[Liu Yang java]_spring Related configuration Introduction _ 5th Lecture

In this section we introduce the relevant common configuration of the spring framework

• Spring relies on injection in two ways (construct method injection and setter mode injection)
• P-namespace Mode configuration
• Properties Property File Configuration method
• How collection objects are configured
• Bean Scopes scope (singleton scope and native scope)

1. Spring Dependency Injection method

• Constructs method injection, which is equivalent to invoking a constructor method to inject a dependency between its objects into the object when spring initializes the object
  • First define the dependent objects in the class.
  • Then define the constructor method by setting the object's dependencies in the constructor's parameters
  • Finally, use the <constructor-arg> tag in the spring configuration file to get the dependency injection of the object.

 package   com.gxa.spring.day02;  public  class   Petserviceimpl { private  petdaoimpl Petdao ; //         dependent object  public  Petserviceimpl (Petdaoimpl Petdao) {//  Di of the construction method     this . Petdao = Petdao;  public  void   Selectpet () {Petdao.selectpet (); }}

 Package com.gxa.spring.day02;  Public class Petdaoimpl {        publicvoid  Selectpet () {        /**         * Complete Pet data Query          *        /System.out.println ("= = Pet Data Query = =");}    }

<?XML version= "1.0" encoding= "UTF-8"?><Beansxmlns= "Http://www.springframework.org/schema/beans"Xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"xmlns:p= "http://www.springframework.org/schema/p"xsi:schemalocation= "Http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd" >        <BeanID= "Petservice"class= "Com.gxa.spring.day02.PetServiceImpl">        <Constructor-argname= "Petdao"ref= "Petdao"></Constructor-arg>    </Bean>        <BeanID= "Petdao"class= "Com.gxa.spring.day02.PetDaoImpl"></Bean>    </Beans>

• Value injection, which completes the object's di by adding a setter method to the dependent object
  • Define the dependent objects first.
  • Adding setter methods to dependent objects
  • Finally, using the <property.../> tag in the config file is ok.

 Packagecom.gxa.spring.day01; Public classPetserviceimpl {PrivatePetdaoimpl Petdao;//Dependent Objects    PrivateItemdaoimpl Itemdao;//Dependent Objects         Public voidSetpetdao (Petdaoimpl Petdao) { This. Petdao =Petdao; }         Public voidSetitemdao (Itemdaoimpl Itemdao) { This. Itemdao =Itemdao; }         Public voidSelectpet () {Petdao.selectpet ();    Itemdao.selectitem (); }}

 package   com.gxa.spring.day01;  public  class   Petdaoimpl { public  void   Selectpet () { /**   * Complete Pet data query  */  System.out.println (" = = Pet Data Query = = "

 Package com.gxa.spring.day01;  Public class Itemdaoimpl {        publicvoid  SelectItem () {        /**         * Complete the PET classification data         Query *        /System.out.println ("= = Pet Classification data Query = =");}    }

<?XML version= "1.0" encoding= "UTF-8"?><Beansxmlns= "Http://www.springframework.org/schema/beans"Xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"xsi:schemalocation= "Http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd" >        <BeanID= "Person"class= "Com.gxa.spring.day01.Person"></Bean>        <BeanID= "Petservice"class= "Com.gxa.spring.day01.PetServiceImpl">        < Propertyname= "Petdao"ref= "Petdao"></ Property>        < Propertyname= "Itemdao"ref= "Itemdao"></ Property>    </Bean>        <BeanID= "Petdao"class= "Com.gxa.spring.day01.PetDaoImpl"></Bean>        <BeanID= "Itemdao"class= "Com.gxa.spring.day01.ItemDaoImpl"></Bean></Beans>

[Liu Yang java]_spring Related configuration Introduction _ 5th]