spring mybatis之sqlSessionFactoryBean

sqlSessionFactoryBean实现了InitializingBean和FactoryBean

1.FactoryBean 实现了FactoryBean的类，通过getBean方法获取bean时,就是调用getObject()返回实例

2.InitializingBean 实现了InitializingBean的bean会在初始化时调用其afterPropertiesSet方法来进行bean的逻辑初始化

public void afterPropertiesSet() throws Exception {
notNull(dataSource, "Property 'dataSource' is required");
notNull(sqlSessionFactoryBuilder, "Property 'sqlSessionFactoryBuilder' is required");

this.sqlSessionFactory = buildSqlSessionFactory();
}

buildSqlSessionFactory

<bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="mapperLocations" value="classpath*:mybatis/mapper/**/*.xml" />
<property name="typeAliasesPackage" value="com.eroadsf.springdemo.mybatis.entity" />
</bean>

protected SqlSessionFactory buildSqlSessionFactory() throws IOException {

Configuration configuration;

XMLConfigBuilder xmlConfigBuilder = null;
if (this.configLocation != null) {
xmlConfigBuilder = new XMLConfigBuilder(this.configLocation.getInputStream(), null, this.configurationProperties);
configuration = xmlConfigBuilder.getConfiguration();
} else {
if (logger.isDebugEnabled()) {
logger.debug("Property 'configLocation' not specified, using default MyBatis Configuration");
}
configuration = new Configuration();
configuration.setVariables(this.configurationProperties);
}

if (this.objectFactory != null) {
configuration.setObjectFactory(this.objectFactory);
}

if (this.objectWrapperFactory != null) {
configuration.setObjectWrapperFactory(this.objectWrapperFactory);
}
//typeAliasesPackage
if (hasLength(this.typeAliasesPackage)) {
String[] typeAliasPackageArray = tokenizeToStringArray(this.typeAliasesPackage,
ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
for (String packageToScan : typeAliasPackageArray) {
configuration.getTypeAliasRegistry().registerAliases(packageToScan,
typeAliasesSuperType == null ? Object.class : typeAliasesSuperType);
if (logger.isDebugEnabled()) {
logger.debug("Scanned package: '" + packageToScan + "' for aliases");
}
}
}
//typeAliases
if (!isEmpty(this.typeAliases)) {
for (Class<?> typeAlias : this.typeAliases) {
configuration.getTypeAliasRegistry().registerAlias(typeAlias);
if (logger.isDebugEnabled()) {
logger.debug("Registered type alias: '" + typeAlias + "'");
}
}
}
//plugins
if (!isEmpty(this.plugins)) {
for (Interceptor plugin : this.plugins) {
configuration.addInterceptor(plugin);
if (logger.isDebugEnabled()) {
logger.debug("Registered plugin: '" + plugin + "'");
}
}
}
//typeHandlersPackage
if (hasLength(this.typeHandlersPackage)) {
String[] typeHandlersPackageArray = tokenizeToStringArray(this.typeHandlersPackage,
ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
for (String packageToScan : typeHandlersPackageArray) {
configuration.getTypeHandlerRegistry().register(packageToScan);
if (logger.isDebugEnabled()) {
logger.debug("Scanned package: '" + packageToScan + "' for type handlers");
}
}
}
//typeHandlers
if (!isEmpty(this.typeHandlers)) {
for (TypeHandler<?> typeHandler : this.typeHandlers) {
configuration.getTypeHandlerRegistry().register(typeHandler);
if (logger.isDebugEnabled()) {
logger.debug("Registered type handler: '" + typeHandler + "'");
}
}
}

if (xmlConfigBuilder != null) {
try {
xmlConfigBuilder.parse();

if (logger.isDebugEnabled()) {
logger.debug("Parsed configuration file: '" + this.configLocation + "'");
}
} catch (Exception ex) {
throw new NestedIOException("Failed to parse config resource: " + this.configLocation, ex);
} finally {
ErrorContext.instance().reset();
}
}
//transactionFactory
if (this.transactionFactory == null) {
this.transactionFactory = new SpringManagedTransactionFactory();
}

Environment environment = new Environment(this.environment, this.transactionFactory, this.dataSource);
configuration.setEnvironment(environment);
//databaseIdProvider
if (this.databaseIdProvider != null) {
try {
configuration.setDatabaseId(this.databaseIdProvider.getDatabaseId(this.dataSource));
} catch (SQLException e) {
throw new NestedIOException("Failed getting a databaseId", e);
}
}
//mapperLocations
if (!isEmpty(this.mapperLocations)) {
for (Resource mapperLocation : this.mapperLocations) {
if (mapperLocation == null) {
continue;
}

try {
XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(mapperLocation.getInputStream(),
configuration, mapperLocation.toString(), configuration.getSqlFragments());
xmlMapperBuilder.parse();
} catch (Exception e) {
throw new NestedIOException("Failed to parse mapping resource: '" + mapperLocation + "'", e);
} finally {
ErrorContext.instance().reset();
}

if (logger.isDebugEnabled()) {
logger.debug("Parsed mapper file: '" + mapperLocation + "'");
}
}
} else {
if (logger.isDebugEnabled()) {
logger.debug("Property 'mapperLocations' was not specified or no matching resources found");
}
}

return this.sqlSessionFactoryBuilder.build(configuration);
}

根据configLocation构造xmlConfigBuilder并进行解析，spring还整合了mybatis中其他属性的注入，并通过configuration来作为载体获取配置信息最终使用sqlSessionFactoryBuilder.build(configuration)得到sqlSessionFactory实例

2.getObject() 方法

public SqlSessionFactory getObject() throws Exception {
if (this.sqlSessionFactory == null) {
afterPropertiesSet();
}

return this.sqlSessionFactory;
}