如何从不在Spring容器中的类访问Spring Bean的方法

本文介绍了如何从不在Spring容器中的类访问Spring Bean的方法的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我不是 Spring 专业版，所以请耐心等待....

我有三个班级：

class SpringBeanA { public aMethod（）{ ..... } } 类SpringBeanB { @Autowired SpringBeanA a; public bMethod（）{ a.method（）; } } class NONSpringClass { ..... b.method（）; ..... }

b .method（）在通过实例 SpringBeanB b = new SpringBeanB（）并通过自动装配SpringBeanB到NONSpringClass时，都会产生空指针错误。 / p>

自动装配：

class NONSpringClass { @Autowired SpringBeanB b; ..... b.method（）; ..... }

如何成功拨打 b.method（）？

解决方案

Spring初始化所有对象并保留它在Spring Application Context中。您可以通过几种不同的方式访问Application上下文中的对象。

首先创建一个spring配置类，将ApplicationContext注入私有属性并作为静态方法公开。

@Configuration class StaticApplicationContext实现ApplicationContextAware { static ApplicationContext applicationContext = null; public void setApplicationContext（ApplicationContext context）抛出BeansException { applicationContext = context; } / ** *请注意，这是一个静态方法，它暴露ApplicationContext ** / public static ApplicationContext getContext（）{ return的applicationContext; } }

现在你可以试试这个非spring类，

（（SpringBeanB）StaticApplicationContext.getContext.getBean（b））。bMethod（）;

请记住，在Spring上下文初始化之前调用getContext方法可能会导致NullPointerException。也不建议在弹簧容器外部访问bean。理想的方法是将所有豆子移到弹簧容器中进行管理。

如果你想从java Servelet访问SpringApplicationContext，请参考 WebApplicationContextUtils

I'm not a Spring pro, so please bear with me....

I have three classes:

class SpringBeanA { public aMethod() { ..... } } class SpringBeanB { @Autowired SpringBeanA a; public bMethod() { a.method(); } } class NONSpringClass { ..... b.method(); ..... }

b.method() gives a null pointer error, both when accesed via the instances SpringBeanB b = new SpringBeanB() and autowiring SpringBeanB to NONSpringClass.

The autowiring:

class NONSpringClass { @Autowired SpringBeanB b; ..... b.method(); ..... }

How can I successfully call b.method()?

解决方案

Spring initializes all the objects and keep it in Spring Application Context. You have couple different ways to get access to objects inside Application context

First create a spring configuration class to inject ApplicationContext in to a private attribute and expose as static method.

@Configuration class StaticApplicationContext implements ApplicationContextAware{ static ApplicationContext applicationContext = null; public void setApplicationContext(ApplicationContext context) throws BeansException { applicationContext = context; } /** * Note that this is a static method which expose ApplicationContext **/ public static ApplicationContext getContext(){ return applicationContext; } }

Now you can try this in your non spring class,

((SpringBeanB)StaticApplicationContext.getContext.getBean("b")).bMethod();

Please keep in mind, invoking getContext method before spring context initialization may cause NullPointerException. Also accessing beans outside of spring container is not a recommended approach. Ideal way will be to move all beans in to spring container to manage.

If you want to access SpringApplicationContext from a java Servelet please refer WebApplicationContextUtils