Spring学习十一----------Bean的配置之基于Java的容器注解@Bean

Z时代
2024-01-10
分类：综合

本文内容纲要：Spring学习十一----------Bean的配置之基于Java的容器注解@Bean

@Bean

-@Bean标识一个用于配置和初始化一个由SpringIOC容器管理的新对象的方法，类似于XML配置文件的

-可以在Spring的@Component注解的类中使用@Bean注解任何方法（仅仅是可以）

-在上一点中，通过使用的是@Configuration

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/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>org.springbean</groupId>
	<artifactId>Spring-JavaBean</artifactId>
	<packaging>war</packaging>
	<version>0.0.1-SNAPSHOT</version>
	<name>Spring-JavaBean Maven Webapp</name>
	<url>http://maven.apache.org</url>
	<properties>
		<spring.version>4.3.8.RELEASE</spring.version>
	</properties>
	<dependencies>
		<!-- junit依赖 -->
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>
		<!-- spring核心依赖 -->
		<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>
	</dependencies>
	<build>
		<finalName>Spring-JavaBean</finalName>
	</build>
</project>

3.spring-javabean.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:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">
	<context:component-scan base-package="org.spring.javabean"/>
</beans>

4.Store.java

package org.spring.javabean;
public interface Store {
}

5.StringStore.java

package org.spring.javabean;
public class StringStore implements Store {
	public void init() {
		System.out.println("执行了init方法");
	}
	public void destroy() {
		System.out.println("执行了destroy方法");
	}
}

6.StoreConfig.java

package org.spring.javabean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class StoreConfig {
	@Bean(name="stringStore", initMethod="init", destroyMethod="destroy")
	public Store stringStore() {
		return new StringStore();
	}
}

7.TestBase.java

package org.spring.javabean.test;
import org.junit.After;
import org.junit.Before;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.util.StringUtils;
public class TestBase {
	private ClassPathXmlApplicationContext context;
	private String springXmlPath;
	/**
	 * 无参构造器
	 */
	public TestBase() {
	}
	/**
	 * 含参构造器，初始化spring配置文件路径
	 * 
	 * @param springXmlPath
	 * 						spring配置文件路径
	 */
	public TestBase(String springXmlPath) {
		this.springXmlPath = springXmlPath;
	}
	/**
	 * 初始化加载spring配置文件到IOC容器中
	 */
	@Before
	public void before() {
		if(StringUtils.isEmpty(springXmlPath)){
			springXmlPath = "classpath:spring-*.xml";
		}
		context = new ClassPathXmlApplicationContext(springXmlPath.split("[,\\s]+"));
		context.start();
	}
	/**
	 * 销毁IOC容器
	 */
	@After
	public void after() {
		if(context != null){
			context.destroy();
		}
	}
	/**
	 * 通过bean ID获取bean对象
	 * 
	 * @param beanId
	 * 				bean ID
	 * @return
	 */
	public Object getBean(String beanId) {
		return context.getBean(beanId);
	}
}

8.TestSpringJavaBean.java

package org.spring.javabean.test;
import org.junit.Test;
import org.spring.javabean.Store;
public class TestSpringJavaBean extends TestBase {
	public TestSpringJavaBean() {
		super("classpath:spring-javabean.xml");
	}
	@Test
	public void testJavaBean() {
		Store store = (Store) super.getBean("stringStore");
		System.out.println(store.getClass().getName());
	}
}