Spring---Bean的生命周期及作用域(四)

最新推荐文章于 2021-09-07 17:22:07 发布

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#SSH #Spring #SSM #Java

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1.Spring容器的作用：

Spring容器只能管理singleton作用域Bean的生命周期，Spring容器知道Bean何时创建、何时初始化、何时销毁。

2.Spring初始化bean的过程，代码演示如下：

1.创建Phone.java类

package com.learnSpring08;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
public class Phone implements BeanNameAware,ApplicationContextAware,InitializingBean{

    private int id;
    private String name;
    private double price;

    public Phone(){

        System.out.println("Spring创建Phone对象实例");
    }

    public void setId(int id) {
        System.out.println("Spring调用setId()方法执行依赖注入id值"); 
        this.id = id;
    }

    public void setName(String name) {
        System.out.println("Spring 调用setName()方法执行依赖注入name值");
        this.name = name;
    }

    public void setPrice(double price) {
        System.out.println("Spring 调用setPrice()方法执行依赖注入price");
        this.price = price;
    }

    @Override
    public String toString() {
        return "Phone [id=" + id + ", name=" + name + ", price=" + price + "]";
    }

    public void init(){

        System.out.println("正在执行初始化init()方法....");
    }


    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("正在执行初始化方法afterPropertiesSet() ");

    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        System.out.println("设置bean的应用上下文");

    }

    @Override
    public void setBeanName(String name) {
        System.out.println("设置bean的名字");

    }

}

2.配置bean07.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">

   <bean id="phone"  class="com.learnSpring08.Phone" init-method="init">

   <property name="id"  value="6666"></property>
   <property name="name"  value="华为"></property>
   <property name="price"  value="4999"></property>

   </bean>

</beans>

3.测试

package com.learnSpring08;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support
.ClassPathXmlApplicationContext;
public class testPhone {

    @Test
    public void testDemo(){
        ApplicationContext context=new
        ClassPathXmlApplicationContext("bean07.xml");
        Phone p=context.getBean("phone",Phone.class);

    }

}

控制台输出结果为：

Spring创建Phone对象实例
Spring调用setId()方法执行依赖注入id值
Spring 调用setName()方法执行依赖注入name值
Spring 调用setPrice()方法执行依赖注入price
设置bean的名字
设置bean的应用上下文
正在执行初始化方法afterPropertiesSet() 
正在执行初始化init()方法....


总结：从输出结果可以看出Spring容器创建一个bean实例的全部过程。

3.Spring销毁bean的全过程

1.创建Phone.java类

package com.learnSpring08;
import org.springframework.beans.factory.DisposableBean;
public class Phone implements DisposableBean{

    private int id;
    private String name;
    private double price;

    public Phone(){

        System.out.println("Spring创建Phone对象实例");
    }

    public void setId(int id) {
        System.out.println("Spring调用setId()方法执行依赖注入id值"); 
        this.id = id;
    }

    public void setName(String name) {
        System.out.println("Spring 调用setName()方法执行依赖注入name值");
        this.name = name;
    }

    public void setPrice(double price) {
        System.out.println("Spring 调用setPrice()方法执行依赖注入price");
        this.price = price;
    }

    @Override
    public String toString() {
        return "Phone [id=" + id + ", name=" + name + ", price=" + price + "]";
    }

    public void close(){

        System.out.println("正在执行初始化close()方法....");
    }



    @Override
    public void destroy() throws Exception {

        System.out.println("正在执行销毁之前的方法destroy()");
    }

}

2.配置bean07.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/schem/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
   <bean id="phone"  class="com.learnSpring08.Phone"
    destroy-method="close">
     <property name="id"  value="6666"></property>
     <property name="name"  value="华为"></property>
     <property name="price"  value="4999"></property>
  </bean>
</beans>

3.测试

package com.learnSpring08;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class testPhone {

    @Test
    public void testDemo(){
        ApplicationContext context=new ClassPathXmlApplicationContext("bean07.xml");
        Phone p=context.getBean("phone",Phone.class);
        ((AbstractApplicationContext) context).close();
    }

}


控制台输出结果为：

Spring创建Phone对象实例
Spring调用setId()方法执行依赖注入id值
Spring 调用setName()方法执行依赖注入name值
Spring 调用setPrice()方法执行依赖注入price
八月 17, 2017 11:15:36 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@6ed3ef1: startup date [Thu Aug 17 11:15:36 CST 2017]; root of context hierarchy
正在执行销毁之前的方法destroy()
正在执行初始化close()方法....