spring的注解开发 Cannot load configuration class

Question

运行UserController的时候报错

public class UserController {
    public static void main(String[] args) {
       // ApplicationContext app=new ClassPathXmlApplicationContext("applicationContext.xml");
        ApplicationContext app=new AnnotationConfigApplicationContext(SpringConfiguration.class);
        UserService userService=(UserService) app.getBean("dataSource");
        userService.save();
    }
}

@ComponentScan("com")
@PropertySource("classpath:jdbc.properties")  //用于指定properties文件的配置
public class DataSourceConfiguration {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String user;
    @Value("${jdbc.password}")
    private String password;
    @Bean("dataSource")//把当前方法的返回值作为bean对象存入spring的ioc容器中(以指定名称)
    public DataSource getDateSource() throws PropertyVetoException {
        ComboPooledDataSource dateSource=new ComboPooledDataSource();
        dateSource.setDriverClass(driver);
        dateSource.setJdbcUrl(url);
        dateSource.setUser(user);
        dateSource.setPassword(password);
        return dateSource;
    }
}

@Configuration
//组件扫描
@ComponentScan("com.itheima")
@Import({DataSourceConfiguration.class})
public class SpringConfiguration {

}

Exception in thread "main" java.lang.IllegalStateException: Cannot load configuration class: com.itheima.config.SpringConfiguration
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.enhanceConfigurationClasses(ConfigurationClassPostProcessor.java:414)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanFactory(ConfigurationClassPostProcessor.java:254)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:284)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:128)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:694)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532)
    at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:88)
    at com.itheima.web.UserController.main(UserController.java:13)
Caused by: java.lang.ExceptionInInitializerError

Answer 1

你只是注入了DataSource的bean对象，并没有注入UserService，所以你获取的是DataSource.
DataSource dataSource=(DataSource) app.getBean("dataSource");
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