Basic annotaions to describe a bean:

| Annotation | Meaning                                             |+------------+-----------------------------------------------------+| @Component | generic stereotype for any Spring-managed component || @Repository| stereotype for persistence layer                    || @Service   | stereotype for service layer                        || @Controller| stereotype for presentation layer (spring-mvc)      |

The above annotations can have a optional element: String value.  The value may indicate a suggestion for a logical component name, to be turned into a Spring bean in case of an autodetected component.

@Autowired

Marks a constructor, field, setter method or config method as to be autowired by Spring's dependency injection facilities.

If there'are multiple implementation, you can use a Map to store the injected implementations.

If you have an interface named Example

public interface Example {}

And two implementations:

@Component("foo")public class FooExample implements Example {}@Component("bar")public class BarExample implements Example {}

You can have a map of Example beans injected:

@Componentpublic class ExampleConsumer {    private final Map
    
      examples;    @Autowired    public ExampleConsumer(Map
     
       examples) {        this.examples = examples;    }}
     
    

In this case the map will contain two entries:

• "foo" -> FooExample instance

• "bar" -> BarExample instance

@Qualifier

Use with @AutowiredThis annotation may be used on a field or parameter as a qualifier for candidate beans when autowiring. It may also be used to annotate other custom annotations that can then in turn be used as qualifiers.

spring @Autowired @Qualifier @Resource

@Autowired: inject by type defaultly;

@Resource： inject by name defaultly.

Spring Injection with @Resource, @Autowired and @Inject

Annotations

For example:

package com.sourceallies.person;...("personBean")@Component@Qualifier("personBean")public class Person implements Party { }

In this test I use a ‘@Qualifier’ annotation to point to the qualified name of the ‘Person’ component.

@Resource@Qualifier("personBean")private Party party;

@Autowired@Qualifier("personBean")private Party party;

@Inject@Qualifier("personBean")private Party party;

All of these annotations inject the ‘Person’ bean.

To add List of Beans

In this test I inject a list of beans.

@Resourceprivate List
        
          parties;
        

@Autowiredprivate List
        
          parties;
        

@Injectprivate List
        
          parties;