Spring annotations (Spring Annotations)

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Package

Annotation	Detail/import Statement
@Service	Import Org.springframework.stereotype.Service;
@Repository	Import Org.springframework.stereotype.Repository;
@Component	Import org.springframework.stereotype.Component;
@Autowired	Import org.springframework.beans.factory.annotation.Autowired;
@Transactional	Import org.springframework.transaction.annotation.Transactional;
@Scope	Import Org.springframework.context.annotation.Scope;
Spring MVC Annotations
@Controller	Import Org.springframework.stereotype.Controller;
@RequestMapping	Import org.springframework.web.bind.annotation.RequestMapping;
@PathVariable	Import org.springframework.web.bind.annotation.PathVariable;
@RequestParam	Import Org.springframework.web.bind.annotation.RequestParam;
@ModelAttribute	Import Org.springframework.web.bind.annotation.ModelAttribute;
@SessionAttributes	Import org.springframework.web.bind.annotation.SessionAttributes;
Spring Security Annotations
@PreAuthorize	Import org.springframework.security.access.prepost.PreAuthorize;

@Service, @Repository, @Controller, @Component

@Service, @Repository, @Controller, @Component these four are all beans used to annotate spring, and they are equivalent at the point of view of the program. But from the name, it is easy to see that @service is the bean–service of the annotation business layer, @Repository is the Bean–dao of the annotations persistence layer, @Controller is the controller of the annotated MVC, @Component Used to annotate ordinary beans, when the bean is poorly categorized, use @component.

@Autowired

Automatic injection of the value, as follows automatic injection of Companydao. The premise is to ensure that Companydao exists in the spring context.

@Servicepublic class Companyserviceimpl implements Companyservice {@Autowired

Private Companydao Companydao;

...

}

@Transactional

Add @transactional to a service class, stating that all methods of the service support transaction management, and if you add @transactional on a method, only declare that the method supports transactions. A transaction is opened before the method that supports the transaction begins execution, and is rolled back when an exception is encountered. Spring's default configuration is that transaction rollback occurs when RuntimeException is encountered.

@Scope

corresponding to the scope of <bean scope= "prototype"/>, its values are singleton, prototype, Request,session,global session and Custom mode.

@RequestMapping

Use this annotation on a class or method to set the URL access address. It has two properties, value specifies the access path, method specifies the request method, and the request method is defined in the Requestmethod class, all in constant form, which uses the GET request by default. It can also specify only the access path, as shown below

The following {Context.path}/comany/addcompany map to the Addcompany method.

@Controller

@RequestMapping ( "/company" ) public class CompanyController {    @Autowired    private CompanyService companyService;   @RequestMapping ( "/addCompany" )Public Modelandview Addcompany (Company C) { ....  } }

@PathVariable

Gets the URL access path variable. In the following example, the access path is the value obtained by the/company/techferry,companyname is Techferry.

@Controller @RequestMapping ( "/company" ) public class CompanyController {    @Autowired    private CompanyService companyService;    @RequestMapping ( "{companyName}" )    public String getCompany(Map<String, Object> map,  @PathVariable String companyName) {      Company company = companyService.findByName(companyName);      map.put( "company" , company);      return "company" ;    }   ... }

@RequestParam

The parameter on the URL is bound to the parameter on the Controller method, and the value of Pagenum is derived from Request.getparameter ("Pagenum").

@[email protected] ("/company") public class Companycontroller {@Autowired

Private Companyservice Companyservice;

@RequestMapping ("/companylist")

Public String listcompanies (map<string, object> Map, @RequestParam int pagenum) {

Map.put ("Pagenum", pagenum);

Map.put ("Companylist", Companyservice.listcompanies (Pagenum));

return "Companylist";

}

...

}

@ModelAttribute

When there are many parameters, the code of the method is very long and very ugly, as defined directly on the method. It is common practice to define a formbean and then use @modelattribute annotations before Formbean. Spring MVC automatically sets the parameters of the URL to the Formbean based on the matching field name.

@Controller

@RequestMapping ( "/company" ) public class CompanyController {    @Autowired    private CompanyService companyService;    @RequestMapping ( "/add" )    public String saveNewCompany( @ModelAttribute Company company) {      companyService.add(company);      return "redirect:" + company.getName();    } ... }

@SessionAttributes

Declare a variable that is stored in the session and can be shared between multiple requests.

@PreAuthorize

Permission validation

In the following example, only the user's ROLE contains "role_admin" to delete the contact.

@Transactional

@PreAuthorize ( "hasRole(‘ROLE_ADMIN‘)" ) public void removeContact(Integer id) {    contactDAO.removeContact(id); }

Spring annotations (Spring Annotations)