mybatis配置的时候需要注意一下几点:
- 当yml中配置了config-location的时候,java代码配置的配置将不再生效
- 当mybatis.config-location=classpath:config/config.xml
mybatis.configuration.map-underscore-to-camel-case=true
config-location和configuration.**的配置不能共存
换而言之, yml、xml、java都能进行配置
yml、xml的优先级高于java代码 ==== 符合了spring的设计,配置大于编码
yml和xml不能共存
ConfigurationCustomizer.class
public interface ConfigurationCustomizer {
void customize(Configuration var1);
}
MybatisAutoConfiguration.class
@Configuration//配置类
//SqlSessionFactory、SqlSessionFactoryBean存在的时候配置生效
@ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class})
//DataSource类存在时生效
@ConditionalOnBean({DataSource.class})
//启用配置属性MybatisProperties类
@EnableConfigurationProperties({MybatisProperties.class})
//在DataSourceAutoConfiguration配置之后配置
@AutoConfigureAfter({DataSourceAutoConfiguration.class})
public class MybatisAutoConfiguration {
//日志
private static final Logger logger = LoggerFactory.getLogger(MybatisAutoConfiguration.class);
//配置类
private final MybatisProperties properties;
private final Interceptor[] interceptors;
//资源加载器
private final ResourceLoader resourceLoader;
private final DatabaseIdProvider databaseIdProvider;
//重点:放置接口进行配置的list
private final List<ConfigurationCustomizer> configurationCustomizers;
public MybatisAutoConfiguration(MybatisProperties properties, ObjectProvider<Interceptor[]> interceptorsProvider, ResourceLoader resourceLoader, ObjectProvider<DatabaseIdProvider> databaseIdProvider, ObjectProvider<List<ConfigurationCustomizer>> configurationCustomizersProvider) {
this.properties = properties;
this.interceptors = (Interceptor[])interceptorsProvider.getIfAvailable();
this.resourceLoader = resourceLoader;
this.databaseIdProvider = (DatabaseIdProvider)databaseIdProvider.getIfAvailable();
//拿到当前工程下边所有申明@bean的ConfigurationCustomizer的实例
this.configurationCustomizers = (List)configurationCustomizersProvider.getIfAvailable();
}
//构造行数执行之后进行检查
@PostConstruct
public void checkConfigFileExists() {
if (this.properties.isCheckConfigLocation() && StringUtils.hasText(this.properties.getConfigLocation())) {
Resource resource = this.resourceLoader.getResource(this.properties.getConfigLocation());
Assert.state(resource.exists(), "Cannot find config location: " + resource + " (please add config file or check your Mybatis configuration)");
}
}
@Bean
@ConditionalOnMissingBean
public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
factory.setDataSource(dataSource);
factory.setVfs(SpringBootVFS.class);
//获取mybatis.config-location=classpath:config/config.xml配置
if (StringUtils.hasText(this.properties.getConfigLocation())) {
factory.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfigLocation()));
}
//此处永远为空
org.apache.ibatis.session.Configuration configuration = this.properties.getConfiguration();
//在yml不存在config-location属性是创建configuration
if (configuration == null && !StringUtils.hasText(this.properties.getConfigLocation())) {
configuration = new org.apache.ibatis.session.Configuration();
}
//生效java代码的配置
if (configuration != null && !CollectionUtils.isEmpty(this.configurationCustomizers)) {
Iterator var4 = this.configurationCustomizers.iterator();
while(var4.hasNext()) {
//迭代拿到申明@bean接口的实例
ConfigurationCustomizer customizer = (ConfigurationCustomizer)var4.next();
customizer.customize(configuration);
}
}
factory.setConfiguration(configuration);
if (this.properties.getConfigurationProperties() != null) {
factory.setConfigurationProperties(this.properties.getConfigurationProperties());
}
if (!ObjectUtils.isEmpty(this.interceptors)) {
factory.setPlugins(this.interceptors);
}
if (this.databaseIdProvider != null) {
factory.setDatabaseIdProvider(this.databaseIdProvider);
}
if (StringUtils.hasLength(this.properties.getTypeAliasesPackage())) {
factory.setTypeAliasesPackage(this.properties.getTypeAliasesPackage());
}
if (StringUtils.hasLength(this.properties.getTypeHandlersPackage())) {
factory.setTypeHandlersPackage(this.properties.getTypeHandlersPackage());
}
//设置mybatis的mapper xml
if (!ObjectUtils.isEmpty(this.properties.resolveMapperLocations())) {
factory.setMapperLocations(this.properties.resolveMapperLocations());
}
return factory.getObject();
}
}
MybatisProperties .class
@ConfigurationProperties(
prefix = "mybatis"
)
//一堆get set方法
public class MybatisProperties {
public static final String MYBATIS_PREFIX = "mybatis";
private String configLocation;
private String[] mapperLocations;
private String typeAliasesPackage;
private String typeHandlersPackage;
private boolean checkConfigLocation = false;
private ExecutorType executorType;
private Properties configurationProperties;
@NestedConfigurationProperty//这个注解相当于把Configuration类里的属性 嵌套进来了
private Configuration configuration;
}