Spring Introductory Lesson 12th

How to configure a bean

Through the factory method (static factory method & Instance Factory method), Factorybean

To create a bean by calling the static factory method

Calling the static factory method to create the bean is the process of encapsulating the object creation into a static method, and when the client needs the object, simply call the static method without worrying about the details of the object being created.

To declare a bean created through a static method, you need to specify the method class owning the factory in the Bean's class attribute, specifying the name of the factory method in the Factory-method attribute, and finally, using the <constructor-arg> element to pass method parameters for the method.

Look at the code

 Packagelogan.spring.study.factory; Public classCar {PrivateString brand; Private intPrice ;  PublicString Getbrand () {returnbrand; }     Public voidSetbrand (String brand) { This. Brand =brand; }     Public intGetPrice () {returnPrice ; }     Public voidSetprice (intPrice ) {         This. Price =Price ; } @Override PublicString toString () {return"Car [brand=" + Brand + ", price=" + Price + "]"; }     PublicCar (String brand,intPrice ) {        Super();  This. Brand =brand;  This. Price =Price ; }}

 Packagelogan.spring.study.factory;ImportJava.util.HashMap;ImportJava.util.Map; Public classStaticcarfactory {Private StaticMap<string, car> cars =NewHashmap<string, car>(); Static{cars.put ("Audi",NewCar ("Audi", 3000000)); Cars.put ("Ford",NewCar ("Ford", 4000000)); }         Public StaticCar Getcar (String name) {returncars.get (name); }}

<?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" >    <!--Configure the Bean with a static factory method, note that instead of configuring a static factory method instance, configure the Bean instance -    <BeanID= "Car1"class= "Logan.spring.study.factory.StaticCarFactory"Factory-method= "Getcar">    <Constructor-argvalue= "Audi"></Constructor-arg>    </Bean></Beans>

 Packagelogan.spring.study.factory;ImportOrg.springframework.context.ApplicationContext;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext; Public classMain { Public Static voidMain (string[] args) {//TODO auto-generated Method StubApplicationContext CTX=NewClasspathxmlapplicationcontext ("Beans-factory.xml"); Car car1= (Car) ctx.getbean ("Car1");    System.out.println (CAR1); }}

The following is the output result:

May 21, 2017 11:21:42 am org.springframework.context.support.ClassPathXmlApplicationContext Preparerefresh Info: refreshing org[email protected]7aec35a:startup Date [Sun May 11:21:42 CST 2017]; Root of the context hierarchy May 21, 2017 11:21:42 am Org.springframework.beans.factory.xml.XmlBeanDefinitionReader Loadbeandefinitions info: Loading XML Bean Definitions from class path resource [Beans-factory.xml]car [Brand=audi], price=30 00000]

See the example factory method below:

The instance factory method is the method of the instance factory,

 Packagelogan.spring.study.factory;ImportJava.util.HashMap;ImportJava.util.Map; Public classInstancecarfactory {PrivateMap<string, car> cars =NULL;  Publicinstancecarfactory () {Cars=NewHashmap<string,car>(); Cars.put ("Audi",NewCar ("Audi", 300000)); Cars.put ("Ford",NewCar ("Ford", 500000)); }         PublicCar Getcar (String brand) {returnCars.get (brand); }}

Here is the configuration file:

<?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" >    <!--Configure the Bean with a static factory method, note that instead of configuring a static factory method instance, configure the Bean instance -    <BeanID= "Car1"class= "Logan.spring.study.factory.StaticCarFactory"Factory-method= "Getcar">    <Constructor-argvalue= "Audi"></Constructor-arg>    </Bean>    <!--Configure an instance of the factory -    <BeanID= "Carfactory"class= "Logan.spring.study.factory.InstanceCarFactory"></Bean>    <!--to configure a bean through an instance factory method -    <BeanID= "Car2"Factory-bean= "Carfactory"Factory-method= "Getcar">        <Constructor-argvalue= "Ford"></Constructor-arg>    </Bean></Beans>

 Packagelogan.spring.study.factory;ImportOrg.springframework.context.ApplicationContext;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext; Public classMain { Public Static voidMain (string[] args) {//TODO auto-generated Method StubApplicationContext CTX=NewClasspathxmlapplicationcontext ("Beans-factory.xml"); Car car1= (Car) ctx.getbean ("Car1");                System.out.println (CAR1); Car car2= (Car) ctx.getbean ("Car2");    System.out.println (CAR2); }}

Here are the output results

May 7:27:1819:27:18 CST, 7:27:18Class path resource [beans-
   
    factory.xml]car [Brand=audi, price=3000000
    ]car [Brand=ford, price=500000]
   

Spring Introductory Lesson 12th