[ * ] 靜態(tài)工程方法創(chuàng)建bean

[ * ] 實(shí)例工程方法創(chuàng)建bean

[ * ] spring的FactoryBean創(chuàng)建bean

靜態(tài)工程方法創(chuàng)建bean

直接用類的靜態(tài)方法就可以返回bean的實(shí)例

 public class StaticCarFactory {
   private static Map<String, Car> cars = new HashMap<String, Car>();

   static {
       cars.put("audi", new Car("audi", 20000));
       cars.put("ford", new Car("ford", 40000));
   }

   public static Car getCar(String name) {
       return cars.get(name);
   }
}

 <!-- 通過靜態(tài)工程方法配置bean
    注意：不是配置靜態(tài)工程方法實(shí)例，而是配置bean實(shí)例

         class 屬性：指向靜態(tài)工程方法全類名稱
     factory-method： 指向靜態(tài)工程方法
    constructor-arg：如果靜態(tài)工程方法需要傳入?yún)?shù)凤薛，這個(gè)使用constructor-arg: 配置參數(shù)

    -->
<bean id="car1"
          class="com.sunny.beans.factory.StaticCarFactory"
          factory-method="getCar">
        <constructor-arg name="name" value="audi"/>
    </bean>

靜態(tài)工程方法創(chuàng)建bean

先創(chuàng)建工程本身声功，在調(diào)用工程的實(shí)例方法

public class InstanceCarFactory {
    private static Map<String, Car> cars;

    public InstanceCarFactory() {
        cars = new HashMap<String, Car>();

        cars.put("audi", new Car("audi", 20000));
        cars.put("ford", new Car("ford", 40000));
    }

    public Car getCar(String name) {
        return cars.get(name);
    }
}

    <!--通過實(shí)例的工程方法創(chuàng)建bean-->
    <!--配置工程實(shí)例-->
    <bean id="carFactory"
          class="com.sunny.beans.factory.InstanceCarFactory"/>

    <bean id="car2"
          factory-bean="carFactory"
          factory-method="getCar">
        <constructor-arg name="name" value="ford"/>
    </bean>

spring的FactoryBean創(chuàng)建bean

實(shí)現(xiàn)FactoryBean接口

public class CarFactoryBean implements FactoryBean<Car> {
    private String brand;

    public void setBrand(String brand) {
        this.brand = brand;
    }

    /**
     * @return bean對象
     * @throws Exception 異常
     */
    @Override
    public Car getObject() throws Exception {
        return new Car(brand, 40000);
    }

    /**
     * @return bean的類型
     */
    @Override
    public Class<?> getObjectType() {
        return Car.class;
    }

    /**
     * @return 是否單例
     */
    @Override
    public boolean isSingleton() {
        return true;
    }
}

    <bean id="car3"
          class="com.sunny.beans.factory.CarFactoryBean">
       <property name="brand" value="CarFactoryBean"/>
    </bean>