Spring文档苦读【2】【在容器外在定义用户对象进容器】

前言

有时我们需要自定义对象，不用Spring来管理我们的对象创建，以便我们在创建过程中做一些其他操作。

一般Spring创建我们对象有两种，一种是使用XML，如下

<?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">

    <bean id="accountDao"
        class="org.springframework.samples.jpetstore.dao.jpa.JpaAccountDao">
        <!-- additional collaborators and configuration for this bean go here -->
    </bean>

    <bean id="itemDao" class="org.springframework.samples.jpetstore.dao.jpa.JpaItemDao">
        <!-- additional collaborators and configuration for this bean go here -->
    </bean>

    <!-- more bean definitions for data access objects go here -->

</beans>

一种是通过，注解的方式。如：@Service，@Component,@Repository等

下面我们就讲解一下如何让用户自定义的创建Bean,并注册到我们的Spring容器中。

用户Bean对象

public class UserBean {
    private String name="My User Bean";

    public String getName() {
        return name;
    }

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

对象装配并获取测试

@RunWith(SpringRunner.class)
@ContextConfiguration("/applicationContext.xml")
public class UserBeanTest {
    @Autowired
    private ConfigurableApplicationContext applicationContext;
    @Before
    public void registerUserBeanTest() {
        DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory)applicationContext.getBeanFactory();
        RootBeanDefinition beanDefinition = new RootBeanDefinition(UserBean.class);
        beanDefinition.setSource(new UserBean());
        /**
         * ConfigurableBeanFactory.SCOPE_SINGLETON(默认)
         * 单例模式，每次获取同一个对象
         * ConfigurableBeanFactory.SCOPE_PROTOTYPE
         * 这个是说在每次注入的时候回自动创建一个新的bea
         */
        beanDefinition.setScope(ConfigurableBeanFactory.SCOPE_SINGLETON);//
        beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);//表示该类为基础设施类，防止该bean被代理
        beanDefinition.getPropertyValues().add("name", "your user bean");
        beanFactory.registerBeanDefinition("userBean", beanDefinition);
    }
    
    @Test
    public void getUserBeanTest() {
        UserBean user = applicationContext.getBean(UserBean.class);
        UserBean user1 = applicationContext.getBean(UserBean.class);
        Assert.assertEquals(user.getName(), "your user bean");
        System.out.println(user.getName());
        System.out.println(user == user1);
    }
}

applicationContext.xml

<?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:oxm="http://www.springframework.org/schema/oxm"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:task="http://www.springframework.org/schema/task"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans.xsd 
    http://www.springframework.org/schema/oxm 
    http://www.springframework.org/schema/oxm/spring-oxm.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/mvc
    http://www.springframework.org/schema/mvc/spring-mvc.xsd
    http://www.springframework.org/schema/task
    http://www.springframework.org/schema/task/spring-task-4.3.xsd
    http://www.springframework.org/schema/aop
    http://www.springframework.org/schema/aop/spring-aop.xsd">
    <context:component-scan base-package="com.may.web,com.may.aspect">
    </context:component-scan>
    <aop:aspectj-autoproxy>
    </aop:aspectj-autoproxy>
    <mvc:annotation-driven />
</beans>