SpringIOC创建对象的方式案例

一、配置文件spring-ioc.xml相关代码

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

    <!--1、无参构造-->
    <bean id="userEntity1" class="com.zhq.pojo.UserEntity"/>

    <!--2、有参构造-->
    <bean id="userEntity2" class="com.zhq.pojo.UserEntity">
        <constructor-arg name="name" value="猪大宝"></constructor-arg>
        <constructor-arg name="age" value="18"></constructor-arg>
    </bean>

    <!--3、实例工厂-->
    <bean id="objectFactory" class="com.zhq.pojo.ObjectFactory"/>
    <bean id="userEntity3" factory-bean="objectFactory" factory-method="getUserEntity"/>

    <!--4、静态工厂-->
    <bean id="userEntity4" class="com.zhq.pojo.ObjectFactory" factory-method="getStaticUserEntity"/>

</beans>

二、相关实体类 

public class UserEntity {
    private String name;
    private Integer age;

    public UserEntity() {
        System.out.println("无参构造函数");
    }

    public UserEntity(String name, Integer age) {
        System.out.println("有参构造函数 name:" + name + "----" + age);
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "UserEntity [name=" + name + ", age=" + age + "]";
    }
}

public class ObjectFactory {
    /**
     *
     * @methodDesc: 功能描述:(实例工厂方法)
     */
    public UserEntity getUserEntity() {

        System.out.println("ObjectFactory getUserEntity");
        return new UserEntity("zhangsan", 19);
    }

    /**
     *
     * @methodDesc: 功能描述:(静态工厂方法)
     */
    static public UserEntity getStaticUserEntity() {
        System.out.println("ObjectFactory getStaticUserEntity");
        return new UserEntity("static  zhangsan", 19);
    }
}

三、测试方法 

public class SpringIOC {
    public static void main(String[] args) {
        //加载spring容器
        ClassPathXmlApplicationContext applicationContext=new ClassPathXmlApplicationContext("spring-ioc.xml");

        //1、无参构造
        UserEntity userEntity1 = (UserEntity) applicationContext.getBean("userEntity1");
        System.out.println(userEntity1);

        //2、有参构造
        UserEntity userEntity2 = (UserEntity) applicationContext.getBean("userEntity2");
        System.out.println(userEntity2);

        //3、实例工厂
        UserEntity userEntity3 = (UserEntity) applicationContext.getBean("userEntity3");
        System.out.println(userEntity3);

        //3、静态工厂
        UserEntity userEntity4 = (UserEntity) applicationContext.getBean("userEntity4");
        System.out.println(userEntity4);
    }
}