Mybatisplus源码分析（待续）

Mybatisplus源码分析

一、自动配置类MybatisPlusAutoConfiguration

  • implements InitializingBean
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@Configuration
@ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class})
@ConditionalOnSingleCandidate(DataSource.class)
//存在单个对象
@EnableConfigurationProperties(MybatisPlusProperties.class)
//开启配置扫描
@AutoConfigureAfter({DataSourceAutoConfiguration.class, MybatisPlusLanguageDriverAutoConfiguration.class})
//自动配置后再加载这些类
public class MybatisPlusAutoConfiguration implements InitializingBean {

实现了InitializingBean，是Spring提供的初始化Bean的一个接口，实现该接口后必须实现afterPropertiesSet()来初始化Bean。

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@Override
//初始化bean
public void afterPropertiesSet() {
    if (!CollectionUtils.isEmpty(mybatisPlusPropertiesCustomizers)) {
        mybatisPlusPropertiesCustomizers.forEach(i -> i.customize(properties));
    }
    checkConfigFileExists();
}
  • 创建SqlSession工厂类对象，对 sqlSessionFactory 进行定义的定义类变为了 MybatisSqlSessionFactoryBean
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@SuppressWarnings("SpringJavaInjectionPointsAutowiringInspection")
@Bean
@ConditionalOnMissingBean
public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
    // TODO 使用 MybatisSqlSessionFactoryBean 而不是 SqlSessionFactoryBean
    MybatisSqlSessionFactoryBean factory = new MybatisSqlSessionFactoryBean();
    factory.setDataSource(dataSource);
    factory.setVfs(SpringBootVFS.class);
    if (StringUtils.hasText(this.properties.getConfigLocation())) {
        factory.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfigLocation()));
    }
    applyConfiguration(factory);
    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 (this.properties.getTypeAliasesSuperType() != null) {
        factory.setTypeAliasesSuperType(this.properties.getTypeAliasesSuperType());
    }
    if (StringUtils.hasLength(this.properties.getTypeHandlersPackage())) {
        factory.setTypeHandlersPackage(this.properties.getTypeHandlersPackage());
    }
    if (!ObjectUtils.isEmpty(this.typeHandlers)) {
        factory.setTypeHandlers(this.typeHandlers);
    }
    Resource[] mapperLocations = this.properties.resolveMapperLocations();
    if (!ObjectUtils.isEmpty(mapperLocations)) {
        factory.setMapperLocations(mapperLocations);
    }
    // TODO 修改源码支持定义 TransactionFactory
    this.getBeanThen(TransactionFactory.class, factory::setTransactionFactory);

    // TODO 对源码做了一定的修改(因为源码适配了老旧的mybatis版本,但我们不需要适配)
    Class<? extends LanguageDriver> defaultLanguageDriver = this.properties.getDefaultScriptingLanguageDriver();
    if (!ObjectUtils.isEmpty(this.languageDrivers)) {
        factory.setScriptingLanguageDrivers(this.languageDrivers);
    }
    Optional.ofNullable(defaultLanguageDriver).ifPresent(factory::setDefaultScriptingLanguageDriver);

    // TODO 自定义枚举包
    if (StringUtils.hasLength(this.properties.getTypeEnumsPackage())) {
        factory.setTypeEnumsPackage(this.properties.getTypeEnumsPackage());
    }
    // TODO 此处必为非 NULL
    GlobalConfig globalConfig = this.properties.getGlobalConfig();
    // TODO 注入填充器
    this.getBeanThen(MetaObjectHandler.class, globalConfig::setMetaObjectHandler);
    // TODO 注入主键生成器
    this.getBeanThen(IKeyGenerator.class, i -> globalConfig.getDbConfig().setKeyGenerator(i));
    // TODO 注入sql注入器
    this.getBeanThen(ISqlInjector.class, globalConfig::setSqlInjector);
    // TODO 注入ID生成器
    this.getBeanThen(IdentifierGenerator.class, globalConfig::setIdentifierGenerator);
    // TODO 设置 GlobalConfig 到 MybatisSqlSessionFactoryBean
    factory.setGlobalConfig(globalConfig);
    return factory.getObject();
}

在 sqlSessionFactory()方法中，除了注入 MyBatis本身的组件，还会注入MyBatis-plus 的 主键生成器、SQL 注入器等组件，最后通过 MybatisSqlSessionFactoryBean#getObject() 方法获取到 sqlSessionFactory 对象。