java - 如何在带有注释的 Spring 中按名称 Autowiring ？

Question

我定义了几个相同类的bean:

  @Bean
  public FieldDescriptor fullSpotField() {
     FieldDescriptor ans = new FieldDescriptor("full_spot", String.class);
     return ans;
  }

  @Bean
  public FieldDescriptor annotationIdField() {
     FieldDescriptor ans = new FieldDescriptor("annotationID", Integer.class);
     return ans;
  }

因此当我自动连接它们时

   @Autowired
   public FieldDescriptor fullSpotField;

   @Autowired
   public FieldDescriptor annotationIdField;

我遇到了异常

NoUniqueBeanDefinitionException: No qualifying bean of type [...FieldDescriptor] is defined: expected single matching bean but found ...

如何在 XML 配置中尽可能按名称 Autowiring ？

Answer 1

你可以使用@Qualifier来解决。

在你的情况下，你可以:

 @Bean(name="fullSpot")
 // Not mandatory. If not specified, it takes the method name i.e., "fullSpotField" as qualifier name.
  public FieldDescriptor fullSpotField() {
     FieldDescriptor ans = new FieldDescriptor("full_spot", String.class);
     return ans;
  }

  @Bean("annotationIdSpot")
  // Same as above comment.
  public FieldDescriptor annotationIdField() {
     FieldDescriptor ans = new FieldDescriptor("annotationID", Integer.class);
     return ans;
  }

随后您可以使用以下方法进行注入(inject):

   @Autowired
   @Qualifier("fullSpot")
   public FieldDescriptor fullSpotField;

   @Autowired
   @Qualifier("annotationIdSpot")
   public FieldDescriptor annotationIdField;