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bean实例化方式

程序员文章站 2022-05-23 18:41:12
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静态工厂

1工厂

package com.itheima.c_inject.b_static_factory;

public class MyBeanFactory {	
	/*
	 * 创建实例
	 * */
	public static UserService createService(){
		return new UserServiceImpl() ;
	}
}


2spring配置

<!-- bean definitions here -->
<!-- 
	将静态工厂创建的实例交给spring
	class: 确定静态工厂全限定类名
	factory-method:确定静态方法名
 -->
<bean id= "userServiceId"  class = "com.itheima.c_inject.b_static_factory.MyBeanFactory" factory-method="createService"></bean>
3测试

	@Test
	public void demo02(){
		//spring 工厂
		System.out.println("******");
		String xmlPath = "com/itheima/c_inject/b_static_factory/beans.xml";
		ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
		UserService userService = applicationContext.getBean("userServiceId" ,UserService.class);
		userService.addUser();
		
	}



实例工厂

1工厂
package com.itheima.c_inject.c_factory;

public class MyBeanFactory {	
	/*
	 * 创建实例
	 * */
	public  UserService createService(){ //非静态
		return new UserServiceImpl() ;
	}
}

2配置文件
<!-- bean definitions here -->
<!-- 创建工厂实例 -->
<bean id = "myBeanFactoryId" class = "com.itheima.c_inject.c_factory.MyBeanFactory"></bean>
<!-- 获得userService
	factory-bean 确定工厂实例
	factory-method 确定普通方法
 -->
<bean id = "userServiceId" factory-bean="myBeanFactoryId"  factory-method="createService"></bean>

3测试
	@Test
	public void demo02(){
		//spring 工厂
		System.out.println("******");
		String xmlPath = "com/itheima/c_inject/c_factory/beans.xml";
		ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
		UserService userService = applicationContext.getBean("userServiceId" ,UserService.class);
		userService.addUser();
		
	}