Configuration類的@Value屬性值為null

今天寫的Configuration類的@Value屬性值為null

@Configuration
public class MybatisConfigurer {
    @Value("${spring.datasource.url}")
    private String dbUrl;
    @Value("${spring.datasource.username}")
    private String username;
    @Value("${spring.datasource.password}")
    private String password;
    @Value("${spring.datasource.driver-class-name}")
    private String driverClassName;
    ……
    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer() {
        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
        mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactoryBean");
        mapperScannerConfigurer.setBasePackage("com.abc.devide.demo.mapper");
        //配置通用Mapper，詳情請查閱官方文檔
        Properties properties = new Properties();
        properties.setProperty("mappers", MAPPER_INTERFACE_REFERENCE);
        properties.setProperty("notEmpty", "false");//insert、update是否判斷字符串類型!='' 即 test="str != null"表達式內是否追加 and str != ''
        properties.setProperty("IDENTITY", "MYSQL");
        mapperScannerConfigurer.setProperties(properties);

        return mapperScannerConfigurer;
    }

}

問題的原因：

　　MapperScannerConfigurer實現了BeanDefinitionRegistryPostProcessor使得spring容器的執行的一些順序問題，引起了上述@Value屬性不能注入

解決方法：

　　將MapperScannerConfigurer單獨放在一個@Configuration類下