前言
场景:将一些公共的方法封装成了一个jar包,在其他项目中进行引用的时候报错
报错原因:bean没有注入,引进来的jar包没有被spring管理,因为类没有被@Service,@Repository等类注解,如果我们想用@Autowired注入也会报错
示例:
@Autowired public UserService userService;
报错:
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException:
No qualifying bean of type [com.lib.user.UserService] found for dependency:
expected at least 1 bean which qualifies as autowire candidate for this dependency.
Dependency annotations:
{@javax.annotation.Resource(shareable=true, lookup=, name=, description=, authenticationType=CONTAINER, type=class java.lang.Object, mappedName=)}
解决方式(1)
创建配置类使用@Bean注解进行注入类。
@Configuration public class UserServiceConfig { @Bean UserService getUserService(){ UserService userService = new UserService(); return userService; } }
解决方式(2)
在启动类加上扫描注解@ComponentScan("/")
//手动加上@ComponentScan注解并指定那个bean所在的包 //@ComponentScan 的作用就是根据定义的扫描路径,把符合扫描规则的类装配到spring容器中 @ComponentScan(basePackages={"com.util.user"}) @SpringBootApplication public class UserApplication { public static void main(String[] args) { SpringApplication.run(UserApplication .class, args); } }