spring源码学习（一）spring复习之IOC

Spring的核心思想

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IOC

1、BeanFactory

示例
    public static void main(String[] args) {
        //bean工厂
        DefaultListableBeanFactory beanFactory =new DefaultListableBeanFactory();
        //xml读取
        XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);
        //读取xml
        reader.loadBeanDefinitions("beans.xml");
        UserService userService =(UserService) beanFactory.getBean("userService");
        System.out.println(userService);
    }

xml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 id="userService" class="com.cdc.service.UserServiceImpl">
    </bean>
</beans>
1.1、set注入

xml文件

    <bean id="userService" class="com.cdc.service.impl.UserServiceImpl">
        <property name="abcDao" ref="userDao"></property>
    </bean>
    <bean id="userDao" class="com.cdc.dao.impl.UserDaoImpl">
    </bean>

UserDaoImpl.java

public class UserDaoImpl implements UserDao {
}

UserServiceImpl.java

public class UserServiceImpl implements UserService {
    public void setAbcDao(UserDao userDao){
        System.out.println("set注入啦:"+userDao);
    }
}

测试文件

public class TestSpringIOC {

    public static void main(String[] args) {
        //bean工厂
        DefaultListableBeanFactory beanFactory =new DefaultListableBeanFactory();
        //xml读取
        XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);
        //读取xml
        reader.loadBeanDefinitions("beans.xml");
        UserService userService =(UserService) beanFactory.getBean("userService");
        System.out.println(userService);
    }
}

输出：

set注入啦:com.cdc.dao.impl.UserDaoImpl@56de5251
com.cdc.service.impl.UserServiceImpl@419c5f1a
  • 注意set方法注入关键，set方法名，后面第一个字母转小写，要跟<property name="abcDao" ，里面的name对应好

2、ApplicationContext （一）

    <bean id="userService" class="com.cdc.service.impl.UserServiceImpl">
        <property name="abcDao" ref="userDao"></property>
    </bean>

    <bean id="userDao" class="com.cdc.dao.impl.UserDaoImpl">
    </bean>

public class TestApplicationContext {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService =(UserService) applicationContext.getBean("userService");
        System.out.println(userService);
    }
}
通配符方式加载多个配置文件

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3、ApplicationContext与BeanFactory关系

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  • ApplicationContext内部有个BeanFactory接口的实现类DefaultListableBeanFactory

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  • DefaultListableBeanFactory内部有个beanDefinitionMap，是bean的定义信息集合，现在有2个bean

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  • DefaultListableBeanFactory内部有个singletonObjects，是单例池，里面放的是具体的bean

spring web的ApplicationContext

后面再翻看
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4、ApplicationContext （二）

4.1、别名

    <bean class="com.cdc.service.impl.UserServiceImpl">
        <property name="abcDao" ref="userDao"></property>
    </bean>

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  • 之前配置的id即bean的别名，getBean("userService")，就是通过别名获取的。
  • 没有配id，默认别名就是类的全限定名，通过这样的方式获取bean，
    UserService userService =(UserService) applicationContext.getBean("com.cdc.service.impl.UserServiceImpl");

4.1.1取多个别名

    <bean id="userService" name="aaa,ccc,bbb" class="com.cdc.service.impl.UserServiceImpl">
        <property name="abcDao" ref="userDao"></property>
    </bean>

    <bean id="userDao" class="com.cdc.dao.impl.UserDaoImpl">
    </bean>

public class TestApplicationContext {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService =(UserService) applicationContext.getBean("userService");
        UserService userService2 =(UserService) applicationContext.getBean("aaa");
        UserService userService3 =(UserService) applicationContext.getBean("bbb");
        UserService userService4 =(UserService) applicationContext.getBean("ccc");
        System.out.println(userService);
        System.out.println(userService2);
        System.out.println(userService3);
        System.out.println(userService4);
    }
}

