【Spring】初始化Spring IoC容器（非Web应用），并获取Bean

参考文章

Introduction to the Spring IoC container and beans

BeanFactory 和ApplicationContext（Bean工厂和应用上下文）

Spring ApplicationContext - Resource leak: 'context' is never closed

版本说明

• JDK 1.7
• Spring3.2.14

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>3.2.14.RELEASE</version>
</dependency>

Java项目中，启动Spring IoC、获取Bean

CLASS PATH下放一个最简单的Spring配置文件

<?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-3.0.xsd">

    <bean id="demoBean" class="com.nicchagil.springapplication.No001initSpringIocAndGetABean.bean.DemoBean">
    </bean>

</beans>

需要由Spring托管的Bean Class

package com.nicchagil.springapplication.No001initSpringIocAndGetABean.bean;

public class DemoBean {
    
    public String test() {
        return "hello spring...";
    }

}

调用类

package com.nicchagil.springapplication.No001initSpringIocAndGetABean;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.nicchagil.springapplication.No001initSpringIocAndGetABean.bean.DemoBean;

public class Call {

    public static void main(String[] args) {
        ApplicationContext context =
                new ClassPathXmlApplicationContext("spring.xml");
        DemoBean d1 = context.getBean("demoBean", DemoBean.class);
        DemoBean d2 = context.getBean("demoBean", DemoBean.class);
        
        /* execu the method*/
        System.out.println(d1.test());
        System.out.println(d2.test());
        
        /* default singleton */
        System.out.println("demoBean isSingleton ? -> " + context.isSingleton("demoBean"));
        System.out.println(d1);
        System.out.println(d2);
        System.out.println("d1 == d2 -> " + (d1 == d2));
    }

}

日志

hello spring...
hello spring...
demoBean isSingleton ? -> true
com.nicchagil.springapplication.No001initSpringIocAndGetABean.bean.DemoBean@4857b188
com.nicchagil.springapplication.No001initSpringIocAndGetABean.bean.DemoBean@4857b188
d1 == d2 -> true