attempted to return null from a method with a primitive return type (int)

我在使用springboot做登录查询的时候报错了,我输入的是数据库中不存在的用户名与密码,返回值应该是null;

把返回值类型改成Integer

attempted to return null from a method with a primitive return type (int)

我来运行看看,是否真的有效

还是报错!

网上说把dao service返回值都改成Integer

attempted to return null from a method with a primitive return type (int)

然后再control层里面

也是Integer接受值，这样写

attempted to return null from a method with a primitive return type (int)

终于不报错了！太坎坷了！