Spring学习五----------Bean的配置之Bean的生命周期

2022-11-01 07:57:33

Bean的生命周期

1.定义

2.初始化

3.使用

4.销毁

初始化和销毁的三种方式

1.实现org.springframework.beans.factory.InitializingBean和org.springframework.beans.factory.DisposableBean接口

2.配置init-method和destroy-method

3.配置全局默认初始化和销毁方法default-init-method和default-destroy-method

实例

1.项目结构

2.pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

	<modelVersion>4.0.0</modelVersion>

	<groupId>org.spring</groupId>

	<artifactId>Spring</artifactId>

	<version>0.0.1-SNAPSHOT</version>

	<packaging>jar</packaging>

	<name>Spring</name>

	<url>http://maven.apache.org</url>

	<properties>

		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

		<spring.version>4.3.7.RELEASE</spring.version>

	</properties>

	<dependencies>

		<!-- junit依赖 -->

		<dependency>

			<groupId>junit</groupId>

			<artifactId>junit</artifactId>

			<version>4.12</version>

			<scope>test</scope>

		</dependency>

		<!-- spring依赖 -->

		<dependency>

		    <groupId>org.springframework</groupId>

		    <artifactId>spring-core</artifactId>

		    <version>${spring.version}</version>

		</dependency>

		<dependency>

		    <groupId>org.springframework</groupId>

		    <artifactId>spring-beans</artifactId>

		    <version>${spring.version}</version>

		</dependency>

		<dependency>

		    <groupId>org.springframework</groupId>

		    <artifactId>spring-context</artifactId>

		    <version>${spring.version}</version>

		</dependency>

		<dependency>

		    <groupId>org.springframework</groupId>

		    <artifactId>spring-web</artifactId>

		    <version>${spring.version}</version>

		</dependency>

		<dependency>

		    <groupId>org.springframework</groupId>

		    <artifactId>spring-webmvc</artifactId>

		    <version>${spring.version}</version>

		</dependency>

	</dependencies>

</project>

3.spring-beanlifecycle.xml（三选一）

　　3.1 实现org.springframework.beans.factory.InitializingBean和org.springframework.beans.factory.DisposableBean接口

<?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="beanLifeCycle" class="org.spring.bean.BeanLifeCycle"/>        

</beans>

　　3.2 配置init-method和destroy-method

<?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="beanLifeCycle" class="org.spring.bean.BeanLifeCycle"

		init-method="start" destroy-method="stop"/>        

</beans>

　　3.3 配置全局默认初始化和销毁方法default-init-method和default-destroy-method

<?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"

        default-init-method="defaultInit" default-destroy-method="defaultDestroy">

	<bean id="beanLifeCycle" class="org.spring.bean.BeanLifeCycle"/>        

</beans>

4.BeanLifeCycle.java（三选一）

　　4.1 实现org.springframework.beans.factory.InitializingBean和org.springframework.beans.factory.DisposableBean接口

package org.spring.bean;

import org.springframework.beans.factory.DisposableBean;

import org.springframework.beans.factory.InitializingBean;

public class BeanLifeCycle implements InitializingBean, DisposableBean {

	/**

	 * 初始化

	 */

	public void afterPropertiesSet() throws Exception {

		System.out.println("Bean Init.");

	}

	/**

	 * 销毁

	 */

	public void destroy() throws Exception {

		System.out.println("Bean Destroy.");

	}

}

　　4.2 配置init-method和destroy-method

package org.spring.bean;

public class BeanLifeCycle {

	/**

	 * 初始化

	 */

	public void start() throws Exception {

		System.out.println("Bean Start.");

	}

	/**

	 * 销毁

	 */

	public void stop() throws Exception {

		System.out.println("Bean Stop.");

	}

}

　　4.3 配置全局默认初始化和销毁方法default-init-method和default-destroy-method

package org.spring.bean;

public class BeanLifeCycle {

	/**

	 * 初始化

	 */

	public void defaultInit() throws Exception {

		System.out.println("Bean DefaultInit.");

	}

	/**

	 * 销毁

	 */

	public void defaultDestroy() throws Exception {

		System.out.println("Bean DefaultDestroy.");

	}

}

5.UnitTestBase

package org.spring.ioc.test;

import org.junit.After;

import org.junit.Before;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import org.springframework.util.StringUtils;

/**

 * 单元测试初始化类

 *

 */

public class UnitTestBase {

	private ClassPathXmlApplicationContext context;

	private String springXmlPath;

	/**

	 * 无参构造器

	 */

	public UnitTestBase() {

	}

	/**

	 * 含参构造器

	 *

	 * @param springXmlPath

	 * 						spring配置文件路径

	 */

	public UnitTestBase(String springXmlPath) {

		this.springXmlPath = springXmlPath;

	}

	/**

	 * 初始化spring配置文件

	 */

	@Before//在@Test注解的方法执行前执行

	public void before() {

		if(StringUtils.isEmpty(springXmlPath)) {//默认spring配置文件路径

			springXmlPath = "classpath*:spring-*.xml";

		}

		//加载配置文件，一个context表示一个容器

		context = new ClassPathXmlApplicationContext(springXmlPath.split("[,\\s]+"));

		//启动组件

		context.start();

	}

	/**

	 * 销毁spring组件

	 */

	@After//在@Test注解的方法执行后执行

	public void after() {

		context.destroy();//销毁组件

	}

	/**

	 * 获取spring中定义的bean实例

	 *

	 * @param beanId

	 *

	 * @return

	 */

	@SuppressWarnings("unchecked")

	protected <T extends Object> T getBean(String beanId) {

		return (T) context.getBean(beanId);

	}

	/**

	 * 获取spring中定义的bean实例

	 *

	 * @param clazz

	 *

	 * @return

	 */

	protected <T extends Object> T getBean(Class<T> clazz) {

		return (T) context.getBean(clazz);

	}

}

6.TestBeanLifeCycle

package org.spring.ioc.test;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.junit.runners.BlockJUnit4ClassRunner;

import org.spring.bean.BeanLifeCycle;

@RunWith(BlockJUnit4ClassRunner.class)//指定JUnit默认执行类

public class TestBeanLifeCycle extends UnitTestBase {

	public TestBeanLifeCycle() {//通过构造方法传入spring配置文件路径

		super("classpath*:spring-beanlifecycle.xml");

	}

	@Test

	public void testScope() {

		BeanLifeCycle bean = super.getBean("beanLifeCycle");

	}

}

7.效果预览

　　7.1 实现org.springframework.beans.factory.InitializingBean和org.springframework.beans.factory.DisposableBean接口

　　7.2 配置init-method和destroy-method

　　7.3 配置全局默认初始化和销毁方法default-init-method和default-destroy-method

　　7.4 三种方式一起执行

8.总结

　　1）实现接口方式的初始化和销毁先于配置init-method和destroy-method

　　2）当实现接口方式的初始化和销毁或配置init-method和destroy-method 时，配置全局默认初始化和销毁方法default-init-method和default-destroy-method不生效

参考：http://www.imooc.com/video/3751

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