spring Bean的三種配置方式

Spring Bean有三種配置方式：

• 傳統的XML配置方式
• 基於注解的配置
• 基於類的Java Config

添加spring的maven repository

<dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <!--這個jar文件包含Spring框架基本的核心工具類，Spring其它組件要都要使用到這個包里的類，是其它組件的基本核心 -->
      <version>4.1.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <!--這個jar文件為Spring核心提供了大量擴展 -->
      <version>4.1.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <!--對JUNIT等測試框架的簡單封裝 -->
      <version>4.1.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <!--為JDBC、Hibernate、JDO、JPA等提供的一致的聲明式和編程式事務管理。-->
      <version>4.1.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <!--這個jar文件是所有應用都要用到的，它包含訪問配置文件、創建和管理bean以及進行（IoC/DI）操作相關的所有類 -->
      <version>4.1.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <!--這個jar文件包含對Spring對JDBC數據訪問進行封裝的所有類。 -->
      <version>4.1.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
    </dependency>

一、傳統的XML配置方式

　　BeanFactory.java

package com.stonegeek.service;

/**
 * Created by StoneGeek on 2018/5/13.
 */
public interface BeanFactory {
    public void Beantest();
}

　　BeanFactoryImpl.java

package com.stonegeek.service.impl;

import com.stonegeek.service.BeanFactory;

/**
 * Created by StoneGeek on 2018/5/13.
 */
public class BeanFactroyImpl implements BeanFactory {
    @Override
    public void Beantest() {
        System.out.println("----------------This is a 傳統的XML配置的bean!-------------------");
    }
}

　　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:context="http://www.springframework.org/schema/context"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd
    ">
    <bean id="beanFactroy" class="com.stonegeek.service.impl.BeanFactroyImpl" />

</beans>

　　TestBean1.java

package com.stonegeek;

import com.stonegeek.service.BeanFactory;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Created by StoneGeek on 2018/5/13.
 */
public class TestBean1 {
    @Test
    public void test(){
        ApplicationContext ctx= new ClassPathXmlApplicationContext("applicationContext.xml");
        BeanFactory beanFactory=(BeanFactory) ctx.getBean("beanFactroy");
        beanFactory.Beantest(); //----------------This is a 傳統的XML配置的bean!-------------------
    }
}

二、基於java注解的配置

　　如果一個類使用了@Service，那么此類將自動注冊成一個bean，不需要再在applicationContext.xml文件定義bean了，類似的還包括@Component、@Repository、@Controller。

　　然后需要在applicationContext.xml文件中加一行，作用是自動掃描base-package包下的注解：

<context:component-scan base-package="com.stonegeek" />

　　BeanFactoryImpl.java

package com.stonegeek.service.impl;

import com.stonegeek.service.BeanFactory;
import org.springframework.stereotype.Service;

/**
 * Created by StoneGeek on 2018/5/13.
 */
@Service("beanFactory")
public class BeanFactroyImpl implements BeanFactory {
    @Override
    public void Beantest() {
        System.out.println("----------------This is a 基於Java注解的bean!-------------------");
    }
}

　　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:context="http://www.springframework.org/schema/context"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd
    ">
    <context:component-scan base-package="com.stonegeek" />


</beans>

　　TestBean2.java

package com.stonegeek;

import com.stonegeek.service.BeanFactory;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Created by StoneGeek on 2018/5/13.
 */
public class TestBean2 {
    @Test
    public void test(){
        ApplicationContext ctx= new ClassPathXmlApplicationContext("applicationContext.xml");
        BeanFactory beanFactory=(BeanFactory) ctx.getBean("beanFactory");
        beanFactory.Beantest();  //This is a 基於java注解的bean！
    }
}

三、基於類的Java Config

　　通過java類定義spring配置元數據，且直接消除xml配置文件

　　Spring3.0基於java的配置直接支持下面的注解：

　　@Configuration

　　@Bean

　　@DependsOn

　　@Primary

　　@Lazy

　　@Import

　　@ImportResource

　　@Value

 

　　BeanFactoryImpl.java

package com.stonegeek.service.impl;

import com.stonegeek.service.BeanFactory;

/**
 * Created by StoneGeek on 2018/5/13.
 */
public class BeanFactoryImpl implements BeanFactory {
    @Override
    public void Beantest() {
        System.out.println("----------------This is a 基於類的Java Config的bean!-------------------");
    }
}

　　BeanConfig.java

package com.stonegeek.service.config;


import com.stonegeek.service.BeanFactory;
import com.stonegeek.service.impl.BeanFactoryImpl;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * Created by StoneGeek on 2018/5/13.
 */
@Configuration
public class BeanConfig {
    @Bean
    public BeanFactory beanFactory(){
        return new BeanFactoryImpl();
    }
}

　　TestBean3.java

package com.stonegeek;

import com.stonegeek.service.BeanFactory;
import com.stonegeek.service.config.BeanConfig;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

/**
 * Created by StoneGeek on 2018/5/13.
 */
public class TestBean3 {
    @Test
    public void test(){
        ApplicationContext applicationContext=new AnnotationConfigApplicationContext(BeanConfig.class);
        BeanFactory beanFactorys=applicationContext.getBean(BeanFactory.class);
        beanFactorys.Beantest();  //This is a 基於類的Java Config Bean！
    }
}

　　以上就是spring bean的三種配置方式的簡單介紹！！