spring 三种对象创建方式

约定不等于承诺〃 2022-05-22 04:59 229阅读 0赞

## 一、XML配置文件 ##

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns="http://www.springframework.org/schema/beans" 
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-4.2.xsd ">
    	
    	
    	
    	
    		 
    	
    <bean name="user" class="com.lzp.bean.User" ></bean>
    	
    	
    	
    	<bean name="user2" class="com.lzp.create.UserFactory" factory-method="createFactory"></bean>
    		
    		
    		
    	<bean name="user3" factory-bean="userFactory" factory-method="createUser"></bean>
    	<bean name="userFactory" class="com.lzp.create.UserFactory"></bean>
    		
    		
    		<import resource="com/lzp/create/applicationContext.xml"/>
    	
    </beans>

### `二、测试类` ###

package com.lzp.create;
    
    import org.junit.jupiter.api.Test;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    import com.lzp.bean.User;
    
    public class Demo {
    		//创建方式一，空参构造创建
    		@Test
    		public void test() {
    		//1、创建容器对象
    		ApplicationContext app = new ClassPathXmlApplicationContext("com/lzp/create/applicationContext.xml");
    		//2、向容器“要”user对象
    		User bean = (User) app.getBean("user"); 
    		
    		
    		//打印user对象
    		System.out.println(bean);
    	}
    		//创建方式二，静态工厂创建
    		@Test
    		public void test2() {
    			//1、创建容器对象
    			ApplicationContext app = new ClassPathXmlApplicationContext("com/lzp/create/applicationContext.xml");
    			//2、向容器“要”user对象
    			User bean = (User) app.getBean("user2"); 
    			//打印user对象
    			System.out.println(bean);
    		}
    		
    			//创建方式三，实例工厂创建
    				@Test
    				public void test3() {
    					//1、创建容器对象
    					ApplicationContext app = new ClassPathXmlApplicationContext("com/lzp/create/applicationContext.xml");
    					//2、向容器“要”user对象
    					User bean = (User) app.getBean("user3"); 
    					//打印user对象
    					System.out.println(bean);
    				}
    
    }