简介
MyBatis-Plus是一个 MyBatis (opens new window)的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。
一、MyBatis-Plus和SpringBoot整合应用
1.1 项目依赖
在原项目依赖上，加上下面依赖
<dependency>
<groupId></groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.3</version>
</dependency>
1.2 项目配置
使用mybatis-plus-boot-starter后，spring将扫描所有标准@Mapper的类（不需要使用@MapperScan），所以我们直接使用mybatis-plus的功能，不需要手动配置SqlSessionTemplate，MybatisSqlSessionFactoryBean，dataSource，因为MyBatis-Spring-Boot-Starter帮我们配置好了。
mybatis-plus-boot-starter在其文件中配置2个配置类，mybatis-plus主要配置都在MybatisPlusAutoConfiguration中
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二、Mybatis和Spring整合源码分析
其数据源配置和事务都已经配置好了，一般情况下不用我们自己配置
以下代码都在MybatisPlusAutoConfiguration中
2.1 SqlSessionFactory的注册
@Configuration
@ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class})
@ConditionalOnSingleCandidate(DataSource.class)
@EnableConfigurationProperties(MybatisPlusProperties.class)
@AutoConfigureAfter({DataSourceAutoConfiguration.class, MybatisPlusLanguageDriverAutoConfiguration.class})
public class MybatisPlusAutoConfiguration implements InitializingBean {
private static final Logger logger = LoggerFactory.getLogger(MybatisPlusAutoConfiguration.class);
private final MybatisPlusProperties properties;
private final Interceptor[] interceptors;
private final TypeHandler[] typeHandlers;
private final LanguageDriver[] languageDrivers;
private final ResourceLoader resourceLoader;
private final DatabaseIdProvider databaseIdProvider;
private final List<ConfigurationCustomizer> configurationCustomizers;
private final List<MybatisPlusPropertiesCustomizer> mybatisPlusPropertiesCustomizers;
private final ApplicationContext applicationContext;
//构造器注入
public MybatisPlusAutoConfiguration(MybatisPlusProperties properties,
ObjectProvider<Interceptor[]> interceptorsProvider,
ObjectProvider<TypeHandler[]> typeHandlersProvider,
ObjectProvider<LanguageDriver[]> languageDriversProvider,
ResourceLoader resourceLoader,
ObjectProvider<DatabaseIdProvider> databaseIdProvider,
ObjectProvider<List<ConfigurationCustomizer>> configurationCustomizersProvider,
ObjectProvider<List<MybatisPlusPropertiesCustomizer>> mybatisPlusPropertiesCustomizerProvider,
ApplicationContext applicationContext) {
this.properties = properties;
this.interceptors = interceptorsProvider.getIfAvailable();
this.typeHandlers = typeHandlersProvider.getIfAvailable();
this.languageDrivers = languageDriversProvider.getIfAvailable();
this.resourceLoader = resourceLoader;
this.databaseIdProvider = databaseIdProvider.getIfAvailable();
this.configurationCustomizers = configurationCustomizersProvider.getIfAvailable();
this.mybatisPlusPropertiesCustomizers = mybatisPlusPropertiesCustomizerProvider.getIfAvailable();
this.applicationContext = applicationContext;
}
@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());
}
//插件
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
//获取配置文件
if (StringUtils.hasLength(this.properties.getTypeEnumsPackage())) {
factory.setTypeEnumsPackage(this.properties.getTypeEnumsPackage());
}
// TODO 此处必为非 NULL
//获取配置文件
GlobalConfig globalConfig = this.properties.getGlobalConfig();
// TODO 注入填充器 //从容器中找MetaObjectHandler
this.getBeanThen(MetaObjectHandler.class, globalConfig::setMetaObjectHandler);
// TODO 注入主键生成器 //从容器中找IKeyGenerator
this.getBeansThen(IKeyGenerator.class, i -> globalConfig.getDbConfig().setKeyGenerators(i));
// TODO 注入sql注入器 //从容器中找ISqlInjector
this.getBeanThen(ISqlInjector.class, globalConfig::setSqlInjector);
// TODO 注入ID生成器 //从容器中找IdentifierGenerator
this.getBeanThen(IdentifierGenerator.class, globalConfig::setIdentifierGenerator);
// TODO 设置 GlobalConfig 到 MybatisSqlSessionFactoryBean
factory.setGlobalConfig(globalConfig);
return factory.getObject();
}
1、springBoot通过构造器主人会在容器中寻找Interceptor，所以我们可以用以下方式开启分页功能，这和其与springMVC整合有点不同
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
return interceptor;
}
2、springBoot会在容器中寻找MetaObjectHandler类型注入GlobalConfig，所以元对象字段填充控制器对象我们可以交给spring管理，这和其与springMVC整合有点不同
IKeyGenerator,ISqlInjector,IdentifierGenerator 也一样
