Spring 3.0 It's such a simple reading note.

In general, most of the beans in the spring container are single-instance, so it is generally not necessary to specify a name for the bean through the Value property of the annotation @repository, @Service, @Component, etc. There is no need to use @qualifier to inject by name.

@Autowired are used in the following ways:

Labeling a class variable

@Autowired

Private Logdao Logdao;

Labeling A class method

To label a collection class (a property of a class)

@Autowired

Private list<plugin> plugins;

@Autowired
@Qualifier ("Testing")
Private Foodao Foodao;

Foodao corresponding Beanid is not necessarily foodao, there may be other.

Foodao has two implementation classes: Stubfoodao and Wjfoodao, see below

@Qualifier ("okdahello")
Private Foodao Foodao;

The Okdahello above can correspond to

@Repository ("Okdahello")
@Qualifier ("Testing")
public class Wjfoodao implements Foodao

can also correspond to

@Repository
@Qualifier ("Testing")
@Qualifier ("Okdahello")
public class Wjfoodao implements Foodao

@Qualifier ("Okdahello") or @Repository ("Okdahello") is all OK
@Repository ("Okdahello") can change Beanid.

Spring 3.0 It's such a simple reading note.