默认别名是id
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BeanFactory内部有个aliasMap，可以进行别名的映射
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4.1.2 没有配置id时，默认别名取第一个 aaa

    <bean name="aaa,ccc,bbb" class="com.cdc.service.impl.UserServiceImpl">
        <property name="abcDao" ref="userDao"></property>
    </bean>

4.2 scope 作用范围

4.2.1默认单例

    <bean id="userService" class="com.cdc.service.impl.UserServiceImpl">
    </bean>

4.2.2可原型模式

    <bean id="userService" class="com.cdc.service.impl.UserServiceImpl" scope="prototype">
    </bean>

public class TestApplicationContext {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService =(UserService) applicationContext.getBean("userService");
        UserService userService2 =(UserService) applicationContext.getBean("userService");
        UserService userService3 =(UserService) applicationContext.getBean("userService");
        System.out.println(userService);
        System.out.println(userService2);
        System.out.println(userService3);
    }
}

输出：

com.cdc.service.impl.UserServiceImpl@43195e57
com.cdc.service.impl.UserServiceImpl@333291e3
com.cdc.service.impl.UserServiceImpl@479d31f3

4.3延迟加载

    <bean id="userService" class="com.cdc.service.impl.UserServiceImpl" lazy-init="true">
    </bean>
创建容器后，单例池singletonObjects没有bean，执行了getBean方法时，才创建bean放进单例池。
        //1.创建容器
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        //2.从容器中取bean
        UserService userService =(UserService) applicationContext.getBean("userService");
        System.out.println(userService);
  • 注意，创建容器后，beanDefinitionMap是有userService的bean定义信息的

4.4 读取多个xml配置文件，以及根据类型获取bean

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4.5 spring是默认调用bean的无参构造方法实例化的

public class UserServiceImpl implements UserService {

    public UserServiceImpl(){
        System.out.println("实例化，调用无参构造");
    }

    private UserDao userDao;

    //set注入，set后面的字符串
    public void setAbcDao(UserDao userDao){
        this.userDao=userDao;
        System.out.println("set注入啦:"+userDao);
    }

}

public class TestApplicationContext {
    public static void main(String[] args) {
        //1.创建容器，可以根据多个配置文件创建
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        //2.从容器中取bean
        UserService userService =(UserService) applicationContext.getBean("userService");
        System.out.println(userService);
    }
}

输出:

实例化，调用无参构造
com.cdc.service.impl.UserServiceImpl@123ef382

4.6构造注入

public class UserServiceImpl implements UserService {

    public UserServiceImpl(){
        System.out.println("实例化，调用无参构造");
    }

    public UserServiceImpl(String name,int num){
        System.out.println("实例化，调用有参构造"+name+num);
    }

    private UserDao userDao;

    //set注入，set后面的字符串
    public void setAbcDao(UserDao userDao){
        this.userDao=userDao;
        System.out.println("set注入啦:"+userDao);
    }

}

    <bean id="userService" class="com.cdc.service.impl.UserServiceImpl">
        <constructor-arg name="name" value="nihao"></constructor-arg>
        <constructor-arg name="num" value="60"></constructor-arg>
        <property name="AbcDao" ref="userDao"></property>
    </bean>

    <bean id="userDao" class="com.cdc.dao.impl.UserDaoImpl">
    </bean>

输出：

实例化，调用有参构造nihao60
set注入啦:com.cdc.dao.impl.UserDaoImpl@22555ebf
com.cdc.service.impl.UserServiceImpl@4d1c00d0

4.7 静态方法工厂加载Bean

public class BookFactory {

    public static BookDTO bookDTOBuild(String carName,int num){
        //使用静态方法注入
        //可以在此处写点别的代码
        return new BookDTO();
    }
}

springBook.xml

    <bean id="book" class="com.cdc.factory.BookFactory" factory-method="bookDTOBuild">
            <!--构造参数注入-->
            <constructor-arg name="carName" value="benz"></constructor-arg>
            <constructor-arg name="num" value="60"></constructor-arg>
    </bean>

public class TestApplicationContextFactory {
    public static void main(String[] args) {
        //1.创建容器，可以根据多个配置文件创建
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("springBook.xml");
        //2.从容器中取bean
        BookDTO bookDTO =(BookDTO) applicationContext.getBean("book");
        System.out.println(bookDTO);
    }
}

