT, queryGenerator);
}
@Provides
@Singleton
@Priority(Priority.Level.LOW)
public static ReportingDal createLowPriorityReportingDal(DataSource dataSource,
DatabaseType databaseType,
ReportingQueryGenerator queryGenerator)
{
return new ReportingDalImpl(dataSource, databaseType, Queue.MAINTENANCE, queryGenerator);
}
@Priority批注如下所示:
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD })
@BindingAnnotation
public @interface Priority
{
Level value();
public enum Level
{
LOW,
HIGH
}
}
請注意,如果您不想實現自定義注釋,則可以使用內置Guice的@Named注釋 。 然后,您可以像下面這樣在類中使用它:
@Inject
public ReportingJob(@Priority(Priority.Level.LOW) ReportingDal dal)
{
this.dal = dal;
}
編輯
或者,如果您通過私有字段進行注入:
@Inject
@Priority(Priority.Level.LOW)
private ReportingDal dal;
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.