Spring beans 销毁方法什么时候被调用？

Question

我已经在 bean 的“destroy-method”中放置了一条 sysout 语句。当我运行示例代码时，系统输出没有获得输出。这是否意味着销毁方法没有被调用？

测试类：

  package spring.test;

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

  public class InitTest {
    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("InitTestContext.xml");
        InitTestBean bean = (InitTestBean)ctx.getBean("InitTestBean");
        bean.display();
    }
  }

Bean

  package spring.test;

  public class InitTestBean {
    private String prop1;
    private String prop2;

    public InitTestBean(String prop1, String prop2) {
        System.out.println("Instantiating InitTestBean");
        this.prop1 = prop1;
        this.prop2 = prop2;
    }

    public void setProp1(String prop1) {
        System.out.println("In setProp1");
        this.prop1 = prop1;
    }

    public void setProp2(String prop2) {
        System.out.println("In setProp2");
        this.prop2 = prop2;
    }

    public String getProp1() {
        return prop1;
    }

    public String getProp2() {
        return prop2;
    }

    public void display() {
        System.out.println("Prop1 is " + prop1);
        System.out.println("Prop2 is " + prop2);
    }

    public void initialize(){
        System.out.println("In initialize");
        this.prop1 = "init-prop1";
        this.prop2 = "init-prop2";
    }

    public void teardown() {
        System.out.println("In teardown");
        this.prop1 = null;
        this.prop2 = null;
    }
  }

配置文件：

<?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:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="InitTestBean" class="spring.test.InitTestBean" init-method="initialize" destroy-method="teardown">
        <constructor-arg value="Prop1" />
        <constructor-arg value="Prop2" />
        <property name="prop1" value="setProp1"/>
        <property name="prop2" value="setProp2"/>
    </bean>

</beans>

Answer 1

您的示例不起作用，因为您没有关闭应用程序上下文，而只是让程序终止。

在上下文中调用 close()，您将看到正在调用 Bean 销毁方法。

Answer 2

对于OP来说可能为时已晚，但如果有人仍在寻找它...

close 方法位于 AbstractApplicationContext 而不是 ApplicationContext 中，另一种方法是使用ctx.registerShutdownHook() 而不是 ctx.close() 明显的原因是，在运行 Junit 时，您可能想要关闭上下文，但又不想关闭在生产环境中，让 Spring 决定何时关闭它。

Answer 3

仅当且仅当bean是单例实例时才调用“destroy-method”

请参阅IOC容器

INFO的日志输出：org.springframework.beans.factory.support.DefaultListableBeanFactory中的销毁单例 @1a0ce4c：定义bean [book1]；工厂层次结构的根

Answer 4

//Getting application context
ApplicationContext context = new ClassPathXmlApplicationContext(beansXML); 

//cleaning context
((ClassPathXmlApplicationContext) context).close(); 

Answer 5

您好，您需要将 ApplicationContext 更改为 AbstractApplicationContext ，然后注册到 ShutDownhook ，这将销毁您的 bean 并实现 DisposableBean 接口，例如

  package spring.test;

  import org.springframework.context.ApplicationContext;
  import org.springframework.context.support.ClassPathXmlApplicationContext;
  import org.springframework.context.support.AbstractApplicationContext;
  public class InitTest {
    public static void main(String[] args) {
       AbstractApplicationContext ctx = new ClassPathXmlApplicationContext("InitTestContext.xml");
  ctx.registerShutdownHook();
        InitTestBean bean = (InitTestBean)ctx.getBean("InitTestBean");
        bean.display();
    }
  }

：实现DisposableBean接口

package spring.test;
import org.springframework.beans.factory.DisposableBean;
  public class InitTestBean implements DisposableBean{
    private String prop1;
    private String prop2;
    public InitTestBean(String prop1, String prop2) {
        System.out.println("Instantiating InitTestBean");
        this.prop1 = prop1;
        this.prop2 = prop2;
    }
    public void setProp1(String prop1) {
        System.out.println("In setProp1");
        this.prop1 = prop1;
    }
    public void setProp2(String prop2) {
        System.out.println("In setProp2");
        this.prop2 = prop2;
    }
    public String getProp1() {
        return prop1;
    }
    public String getProp2() {
        return prop2;
    }
    public void display() {
        System.out.println("Prop1 is " + prop1);
        System.out.println("Prop2 is " + prop2);
    }
    public void initialize(){
        System.out.println("In initialize");
        this.prop1 = "init-prop1";
        this.prop2 = "init-prop2";
    }
    public void teardown() {
        System.out.println("In teardown");
        this.prop1 = null;
        this.prop2 = null;
    }
    @Override
    public void destroy() throws Exception {

        System.out.println(" the bean has been destroyed");
    }
  }

Answer 6

factory.destroySingletons(); 在您的 bean.display() 之后，作为 destroy-method 在 bean 定义中被赋值。创建 bean 的默认范围是单例，因此调用factory.destroySingletons() 将调用destroy-method 中提到的方法。