dialect=mysql
下面跟踪SqlSessionFactoryBean.java的源码
public class SqlSessionFactoryBean implements FactoryBean, InitializingBean, ApplicationListener {}
实现了InitializingBean，ApplicationListener，自然而然就会在Spring加载的过程中做一些操作：
public void afterPropertiesSet() throws Exception { Assert.notNull(this.dataSource, "Property 'dataSource' is required"); Assert.notNull(this.sqlSessionFactoryBuilder, "Property 'sqlSessionFactoryBuilder' is required"); Assert.state(this.configuration == null && this.configLocation == null || this.configuration == null || this.configLocation == null, "Property 'configuration' and 'configLocation' can not specified with together"); this.sqlSessionFactory = this.buildSqlSessionFactory(); } this.buildSqlSessionFactory();这个就是核心重点！！！
protected SqlSessionFactory buildSqlSessionFactory() throws IOException { XMLConfigBuilder xmlConfigBuilder = null; Configuration targetConfiguration; if (this.configuration != null) { targetConfiguration = this.configuration; if (targetConfiguration.getVariables() == null) { targetConfiguration.setVariables(this.configurationProperties); } else if (this.configurationProperties != null) { targetConfiguration.getVariables().putAll(this.configurationProperties); } } else if (this.configLocation != null) { xmlConfigBuilder = new XMLConfigBuilder(this.configLocation.getInputStream(), (String)null, this.configurationProperties); targetConfiguration = xmlConfigBuilder.getConfiguration(); } else { LOGGER.debug(() -> { return "Property 'configuration' or 'configLocation' not specified, using default MyBatis Configuration"; }); targetConfiguration = new Configuration(); Optional.ofNullable(this.configurationProperties).ifPresent(targetConfiguration::setVariables); } Optional.ofNullable(this.objectFactory).ifPresent(targetConfiguration::setObjectFactory); Optional.ofNullable(this.objectWrapperFactory).ifPresent(targetConfiguration::setObjectWrapperFactory); Optional.ofNullable(this.vfs).ifPresent(targetConfiguration::setVfsImpl); String[] typeHandlersPackageArray; if (StringUtils.hasLength(this.typeAliasesPackage)) { typeHandlersPackageArray = StringUtils.tokenizeToStringArray(this.typeAliasesPackage, ",; \t\n"); Stream.of(typeHandlersPackageArray).forEach((packageToScan) -> { targetConfiguration.getTypeAliasRegistry().registerAliases(packageToScan, this.typeAliasesSuperType == null ? Object.class : this.typeAliasesSuperType); LOGGER.debug(() -> { return "Scanned package: '" + packageToScan + "' for aliases"; }); }); } if (!ObjectUtils.isEmpty(this.typeAliases)) { Stream.of(this.typeAliases).forEach((typeAlias) -> { targetConfiguration.getTypeAliasRegistry().registerAlias(typeAlias); LOGGER.debug(() -> { return "Registered type alias: '" + typeAlias + "'"; }); }); } if (!ObjectUtils.isEmpty(this.plugins)) { Stream.of(this.plugins).forEach((plugin) -> { targetConfiguration.addInterceptor(plugin); LOGGER.debug(() -> { return "Registered plugin: '" + plugin + "'"; }); }); } if (StringUtils.hasLength(this.typeHandlersPackage)) { typeHandlersPackageArray = StringUtils.tokenizeToStringArray(this.typeHandlersPackage, ",; \t\n"); Stream.of(typeHandlersPackageArray).forEach((packageToScan) -> { targetConfiguration.getTypeHandlerRegistry().register(packageToScan); LOGGER.debug(() -> { return "Scanned package: '" + packageToScan + "' for type handlers"; }); }); } if (!ObjectUtils.isEmpty(this.typeHandlers)) { Stream.of(this.typeHandlers).forEach((typeHandler) -> { targetConfiguration.getTypeHandlerRegistry().register(typeHandler); LOGGER.debug(() -> { return "Registered type handler: '" + typeHandler + "'"; }); }); } if (this.databaseIdProvider != null) { try { targetConfiguration.setDatabaseId(this.databaseIdProvider.getDatabaseId(this.dataSource)); } catch (SQLException var23) { throw new NestedIOException("Failed getting a databaseId", var23); } } Optional.ofNullable(this.cache).ifPresent(targetConfiguration::addCache); if (xmlConfigBuilder != null) { try { xmlConfigBuilder.parse(); LOGGER.debug(() -> { return "Parsed configuration file: '" + this.configLocation + "'"; }); } catch (Exception var21) { throw new