Spring bean引用跨多个线程

Question

I have come across a scenario as below:

MyBean - Defined in XML Configuration.

I need to inject MyBean into multiple threads. But my requirements is: 1) The reference retrieved in two different threads should be different 2) But I should get the same reference irrespective how many times I retrieve bean from single thread.

Eg :

Thread1 {

    run() {
        MyBean obj1 = ctx.getBean("MyBean");
        ......
        ......
        MyBean obj2 = ctx.getBean("MyBean");
    }
}

Thread2 {

    run(){
        MyBean obj3 = ctx.getBean("MyBean");
    }
}

So Basically obj1 == obj2 but obj1 != obj3

Answer 1

You can use the custom scope named SimpleThreadScope .

From the Spring documentation :

As of Spring 3.0 , a thread scope is available, but is not registered by default. For more information, see the documentation for SimpleThreadScope . For instructions on how to register this or any other custom scope, see Section 3.5.5.2, “Using a custom scope” .

Here an example of how to register the SimpleThreadScope scope :

Scope threadScope = new SimpleThreadScope();
beanFactory.registerScope("thread", threadScope);

Then, you'll be able to use it in your bean's definition :

<bean id="foo" class="foo.Bar" scope="thread">

You can also do the Scope registration declaratively :

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

    <bean class="org.springframework.beans.factory.config.CustomScopeConfigurer">
        <property name="scopes">
            <map>
                <entry key="thread">
                    <bean class="org.springframework.context.support.SimpleThreadScope"/>
                </entry>
            </map>
        </property>
    </bean>

    <bean id="foo" class="foo.Bar" scope="thread">
        <property name="name" value="bar"/>
    </bean>

</beans>

Answer 2

What you require is a new Thread Local custom scope . You can either implement your own or use the one here .

The Custom Thread Scope module is a custom scope implementation for providing thread scoped beans. Every request for a bean will return the same instance for the same thread.