@Bean
public MyMetaObjectHandler metaObjectHandler() {
return new MyMetaObjectHandler();
}
3、通用枚举，我们通过配置文件指定
mybatis-plus:
# 支持统配符 * 或者 ; 分割
typeEnumsPackage:
4、MyBatis-Plus数据库相关配置，我们通过配置文件指定
mybatis-plus:
global-config:
db-config:
insert-strategy: not_null
update-strategy: not_null
select-strategy: not_null
# 主键类型:
# AUTO(0),数据库ID自增
# NONE(1),未设置主键类型
# INPUT(2),用户输入ID
# ASSIGN_ID(3),全局唯一ID (数字类型唯一ID)
# ASSIGN_UUID(4),全局唯一ID UUID
id-type: INPUT
# 是否开启大写命名，默认不开启
capital-mode: false
logic-delete-field: deleteFlag
logic-delete-value: 1
logic-not-delete-value: 0
2.2 SqlSessionTemplate的注册
@Configuration
@ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class})
@ConditionalOnSingleCandidate(DataSource.class)
@EnableConfigurationProperties(MybatisPlusProperties.class)
@AutoConfigureAfter({DataSourceAutoConfiguration.class, MybatisPlusLanguageDriverAutoConfiguration.class})
public class MybatisPlusAutoConfiguration implements InitializingBean {
@Bean
@ConditionalOnMissingBean
public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
ExecutorType executorType = this.properties.getExecutorType();
if (executorType != null) {
return new SqlSessionTemplate(sqlSessionFactory, executorType);
} else {
return new SqlSessionTemplate(sqlSessionFactory);
}
}
}
与MyBatis和SpringBoot整合的一样
2.3 扫描映射器类
@Configuration
@ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class})
@ConditionalOnSingleCandidate(DataSource.class)
@EnableConfigurationProperties(MybatisPlusProperties.class)
@AutoConfigureAfter({DataSourceAutoConfiguration.class, MybatisPlusLanguageDriverAutoConfiguration.class})
public class MybatisPlusAutoConfiguration implements InitializingBean {
public static class AutoConfiguredMapperScannerRegistrar implements BeanFactoryAware, ImportBeanDefinitionRegistrar {
private BeanFactory beanFactory;
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
if (!AutoConfigurationPackages.has(this.beanFactory)) {
logger.debug("Could not determine auto-configuration package, automatic mapper scanning disabled.");
return;
}
logger.debug("Searching for mappers annotated with @Mapper");
List<String> packages = AutoConfigurationPackages.get(this.beanFactory);
if (logger.isDebugEnabled()) {
packages.forEach(pkg -> logger.debug("Using auto-configuration base package '{}'", pkg));
}
BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(MapperScannerConfigurer.class);
builder.addPropertyValue("processPropertyPlaceHolders", true);
builder.addPropertyValue("annotationClass", Mapper.class);
builder.addPropertyValue("basePackage", StringUtils.collectionToCommaDelimitedString(packages));
BeanWrapper beanWrapper = new BeanWrapperImpl(MapperScannerConfigurer.class);
Set<String> propertyNames = Stream.of(beanWrapper.getPropertyDescriptors()).map(PropertyDescriptor::getName)
.collect(Collectors.toSet());
if (propertyNames.contains("lazyInitialization")) {
// Need to mybatis-spring 2.0.2+
// TODO 兼容了-initialization配置
builder.addPropertyValue("lazyInitialization", "${-initialization:${-initialization:false}}");
}
if (propertyNames.contains("defaultScope")) {
// Need to mybatis-spring 2.0.6+
builder.addPropertyValue("defaultScope", "${-default-scope:}");
}
registry.registerBeanDefinition(MapperScannerConfigurer.class.getName(), builder.getBeanDefinition());
}
@Override
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = beanFactory;
}
}
/**
* If mapper registering configuration or mapper scanning configuration not present, this configuration allow to scan
* mappers based on the same component-scanning path as Spring Boot itself.
*/
@Configuration
@Import(AutoConfiguredMapperScannerRegistrar.class)
@ConditionalOnMissingBean({MapperFactoryBean.class, MapperScannerConfigurer.class})
public static class MapperScannerRegistrarNotFoundConfiguration implements InitializingBean {
@Override
public void afterPropertiesSet() {
logger.debug(
"Not found configuration for registering mapper bean using @MapperScan, MapperFactoryBean and MapperScannerConfigurer.");
}
}
}
与MyBatis和SpringBoot整合的一样