javaresource注解，关于@Resource注解使⽤的注意事项@Resource是Java⾃带的@interface类型，类似于Spring的@Autowired。但是两者的注⼊⽅式有很⼤的区别。@Resource是通过name注⼊，@Autowired是通过type注⼊，这也是这次刨坑的主要原因。
场景还原
背景介绍
⼀个类SettingService加了@Service，name为settingService(spring扫描⾃动命名机制-将类的⾸字母⼩写当做name)
另⼀个类BallGameSettingService也加了@Service，name为ballGameSettingService
代码如下：
@Service
public class SettingService {
......
}
@Service
public class BallGameSettingService{
.......
}
导⽕线
以下注⼊将会出现异常：Error creating bean with name ‘ballGameSettingController’: Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named
‘settingService’ is expected to be of type ‘BallGameSettingService’ but was actually of type
‘SettingService…4ce4a19’
public class BallGameSettingController extends BaseController {
@Resource
private BallGameSettingService settingService;
......
}
将上⾯的代码换成以下三种写法都可以：
public class BallGameSettingController extends BaseController {
@Resource(name = "ballGameSettingService")
private BallGameSettingService settingService;
......
}
或者
public class BallGameSettingController extends BaseController {
@Resource
private BallGameSettingService ballGameSettingService;
......
}
或者
public class BallGameSettingController extends BaseController {
@Autowired
private BallGameSettingService settingService;
......
}
根本原因：@Resource是通过name注⼊，@Autowired是通过type注⼊
在使⽤@Resource时，如果没有设置name，也就是 @Resource(name = “ballGameSettingService”) 时，会默认取变量名称当做name。所以造成这次异常的原因：
我们环境中存在两个@Service的bean，名字分别为：settingService和ballGameSettingService，我们在通过以下代码注⼊的时候，获取到的是settingService(类型：SettingService)，导致了类型出错。
@Resource
private BallGameSettingService settingService;
以下两种正确写法的本质是⼀样，就是获取ballGameSettingService(类型：BallGameSettingService)
public class BallGameSettingController extends BaseController {
@Resource(name = "ballGameSettingService")
private BallGameSettingService settingService;
......
resource和autowired注解的区别
}
和
public class BallGameSettingController extends BaseController {
@Resource
private BallGameSettingService ballGameSettingService;
......
}
使⽤@Autowired的本质是通过BallGameSettingService类型去获取

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。