某些時候，某些類是不歸IOC管的，如我們的一些Util，如何使用IOC中的Bean？

1、寫一個SpringUtil類，該類用於操縱Spring的ApplicationContext

@Component的註解是需要的，該Util是要被Spring管理的。

@Component
public class SpringUtil implements ApplicationContextAware
{
    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws
 
 BeansException
    {
        if (SpringUtil.applicationContext == null)
        {
            SpringUtil.applicationContext = applicationContext;
        }
    }

    public static ApplicationContext getApplicationContext()
    {
        return applicationContext;
    }

    public static Object getBean(String name)
    {
        
 
return getApplicationContext().getBean(name);
    }

    public static <T> T getBean(Class<T> clazz)
    {
        return getApplicationContext().getBean(clazz);
    }

    public static <T> T getBean(String name, Class<T> clazz)
    {
        return getApplicationContext().getBean(name, clazz);
    }
}
 

2、通過@Bean註解，返回一個Bean；

@Component
@Transactional
public class SysParamBusiness
{
    @Autowired
    private SysParamDao sysParamDao;
    
    public void modify(SysParamMO mo) throws LittleCatException
    {
        sysParamDao.modify(mo);
    }
    public String getValueByName(String name) throws LittleCatException
    {
        return sysParamDao.getValueByName(name).getValue();
    }
    public List<SysParamMO> getList() throws LittleCatException
    {
        return sysParamDao.getList();
    }
    
    @Bean(name="SysParamBusiness") 
    public SysParamBusiness getSysParamBusiness()
    {
        return new SysParamBusiness();
    }
}

3、在我們自己的Util中使用

public class SysParamUtil
{
    public static String PARAM_NAME_MEMBER_ENABLE_DAYS = "member_enable_days";
    
    private static final SysParamBusiness sysParamBusiness = (SysParamBusiness) SpringUtil.getBean("SysParamBusiness");

    public static String getValueByName(String name) throws LittleCatException
    {
        return sysParamBusiness.getValueByName(name);
    }
}

註：

也可以這樣使用（如果沒有特殊邏輯，推薦使用這種方法）：

private static final SysParamBusiness sysParamBusiness = SpringUtil.getBean(SysParamBusiness.class);

這樣，第二步就可以省略了。

【SpringBoot】在IOC之外的類中使用IOC內部的Bean