Spring Framework_学习记录_05

忘是亡心i 2022-03-07 11:14 141阅读 0赞

### 1.在bean内部注入 ###

*  DrawingApp.java

package org.zcs.spring;
    
    import org.springframework.beans.factory.BeanFactory;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    import org.springframework.context.support.FileSystemXmlApplicationContext;
     
    
    public class DrawingApp { 
    
    	public static void main(String[] args) { 
    		// TODO Auto-generated method stub
    		//BeanFactory factory = new FileSystemXmlApplicationContext("src/spring.xml");
    		//Triangle triangle = new Triangle();
    		ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
    		Triangle triangle = (Triangle)context.getBean("triangle");
    		triangle.draw();
    	}
    }

*  Triangle.java

package org.zcs.spring;
    
    public class Triangle { 
    	private Point pointA;
    	private Point pointB;
    	private Point pointC;
    	public String getTest() { 
    		return test;
    	}
    	public void setTest(String test) { 
    		this.test = test;
    	}
    	private String test;
    	public Point getPointA() { 
    		return pointA;
    	}
    	public void setPointA(Point pointA) { 
    		this.pointA = pointA;
    	}
    	public Point getPointB() { 
    		return pointB;
    	}
    	public void setPointB(Point pointB) { 
    		this.pointB = pointB;
    	}
    	public Point getPointC() { 
    		return pointC;
    	}
    	public void setPointC(Point pointC) { 
    		this.pointC = pointC;
    	}
    	public void draw () { 
    		System.out.println("This is Point A: (" +getPointA().getX()  +"," + (getPointA().getY()) +")");
    		System.out.println("This is Point B: (" +getPointB().getX()  +"," + (getPointB().getY()) +")");
    		System.out.println("This is Point C: (" +getPointC().getX()  +"," + (getPointC().getY()) +")");
    		 System.out.println(this.test);
    		
    	}
    }

*  spring.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
       
       	<bean id = "triangle" class= "org.zcs.spring.Triangle"  name = "triangle-name">
     		 <property name="pointA"  ref = "zeroPoint" >
     
     		 </property>
     		 <property name="test" >
     			<idref bean = "zeroPoint"/>
     		 </property>
     		 <property name="pointB" >
    		 		<bean id= "twoPoint" class = "org.zcs.spring.Point">
    			   		<property name="x"  value = "20"></property>
    			   		<property name="y"  value = "0"></property>
    		   		</bean>
     		 </property>
     		 
     		 <property name="pointC" >
     		 	   	<bean id= "threePoint" class = "org.zcs.spring.Point">
    		   			<property name="x"  value = "0"></property>
    		   			<property name="y"  value = "20"></property>
       				</bean>
     		 </property>
       	</bean>
       	
       	<bean id= "zeroPoint" class = "org.zcs.spring.Point">
       		<property name="x"  value = "0"></property>
       		<property name="y"  value = "0"></property>
       	</bean>
       	<alias name="triangle-name" alias="triangle-alias"/>
       	
      </beans>

### 2.学习笔记 ###

*  本次学习了在Beans内部注入对象实例。
 *  学习了如何定义别名。
 *  认识了idref与ref的区别。

#### 3.问题记录 ####

*  idref注入的只是目标bean的id，而不是目标bean的实例，同时使用idref容器在部署的时候还会验证这个名称是否存在。  
    其实idref就跟value一样，只是将某个字符串注入到属性或者构造函数中，只不过注入的是某个bean定义的id属性值。
 *  但是ref则不同，ref元素是将目标bean定义的实例注入到属性或者构造函数中，