Spring BeanFactory 容器

逍遥壮士

发布于 2020-09-18 11:34:53

3440

发布于 2020-09-18 11:34:53

Spring BeanFactory 容器是什么？

BeanFactory简称bean工厂，是整个spring的核心父类，也是IOC容器或对象的工厂，类是:org.springframework.beans.factory.BeanFactory，是一个接口类，主要定义一些接口的功能为子类来实现。ApplicationContext、ClassPathXmlApplicationContext、FileSystemXmlApplicationContext等，这些都是BeanFactory的各种功能实现。

类图：

方法说明：

public interface BeanFactory {

   /**
        * 通过该&将FactoryBean进行转义，通过&进行转义可以获取到工厂，否则则拿到工厂生成的对象。
    */
   String FACTORY_BEAN_PREFIX = "&";


   /**
    * 通过名称获取IOC容器中的bean
    */
   Object getBean(String name) throws BeansException;

   /**
    * 通过名称和Class类型获取IOC容器中的bean
    */
   <T> T getBean(String name, Class<T> requiredType) throws BeansException;

   /**
    * 通过class类型获取容器中的bean
    */
   <T> T getBean(Class<T> requiredType) throws BeansException;

   /**
        * 通过名称和对象获取bean
    */
   Object getBean(String name, Object... args) throws BeansException;

   /**
    * 
    */
   <T> T getBean(Class<T> requiredType, Object... args) throws BeansException;


   /**
    * 通过名称判断bean是否存在
    */
   boolean containsBean(String name);

   /**
    * 通过名称判断bean是否单例
    */
   boolean isSingleton(String name) throws NoSuchBeanDefinitionException;

   /**
    * 通过名称判断是否是原型bean
    */
   boolean isPrototype(String name) throws NoSuchBeanDefinitionException;

   /**
    * 通过名称和类型匹配是否一致 比如 user,User
    */
   boolean isTypeMatch(String name, ResolvableType typeToMatch) throws NoSuchBeanDefinitionException;

   /**
    * 同上
    */
   boolean isTypeMatch(String name, Class<?> typeToMatch) throws NoSuchBeanDefinitionException;

   /**
    * 返回给定名称bean的类型
    */
   Class<?> getType(String name) throws NoSuchBeanDefinitionException;

   /**
    * 获取bean的别名
    */
   String[] getAliases(String name);

}

1.ClassPathXmlApplicationContext 从类路径的xm文件载入上下文定义的信息

2.FileSystemXmlApplicationContext 从文件系统的xml文件载入上下文定义信息

代码实现：

版本：

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>4.3.11.RELEASE</version>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>4.3.11.RELEASE</version>
</dependency>

/**
 * @Auther: csh
 * @Date: 2020/7/7 17:56
 * @Description:用户信息
 */
public class User implements Serializable {
    private String userName;
    private int age;

    public User() {
    }

    public User(String userName, int age) {
        this.userName = userName;
        this.age = age;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "userName='" + userName + '\'' +
                ", age=" + age +
                '}';
    }
}

<?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">
    <!--通过属性注入-->
    <bean id="user" name="userTTTT" class="com.hong.spring.common.entity.User" >
        <property name="age" value="20" />
        <property name="userName" value="csh" />
    </bean>
</beans>

/**
 *
 * 功能描述:beanFactory测试
 *
 * @param:
 * @return:
 * @auther: csh
 * @date: 2020/7/8 18:36
 */
public class BeanFactoryTest {
    public static void main(String[] args) {
       //从类路径的xm文件载入上下文定义的信息
ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationfile*.xml");
System.out.println("context 已启动!");
User user = context.getBean(User.class,"user");
System.out.println("user信息："+user.toString()+":内存"+System.identityHashCode(user));
System.out.println("是否包含："+context.containsBean("user"));
System.out.println("是否单例："+context.isSingleton("user"));
System.out.println("是否一致!"+context.isTypeMatch("user",User.class));
Class <?> user1 = context.getType("user");
System.out.println(user1.toString());
System.out.println(Arrays.asList(context.getAliases("user")).toString());
//从文件系统的xml文件载入上下文定义信息
ApplicationContext context2 = new FileSystemXmlApplicationContext("src/main/resources/applicationfile*.xml");
User user2 = context2.getBean(User.class,"user");
System.out.println("user2信息:"+user2.toString()+":内存"+System.identityHashCode(user2));
    }

