springboot 2 配置文件

自动配置原理解析

@SpringBootApplication
public class SpringbootdemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringbootdemoApplication.class, args);
    }
}

从java类的入口进入 ，点击最后会出现（AutoConfigurationImportSelector中）

    protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
        List<String> configurations = SpringFactoriesLoader.loadFactoryNames(this.getSpringFactoriesLoaderFactoryClass(), this.getBeanClassLoader());
        Assert.notEmpty(configurations, "No auto configuration classes found in META-INF/spring.factories. If you are using a custom packaging, make sure that file is correct.");
        return configurations;
    }

SpringFactoriesLoader.loadFactoryNames 方法的作用就是从META-INF/spring.factories文件中读取指定 类对应的类名称列表

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.mybatis.spring.boot.autoconfigure.MybatisLanguageDriverAutoConfiguration,\
org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration

这些类就是存有自动配置信息的类，而 SpringApplication在获取这些类名后再加载

选取一个MybatisAutoConfiguration分析 @EnableConfigurationProperties({MybatisProperties.class})代表加载MybatisProperties服务器配置属性类

@Configuration
@ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class})
@ConditionalOnSingleCandidate(DataSource.class)
@EnableConfigurationProperties({MybatisProperties.class})
@AutoConfigureAfter({DataSourceAutoConfiguration.class, MybatisLanguageDriverAutoConfiguration.class})
public class MybatisAutoConfiguration implements InitializingBean {
    private static final Logger logger = LoggerFactory.getLogger(MybatisAutoConfiguration.class);
    private final MybatisProperties properties;
    private final Interceptor[] interceptors;
    private final TypeHandler[] typeHandlers;
    private final LanguageDriver[] languageDrivers

进入MybatisProperties类

@ConfigurationProperties(
    prefix = "mybatis"
)
public class MybatisProperties {
    public static final String MYBATIS_PREFIX = "mybatis";
    private static final ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
    private String configLocation;
    private String[] mapperLocations;
    private String typeAliasesPackage;

mapperLocations写入的配置为
单词用 - 隔开

mybatis.mapper-locations=classpath:mapper/*Mapper.xml

所以我们写在这里的文件，就会被springboot加载出来

配置文件

类型之前讲解过 常用的配置地址添加链接描述