Spring's four basic annotations annotation (control layer, business layer, persistence layer) @Component, @

Four basic annotations in SPRINGMVC:

@Component, @Repository @Service, @Controller

Look at the literal meaning, easy but not out of three of them:

@Controller Control layer, that's our action layer.

@Service The business Logic layer, which is our service or manager layer

@Repository Persistence layer, which is what we often call the DAO layer

and @Component (literally a component), it's used when you can't decide which layer to use.

In fact, these four annotations have the same effect, and spring will load them as a bean that needs to be injected into the context;

However, in the project, it is recommended that you use the project in strict accordance with the meanings of the remaining three annotations except Componen . This is good for a layered Web architecture!!

This is about the role of these four annotations in Springmvc, in fact srping the role of these four annotations and springmvc the same.

Example:

1. Control layer

@Controller//Comment as Controller
@RequestMapping ("/login")
public class Loginaction {

@Autowired
@Qualifier ("UserService")//Note Specify the injected Bean
Private Iuserservice UserService;

。。。。。。 Other slightly ...

}

2. Business Logic Layer

@Service ("UserService")
public class Userserviceimpl implements Iuserservice {

@Autowired
@Qualifier ("Userdao")
Private Iuserdao Userdao;

。。。。。。 Other slightly ...

}

3. Persistence Layer

@Repository ("Userdao")
public class Userdaoimpl implements Iuserdao {
private static Logger Logger = Loggerfactory.getlogger (Userdaoimpl.class);
Private DataSource DataSource;
private JdbcTemplate template;

@Autowired
Public Userdaoimpl (DataSource DataSource) {
This.datasource= DataSource;
Template = new JdbcTemplate (This.datasource);
}

Spring's four basic annotations annotation (control layer, business layer, persistence layer) @Component, @