}

结果

七月 08, 2020 6:45:13 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@2e0fa5d3: startup date [Wed Jul 08 18:45:13 CST 2020]; root of context hierarchy
七月 08, 2020 6:45:13 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [D:\ideaWorkSpace\spring\target\classes\applicationfile-arg.xml]
七月 08, 2020 6:45:13 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [D:\ideaWorkSpace\spring\target\classes\applicationfile-scan.xml]
七月 08, 2020 6:45:13 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [D:\ideaWorkSpace\spring\target\classes\applicationfile-setter.xml]
context 已启动!
user信息：User{userName='csh', age=20}
是否包含：true
是否单例：true
是否一致!true
class com.hong.spring.common.entity.User
[userTTTT]
七月 08, 2020 6:45:13 下午 org.springframework.context.support.FileSystemXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.FileSystemXmlApplicationContext@612fc6eb: startup date [Wed Jul 08 18:45:13 CST 2020]; root of context hierarchy
七月 08, 2020 6:45:13 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [D:\ideaWorkSpace\spring\src\main\resources\applicationfile-arg.xml]
七月 08, 2020 6:45:13 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [D:\ideaWorkSpace\spring\src\main\resources\applicationfile-scan.xml]
七月 08, 2020 6:45:13 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [D:\ideaWorkSpace\spring\src\main\resources\applicationfile-setter.xml]
user2信息:User{userName='csh', age=20}

BeanFactory和FactoryBean的区别

spring的bean分为两种，一种为普通注入的bean，另外一种就是FactoryBean，两种bean是不一样，可以简单理解为一种是工厂(系统)的bean，一种是业务的bean。而想通过FactoryBean来getBean(id)来获取。

简单理解为：BeanFactory是个工厂，而FactoryBean是一个Bean而这个bean是可以能生产或者修饰对象生成的工厂bean。类位置：org.springframework.bean.factory.FactoryBean

类图

public interface FactoryBean<T> {

   /**
    * 获取对象
    */
   T getObject() throws Exception;

   /**
    * 获取类型
    */
   Class<?> getObjectType();

   /**
    * 是否单例
    */
   boolean isSingleton();

}

<?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">
    <!--通过属性注入-->
    <bean id="userFactory" name="userFactory2" class="com.hong.spring.beanfactory.FactoryBeanTest" >
    </bean>
</beans>

/**
 * @Auther: csh
 * @Date: 2020/7/8 19:28
 * @Description:测试factoryBean
 */
public class FactoryBeanTest implements FactoryBean<User> {
    public User getObject() throws Exception {
        return new User();
    }

    public Class <?> getObjectType() {
        return User.class;
    }

    public boolean isSingleton() {
        return true;
    }

    public static void main(String[] args) {
        BeanFactory bf = new ClassPathXmlApplicationContext("applicationfile-factorybean.xml");
        User user = (User)bf.getBean("userFactory");
        System.out.println(user);
    }

}

"C:\Program Files\Java\jdk1.8.0_181\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.3\lib\idea_rt.jar=51969:C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_181\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_181\jre\lib\rt.jar;D:\ideaWorkSpace\spring\target\classes;D:\mvn\org\springframework\spring-context\4.3.11.RELEASE\spring-context-4.3.11.RELEASE.jar;D:\mvn\org\springframework\spring-aop\4.3.11.RELEASE\spring-aop-4.3.11.RELEASE.jar;D:\mvn\org\springframework\spring-beans\4.3.11.RELEASE\spring-beans-4.3.11.RELEASE.jar;D:\mvn\org\springframework\spring-core\4.3.11.RELEASE\spring-core-4.3.11.RELEASE.jar;D:\mvn\commons-logging\commons-logging\1.2\commons-logging-1.2.jar;D:\mvn\org\springframework\spring-expression\4.3.11.RELEASE\spring-expression-4.3.11.RELEASE.jar;D:\mvn\org\springframework\spring-test\4.3.11.RELEASE\spring-test-4.3.11.RELEASE.jar" com.hong.spring.beanfactory.FactoryBeanTest
七月 08, 2020 7:31:34 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@685f4c2e: startup date [Wed Jul 08 19:31:34 CST 2020]; root of context hierarchy
七月 08, 2020 7:31:34 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationfile-factorybean.xml]
User{userName='null', age=0}

最后

BeanFactory是一个接口类，就是IOC(DI)的容器，它的实现负责将对象转化为bean，管理bean的整个生命周期。BeanFactory只能管理单例，当然如果若想实现多例，通过子类ApplicationContext获取可以在xml加添加scope="prototype"。

参考文献：

参考1

参考2

本文参与腾讯云自媒体分享计划，分享自微信公众号。

原始发表：2020-07-08，如有侵权请联系 cloudcommunity@tencent.com 删除

容器