引言

Spring的Ioc容器，用於解決程式之間的耦合，通過配置檔案和反射獲取物件。（工廠模式思想）

框架自帶工廠模式

配置檔案

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="accountService" class="com.czy.service.impl.AccountServiceImpl"></bean>

    <bean id="accountDao" class="com.czy.dao.impl.AccountDaoImpl"></bean>
</beans>
 

通過配置檔案與對映獲取物件(單例物件)

package com.czy.ui;

import com.czy.service.AccountService;
import com.czy.service.impl.AccountServiceImpl;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * 模擬儲存賬戶
 */
public class Client {
    /**
     * 獲取spring的Ioc核心容器，並根據id獲取物件
     * @param args
     */
    public static void main(String[] args){
        //1.獲取核心容器物件
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");

        //2.根據id獲取bean物件
        AccountService service0 = ac.getBean("accountService",AccountService.class);
        AccountService service = (AccountService)ac.getBean("accountService");

        System.out.println(service0);
        System.out.println(service);
    }
}

 

Application三個常用實現類（BeanFactory）

1.ClassPathXmlApplicationContext

它可以載入類路徑下的配置檔案，要求配置檔案必須在類路徑下。不在的話，載入不了（maven工程裡的resources）

        //1.獲取核心容器物件
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");

        //2.根據id獲取bean物件
        AccountService service0 = ac.getBean("accountService",AccountService.class);
        AccountService service = (AccountService)ac.getBean("accountService");
 

2.FileSystemXmlApplicationContext

它可以載入磁碟任意路徑下的配置檔案（必須有訪問許可權）

//1.獲取核心容器物件
        ApplicationContext ac = new FileSystemXmlApplicationContext("E:\\JAVA\\Spring\\day01_eesy_02Spring\\src\\main\\resources\\bean.xml");

        //2.根據id獲取bean物件
        AccountService service0 = ac.getBean("accountService",AccountService.class);
        AccountService service = (AccountService)ac.getBean("accountService");

3.AnnotationConfigApplicationContext

它用於讀取註解建立容器的。