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Spring之InitializingBean接口和DisposableBean接口的使用

更新時(shí)間：2024年01月13日 10:36:23 作者：波波烤鴨

這篇文章主要介紹了Spring之InitializingBean接口和DisposableBean接口的使用方式,具有很好的參考價(jià)值,希望對(duì)大家有所幫助,如有錯(cuò)誤或未考慮完全的地方,望不吝賜教

1.InitializingBean

該接口的作用是：

允許一個(gè)bean在它的所有必須屬性被BeanFactory設(shè)置后，來執(zhí)行初始化的工作，該接口中只有一個(gè)方法，afterPropertiesSet

public interface InitializingBean {

	/**
	 * Invoked by the containing {@code BeanFactory} after it has set all bean properties
	 * and satisfied {@link BeanFactoryAware}, {@code ApplicationContextAware} etc.
	 * <p>This method allows the bean instance to perform validation of its overall
	 * configuration and final initialization when all bean properties have been set.
	 * @throws Exception in the event of misconfiguration (such as failure to set an
	 * essential property) or if initialization fails for any other reason
	 */
	void afterPropertiesSet() throws Exception;

}

2.DisposableBean

該接口的作用是：允許在容器銷毀該bean的時(shí)候獲得一次回調(diào)。

DisposableBean接口也只規(guī)定了一個(gè)方法：destroy

public interface DisposableBean {

	/**
	 * Invoked by the containing {@code BeanFactory} on destruction of a bean.
	 * @throws Exception in case of shutdown errors. Exceptions will get logged
	 * but not rethrown to allow other beans to release their resources as well.
	 */
	void destroy() throws Exception;

}

3.案例演示

/**
 * 實(shí)現(xiàn)InitializingBean和DisposableBean接口
 * @author dengp
 *
 */
public class User implements InitializingBean,DisposableBean{

	private int id;
	
	private String name;
	
	private String beanName;
	
	public User(){
		System.out.println("User 被實(shí)例化");
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		System.out.println("設(shè)置："+name);
		this.name = name;
	}

	public String getBeanName() {
		return beanName;
	}

	public void setBeanName(String beanName) {
		this.beanName = beanName;
	}
	
	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + ", beanName=" + beanName + "]";
	}

	@Override
	public void destroy() throws Exception {
		// TODO Auto-generated method stub
		System.out.println("destory ....");
	}

	@Override
	public void afterPropertiesSet() throws Exception {
		System.out.println("afterPropertiesSet....");
	}
}

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.xsd">

	<bean class="com.dpb.pojo.User" id="user" >
		<property name="name" value="波波烤鴨"></property>
	</bean>
	
</beans>

測(cè)試代碼

@Test
public void test1() {
	ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
	User user = ac.getBean(User.class);
	System.out.println(user);
	ac.registerShutdownHook();
}

輸出結(jié)果：

User 被實(shí)例化
設(shè)置：波波烤鴨
afterPropertiesSet....
User [id=0, name=波波烤鴨, beanName=null]
destory ....

通過輸出能夠顯示spring初始化bean的時(shí)候，如果bean實(shí)現(xiàn)了InitializingBean接口，會(huì)自動(dòng)調(diào)用afterPropertiesSet方法，在bean被銷毀的時(shí)候如果實(shí)現(xiàn)了DisposableBean接口會(huì)自動(dòng)回調(diào)destroy方法后然后再銷毀