Springmvc3.0 comments

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Springmvc3.0 comments

1, why use annotations, what are the benefits of annotations?

SPRINGMVC3.0 is programming based on annotations, which can greatly improve development efficiency and maintenance costs. Compared to SSH (struts2+spring+hibernate) springmvc3.0, struts2.0, Spring, hinernate configuration files are written and maintained, allowing for faster development. All of this is done by programming based on annotations.

2, how to understand the annotations?

Annotations can be written on the class, or can be written on the method above, in our system, the method-based annotation is mainly used in the Controller, class-based annotations are mainly in the Controller class, Business logic Layer (SERVICEIMPL), the data layer (DAOIMPL) implementation class.

Class-based annotations, such as controller, are equivalent to invoking a singleton object in the system.

The controller of spring is singleton. This means that it will be shared by multiple request threads.

3, what are the commonly used annotations?

• @Controller

• @Service

• @Autowired

• @RequestMapping

• @RequestParam

• @ModelAttribute

• @Cacheable

• @CacheFlush

• @Resource

• @PostConstruct

• @PreDestroy

• @Repository

• @Component (not recommended)

• @Scope

• @SessionAttributes

• @InitBinder

• @Required

• @Qualifier

What are the annotations that need to be understood in our system? Here's a look at the classification, to explain:

In the controller:

Class-based annotations, @Controller

• For example

@Controller
public class Softcreatecontroller extends Simplebasecontroller {}

• OR
@Controller ("Softcreatecontroller")

• description

@Controller is responsible for registering a bean into the spring context, the bean ID defaults to the class name beginning with the lowercase letter

@Resource

• For example

@Resource
Private DataSource DataSource; Inject the bean named ' DataSource '

• OR

@Resource (name= "DataSource")
@Resource (Type=datasource.class)

• description

@Resource is found by default by the Bean's name, and if no find is performed by type without explicitly specifying the Name property for @Resource annotations, if it is labeled in the Beanfactory type, the ApplicationContext class Type, resourceloader types, applicationeventpublisher types, and Messagesource types, Spring automatically injects instances of these implementation classes without the need for additional action. The Name property does not need to be specified (or specified as "") at this time, otherwise the injection fails;

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@Service annotations based on the business logic layer

• For example

@Service
public class Softcreateserviceimpl implements Isoftcreateservice {}

• OR
@Service ("Toursearchdataservice")

Public class Toursearchdataserviceimpl implements toursearchdataservice{}

• description

@Service is responsible for registering a bean into the spring context, the bean ID defaults to the class name beginning with the lowercase letter

@Repository annotations based on the data layer

• Similar to @controller, @Service, the Bean is registered with the spring context and is not described.

@Repository ("Toursearchdatadao")

Public class Toursearchdatadaoimpl extends searchhibernatedaosupport implements Toursearchdatadao {}

Related keywords: android tutorial

Springmvc3.0 comments