在多线程类中，Spring注入对象为null问题处理

在开发中经常会使用spring的@Autowired或@Resource来实现对象的自动注入，但是在最近的开发中在多线程中用Spring来自动注入时总是注入不进去，对象显示为null。

后来了解到 spring bean 出于线程安全考虑，不得注入bean至线程类（Runnable），如果线程中想使用spring实例，有两种方法：

1、将ThreadTest类也作为一个bean注入到spring容器中:

public class SpringMultiThreadTest{    
    @Autowired  
    private ThreadTest threadTest;  //将线程类作为对象注入  
    @Test    
    public void testSpringBean(){    
        for (int i=0; i<10000000; i++){    
            new Thread(threadTest).start();    
        }    
        try {    
            Thread.sleep(1000);    
        }catch (InterruptedException e){    
            e.printStackTrace();    
        }    
    }    
}

2、使用Spring手动获得ServiceBean:

   (1)先写一个手动获得Spring bean的工具类

public class SpringBeanUtil implements ApplicationContextAware{    
        
    private static ApplicationContext applicationContext = null;    
    
    @Override    
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {    
        SpringBeanUtil.applicationContext = applicationContext;    
    }    
    
    public static Object getBeanByName(String beanName) {    
        if (applicationContext == null){    
            return null;    
        }    
        return applicationContext.getBean(beanName);    
    }    
    
    public static  T getBean(Class type) {    
        return applicationContext.getBean(type);    
    }    
    
}

   (2)ThreadTest类中不自动获取，而是手动获取

public class ThreadTest implements Runnable{    
    private ServiceBean serviceBean;    
    private static AtomicInteger count = new AtomicInteger(0);    
    public ThreadRunner(){    
        this.serviceBean = (ServiceBean)SpringBeanUtil.getBeanByName("serviceBean");    
    }    
    @Override    
    public void run(){    
        if (serviceBean ==null){    
            return;    
        }    
        serviceBean.log();    
        count.addAndGet(1);    
        System.out.println("当前线程为：" + Thread.currentThread().getName() + "count:" + count);    
    }    
    
    public ServiceBean getServiceBean() {    
        return serviceBean;    
    }    
    
    public void setServiceBean(ServiceBean serviceBean) {    
        this.serviceBean = serviceBean;    
    }    
}