4.8 实例方法工厂加载Bean

public class MyBeanFactory2 {
    public UserDao userDao(String carName,int num){
        return new UserDaoImpl();
    }
}

    <bean id="myBeanFactory2" class="com.cdc.factory.MyBeanFactory2"></bean>

    <bean id="userDao2" factory-bean="myBeanFactory2" factory-method="userDao">
             <!--构造参数注入-->
            <constructor-arg name="carName" value="benz"></constructor-arg>
            <constructor-arg name="num" value="60"></constructor-arg>
    </bean>

        UserDao userDao2 =(UserDao) applicationContext.getBean("userDao2");
        System.out.println(userDao2);
  • 配置实例化工厂类，实例化工厂类来产生bean
与静态方法工厂的区别

实例化工厂类也要进单例池
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4.9FactoryBean实现延迟加载

public class MyBeanFactory3 implements FactoryBean<UserDao> {

    @Override
    public UserDao getObject() throws Exception {
        return new UserDaoImpl();
    }

    @Override
    public Class<?> getObjectType() {
        return UserDao.class;
    }
}

<bean id="userDao3" class="com.cdc.factory.MyBeanFactory3"></bean>
4.9.1 执行了ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");单例内不会有userDao3的实例，只会有一个实现FactoryBean接口的实例

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4.9.2 执行了UserDao userDao3 =(UserDao) applicationContext.getBean("userDao3");才会在缓冲池内有个userDao3的实例，下次getBean，也是从该缓冲池取

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4.10属性注入集合、数据

4.10.1List<String>集合

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4.10.2.1对象集合，集合内代表三个不同的UserDaoImpl实例

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4.10.2.2对象集合，也可配置在外面

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set String集合

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set 对象集合

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map 集合

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properties对象

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4.11 自动注入

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1.通过名字自动注入

public class UserServiceImpl implements UserService {
    public void setUserDao3(UserDao userDao){
        System.out.println("set注入userDao:"+userDao);
    }
}

    <beans>
        <bean id="UserService" class="com.cdc.service.impl.UserServiceImpl" autowire="byName"></bean>
        <bean id="userDao3" class="com.cdc.dao.impl.UserDaoImpl"></bean>
    </beans>
  • set方法后面的名字一定要和bean的id（name）一致
    2.通过类型自动注入
    <beans>
        <bean id="UserService" class="com.cdc.service.impl.UserServiceImpl" autowire="byType"></bean>
        <bean id="userDao3" class="com.cdc.dao.impl.UserDaoImpl"></bean>
    </beans>

4.12 命名空间

4.12.1 spring默认的命名空间

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4.12.2 引入其他的命名空间

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4.12.2.1 接着就可以使用其他的标签了

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4.12.3

4.12.3.1

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4.12.3.2

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4.12.3.3

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4.12.4

4.12.4.1

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4.12.4.2

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4.12.4.3

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4.13 profile环境标签

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指定test，可以获取userDao1

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不指定环境，只能获取到userService和userDao

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  • 指定dev,可以获取userService1、userService和userDao
  • 指定test,可以获取userDao1、userService和userDao
  • 上图红色框框的相当于公共部分

4.13 import标签

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4.13.1 示例

applicationContext.xml文件
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只读取applicationContext.xml文件，就可以读取到applicationContext-order.xml和applicationContext-user.xml配置的bean
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4.14 alias别名标签

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4.15 使用容器注册bean

posted @ 2026-03-05 09:16  dvdhellohaha  阅读(15)  评论(0)    收藏  举报