获取JavaBean的方法有那些

1-- ApplicationContext context = new FileSystemXmlApplicationContext("web/WEB-INF/classes/spring_*.xml");
2--ApplicationContext context=new ClassPathXmlApplicationContext("pring_*.xml");
3--WebApplicationContext context = ContextLoader.getCurrentWebApplicationContext();  部分类里Spring无法注入bean时可以用这种

推荐通过实现ApplicationContextAware接口，获取ApplicationContext，然后通过getBeansOfType获取

继承ApplicationContextAware 来获取Bean

package com.example;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
public class ApplicationContextUtil implements ApplicationContextAware {
    private static ApplicationContext applicationContext;
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException{
        this.applicationContext = applicationContext;
    }
    public static ApplicationContext getContext() {
        return applicationContext;
    }
    public static <T> T getBean(String name) {
        if (applicationContext == null) {
            return null;
        }
        return (T) applicationContext.getBean(name);
    }
}

将ApplicationContextAware 配置进application-context.xml

<bean id="applicationContextUtil" class="com.example.ApplicationContextUtil"/>

在需要的地方获取bean

TestBean testBean = ApplicationContextUtil.getBean("testBean");

使用ContextLoader 获取bean

ApplicationContext app = ContextLoader.getCurrentWebApplicationContext();
TestBean testBean = app.getBean("testBean", TestBean.class);

继承 BeanFactoryAware 获取bean
在单元测试时，像dubbo filter这种场景，只能使用Spring 容器来获取bean了， 示例如下：

创建一个类继承BeanFactoryAware

package com.example;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;

public class SpringBeanFactory implements BeanFactoryAware {
    private static BeanFactory beanFactory;
    @Override
    public void setBeanFactory(BeanFactory factory) throws BeansException {
        this.beanFactory = factory;
    }

    /**
     * 根据beanName名字取得bean
     * @param name
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name) {
        if (beanFactory == null) {
            return null;
        }
        return (T) beanFactory.getBean(name);
    }
}

SpringBeanFactory 配置进application-context.xml

<bean id="springBeanFactory" class="com.example.SpringBeanFactory"/>

在需要的地方获取bean

TestBean testBean = SpringBeanFactory.getBean("testBean");