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!!

Example:

1. Control layer

    // Note for controller @RequestMapping ("/login")  Publicclass  loginaction {@Autowired @Qualifier ("userservice"// Note specifying the injected Bean Private　　Iuserservice UserService; 。。。。。。　　Other slightly ... }　　

2. Business Logic Layer

   @Service ("userservice")  publicclass  Userserviceimpl Implements Iuserservice {@Autowired @Qualifier ("userdao") 　　Private  Iuserdao Userdao; 。。。。。。　　Other slightly ... }

3. Persistence Layer

@Repository ("Userdao") Public classUserdaoimpl implements Iuserdao {Private StaticLogger Logger = Loggerfactory.getlogger (Userdaoimpl.class); PrivateDataSource DataSource; Privatejdbctemplate template; @Autowired PublicUserdaoimpl (DataSource DataSource) { This. datasource=DataSource; Template=NewJdbcTemplate ( This. DataSource); }

Four basic annotations in SPRINGMVC