spring bean作用域

概要：

实例代码具体解释：

文件夹结构

Car.java

package com.coslay.beans.autowire;

public class Car {
  private String brand;
  private double price;

  public String getBrand() {
    return brand;
  }

  public void setBrand(String brand) {
    this.brand = brand;
  }

  public double getPrice() {
    return price;
  }

  public void setPrice(double price) {
    this.price = price;
  }

  @Override
  public String toString() {
    return "Car [brand=" + brand + ", price=" + price + "]";
  }

  public Car(){
    System.out.println("Car's Constructor...");
  }

}

Main.java

package com.coslay.beans.scope;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.coslay.beans.autowire.Car;

public class Main {
  public static void main(String[] args) {
    ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-scope.xml");

    Car car = (Car) ctx.getBean("car");
    Car car2 = (Car) ctx.getBean("car");

    System.out.println(car == car2);
  }
}

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"
  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

  <!-- 
    使用bean的scope属性来配置bean的作用域
    singleton:默认值。容器初始化时创建bean实例，在整个容器的生命周期内仅仅创建这一个bean。单例的。
    prototype:原型的。容器初始化时不创建bean的实例。而在每次请求时都创建一个新的Bean实例。并返回。

  -->
  <bean id="car" class="com.coslay.beans.autowire.Car"
    scope="prototype">
    <property name="brand" value="Audi"></property>
    <property name="price" value="300000000"></property>
  </bean>

</beans>