Configuration类的@Value属性值为null

Posted 2021-03-24 baby123

今天写的Configuration类的@Value属性值为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，详情请查阅官方文档
        Properties properties = new Properties();
        properties.setProperty("mappers", MAPPER_INTERFACE_REFERENCE);
        properties.setProperty("notEmpty", "false");//insert、update是否判断字符串类型!=‘‘ 即 test="str != null"表达式内是否追加 and str != ‘‘
        properties.setProperty("IDENTITY", "mysql");
        mapperScannerConfigurer.setProperties(properties);

        return mapperScannerConfigurer;
    }

}

问题的原因：

　　MapperScannerConfigurer实现了BeanDefinitionRegistryPostProcessor使得spring容器的执行的一些顺序问题，引起了上述@Value属性不能注入

解决方法：

　　将MapperScannerConfigurer单独放在一个@Configuration类下