Car.java
package com.gong.spring.beans.autowire;
public class Car {
public Car() {
}
public Car(String name) {
this.name = name;
}
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Car [name=" + name + "]";
}
}
beans-scope.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="car" class="com.gong.spring.beans.autowire.Car" p:name="baoma"></bean>
</beans>
Main.java
package com.gong.spring.beans.autowire;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Main {
public static void main(String[] args) {
//1.创建spring的IOC容器对象
ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-scope.xml");
//2.从容器中获取Bean实例
Car car = (Car) ctx.getBean("car");
Car car2 = (Car) ctx.getBean("car");
System.out.println(car == car2);
System.out.println(car.toString());
}
}
输出:
默认情况下,在xml文件中配置的bean都是单例模式,即实例化这个相同类型的bean时,返回的是同一个对象,即实例化IOC容器ctx时,就已经创建好了一个唯一的bean。我们可以在xml中设置scope属性的值来改变bean的作用域。
<bean id="car" class="com.gong.spring.beans.autowire.Car" p:name="baoma" scope="prototype"></bean>
scope有四种值:
默认的就是singleleton,在指定为prototype之后,每次实例化的对象就不是同一个bean了。