## 無參構造器方式(建議使用這種方式) 就是前面使用的方式. ## 靜態工廠方式 條件:需要有一個工廠類,在這個工廠類中還需要有一個靜態方法. 配置文件: ~~~ <!--指定id,指定工廠類,指定方法--> <bean id="user" class="com.like.domain.BeanFactory" factory-method="createUser"/> ~~~ 工廠: ~~~ package com.like.domain; public class BeanFactory { public static User createUser() { return new User(); } } ~~~ 調用: ~~~ public class main { public static void main(String[] args) { ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml"); User user1 = (User) applicationContext.getBean("user"); User user2 = (User) applicationContext.getBean("user"); System.out.println(user1); //這兩個對象是同一個,因為是單例工廠獲得到的對象. System.out.println(user2); } } ~~~ ## 實例工廠方式 ~~~ <!--指定id,指定工廠類.先有一個工廠--> <bean id="BeanFactory" class="com.like.domain.BeanFactory"/> <!--再指定工廠創建user對象--> <bean id="user" factory-bean="BeanFactory" factory-method="createUser"/> ~~~ ~~~ public class BeanFactory { public User createUser() { return new User(); } } ~~~ ~~~ public class main { public static void main(String[] args) { ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml"); User user1 = (User) applicationContext.getBean("user"); User user2 = (User) applicationContext.getBean("user"); System.out.println(user1); System.out.println(user2); } } ~~~