自定义实现Spring Scope扩展

本文简单介绍实现Scope扩展的方法，其实很简单只要实现Scope接口，并通过beanfactory的registerScope将自定义scope 注册到Spring容器。

Spring Scope

Scope	描述
singleton	默认spring 容器管理的bean 都是单例
prototype	定义任意数量的对象实例
request	只有web容器才有，一个http 请求对应一个对象实例
session	只有web容器才有，每一个http session 对应一个对象实例.
application	只有web容器才有， ServletContext 对应个对象实例.
websocket	只有web容器才有，将单个 Bean 定义的范围限定为 WebSocket 的生命周期

自定义TenantScope --实现Scope 类

public class TenantScope implements Scope {

    private Map<String, Object> scopedObjects = Collections.synchronizedMap(new HashMap<String, Object>());
    private Map<String, Runnable> destructionCallbacks = Collections.synchronizedMap(new HashMap<String, Runnable>());

    @Override
    public Object get(String name, ObjectFactory<?> objectFactory) {
        if (!scopedObjects.containsKey(name)) {
            scopedObjects.put(name, objectFactory.getObject());
        }
        return scopedObjects.get(name);
    }
    @Override
    public Object remove(String name) {
        destructionCallbacks.remove(name);
        return scopedObjects.remove(name);
    }

    @Override
    public void registerDestructionCallback(String name, Runnable callback) {
        destructionCallbacks.put(name, callback);
    }

    @Override
    public Object resolveContextualObject(String key) {
        return null;
    }

    @Override
    public String getConversationId() {
        return "tenant";
    }
}

实现注册到容器

public class TenantBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory factory) throws BeansException {
        factory.registerScope("tenant", new TenantScope());
    }
}

编写测试demo

定义tenantBean

public class TenantBean {

    private final String name;

    public TenantBean(String name) {
        this.name = name;
    }
    public void pringName() {
        System.out.println(String.format("Tenant from %s of type %s", this.name, this.getClass().getName()));
    }
}

配置TenantBeanFactoryPostProcessor

@Configuration
public class TenantScopeConfig {

    @Bean
    public static BeanFactoryPostProcessor beanFactoryPostProcessor() {
        return new TenantBeanFactoryPostProcessor();
    }
}

定义两个TenantBean的实例

@Configuration
public class TenantBeansConfig {

    @Scope(scopeName = "tenant")
    @Bean
    public TenantBean foo() {
        return new TenantBean("foo");
    }

    @Scope(scopeName = "tenant")
    @Bean
    public TenantBean bar() {
        return new TenantBean("bar");
    }
}

运行springboot 项目，并获取TenantBean对应实例化的两个bean，并调用printName方法

@SpringBootApplication
public class SpringbootScopeDemoApplication {
    public static void main(String[] args) {
        
            ConfigurableApplicationContext ctx= SpringApplication.run(SpringbootScopeDemoApplication .class, args);
                 TenantBean foo = (TenantBean) ctx.getBean("foo", TenantBean.class);
            foo.pringName();
            TenantBean bar = (TenantBean) ctx.getBean("bar", TenantBean.class);
            bar.pringName();
    }
}