Spring探究-----配置Bean详解

package com.spring.configureBean;

/**
 * 车辆类
 * 
 * @author yyx 2019年6月11日
 */
public class Car {
    /**
     * 车辆名称
     */
    private String carName;
    /**
     * 车辆价格
     */
    private Integer carPrice;
    
    public Car() {
        super();
    }

    public Car(String carName, Integer carPrice) {
        super();
        this.carName = carName;
        this.carPrice = carPrice;
    }
    
    public String getCarName() {
        return carName;
    }

    public void setCarName(String carName) {
        this.carName = carName;
    }

    public Integer getCarPrice() {
        return carPrice;
    }

    public void setCarPrice(Integer carPrice) {
        this.carPrice = carPrice;
    }

    @Override
    public String toString() {
        return "Car [carName=" + carName + ", carPrice=" + carPrice + "]";
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="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">

    <bean id="carAttribute" class="com.spring.configureBean.Car">
        <property name="carName">
            <!-- 若字面值中包含特殊字符, 则可以使用 DCDATA 来进行赋值 -->
            <value><![CDATA[<BMW>]]></value>
        </property>
        <property name="carPrice" value="250000"></property>
    </bean>
</beans>

<!-- 构造器注入值，在 Bean 中必须有对应的构造器 -->
    <bean id="carConstruct" class="com.spring.configureBean.Car">
        <!--根据 index和 value精确的定位，index按属性顺序对应 -->
        <constructor-arg index="0">
            <value><![CDATA[<BMW>]]></value>
        </constructor-arg>
        <constructor-arg value="250000" index="1"></constructor-arg>
    </bean>

package com.spring.configureBean;
/**
 * 静态工厂方法：直接调用某一个类的静态方法就可以返回Bean
 * @author yyx
 * 2019年6月11日
 */

import java.util.HashMap;
import java.util.Map;

public class StaticCarFactory {
    private static Map<String, Car> cars = new HashMap<>();
    static {
        cars.put("Audi", new Car("Audi", 350000));
        cars.put("Ford", new Car("Ford", 200000));
    }

    /**
     * 静态方法
     * 
     * @param keyValue
     * @return
     */
    public static Car getCar(String keyValue) {
        return cars.get(keyValue);
    }
}

<!-- 静态工厂注入配置bean：不推荐 注意：不是配置静态工厂方法实例，而是配置bean实例 -->
<bean id="staticFactoryCar" class="com.spring.configureBean.StaticCarFactory" factory-method="getCar">
       <!-- 如果静态方法需要参数，则用constructor-arg配置参数 -->
       <constructor-arg value="Audi"></constructor-arg>
</bean>

package com.spring.configureBean;

import java.util.HashMap;
import java.util.Map;

/**
 * 实例工厂方法：即需要创建工厂本身，再调用工厂的实例方法来返回Bean的实例
 * 
 * @author yyx 2019年6月16日
 */
public class InstanceCarFactory {
    private Map<String, Car> cars = null;

    public InstanceCarFactory() {
        cars = new HashMap<>();
        cars.put("Audi", new Car("Audi", 350000));
        cars.put("Ford", new Car("Ford", 200000));
    }

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

<!-- 配置工厂实例 -->
    <bean id="carFactory" class="com.spring.configureBean.InstanceCarFactory"></bean>
    
    <bean id="instanceFactoryCar" factory-bean="carFactory"
    factory-method="getCar">
       <constructor-arg value="Ford"></constructor-arg>
    </bean>

package com.spring.configureBean;

import org.springframework.beans.factory.FactoryBean;

public class FactoryBeanCar implements FactoryBean<Car> {
    //可以设置参数
    private String carName;
    
    public void setCarName(String carName) {
        this.carName = carName;
    }

    /**
     * 返回Bean对象
     */
    @Override
    public Car getObject() throws Exception {
        return new Car(carName, 500000);
    }
    
    /**
     * 返回Bean的类型
     */
    @Override
    public Class<?> getObjectType() {
        return Car.class;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }

}

<bean id="factoryBeanCar" class="com.spring.configureBean.FactoryBeanCar">
        <property name="carName" value="BMW"></property>
    </bean>