NestedIOException("Failed to parse config resource: " + this.configLocation, var21); } finally { ErrorContext.instance().reset(); } } targetConfiguration.setEnvironment(new Environment(this.environment, (TransactionFactory)(this.transactionFactory == null ? new SpringManagedTransactionFactory() : this.transactionFactory), this.dataSource)); if (!ObjectUtils.isEmpty(this.mapperLocations)) { Resource[] var24 = this.mapperLocations; int var4 = var24.length; for(int var5 = 0; var5 < var4; ++var5) { Resource mapperLocation = var24[var5]; if (mapperLocation != null) { try { XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(mapperLocation.getInputStream(), targetConfiguration, mapperLocation.toString(), targetConfiguration.getSqlFragments()); xmlMapperBuilder.parse(); } catch (Exception var19) { throw new NestedIOException("Failed to parse mapping resource: '" + mapperLocation + "'", var19); } finally { ErrorContext.instance().reset(); } LOGGER.debug(() -> { return "Parsed mapper file: '" + mapperLocation + "'"; }); } } } else { LOGGER.debug(() -> { return "Property 'mapperLocations' was not specified or no matching resources found"; }); } return this.sqlSessionFactoryBuilder.build(targetConfiguration); } 这个方法我们慢慢仔细看：
XMLConfigBuilder xmlConfigBuilder = null; Configuration targetConfiguration; if (this.configuration != null) { targetConfiguration = this.configuration; if (targetConfiguration.getVariables() == null) { targetConfiguration.setVariables(this.configurationProperties); } else if (this.configurationProperties != null) { targetConfiguration.getVariables().putAll(this.configurationProperties); } } else if (this.configLocation != null) { xmlConfigBuilder = new XMLConfigBuilder(this.configLocation.getInputStream(), (String)null, this.configurationProperties); targetConfiguration = xmlConfigBuilder.getConfiguration(); } else { LOGGER.debug(() -> { return "Property 'configuration' or 'configLocation' not specified, using default MyBatis Configuration"; }); targetConfiguration = new Configuration(); Optional.ofNullable(this.configurationProperties).ifPresent(targetConfiguration::setVariables); } 上面中标红的就是核心代码，
public XMLConfigBuilder(InputStream inputStream, String environment, Properties props) { this(new XPathParser(inputStream, true, props, new XMLMapperEntityResolver()), environment, props); } public XPathParser(InputStream inputStream, boolean validation, Properties variables, EntityResolver entityResolver) { commonConstructor(validation, variables, entityResolver); this.document = createDocument(new InputSource(inputStream)); } private Document createDocument(InputSource inputSource) { // important: this must only be called AFTER common constructor try { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); factory.setValidating(validation); factory.setNamespaceAware(false); factory.setIgnoringComments(true); factory.setIgnoringElementContentWhitespace(false); factory.setCoalescing(false); factory.setExpandEntityReferences(true); DocumentBuilder builder = factory.newDocumentBuilder(); builder.setEntityResolver(entityResolver); builder.setErrorHandler(new ErrorHandler() { @Override public void error(SAXParseException exception) throws SAXException { throw exception; } @Override public void fatalError(SAXParseException exception) throws SAXException { throw exception; } @Override public void warning(SAXParseException exception) throws SAXException { } }); return builder.parse(inputSource); } catch (Exception e) { throw new BuilderException("Error creating document instance. Cause: " + e, e); } } public Document parse(InputSource is) throws SAXException, IOException { if (is == null) { throw new IllegalArgumentException( DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN, "jaxp-null-input-source", null)); } if (fSchemaValidator != null) { if (fSchemaValidationManager != null) { fSchemaValidationManager.reset(); fUnparsedEntityHandler.reset(); } resetSchemaValidator(); } domParser.parse(is); Document doc = domParser.getDocument(); domParser.dropDocumentReferences(); return doc; } configLocation就算解析完成了；其他的
typeAliasesPackage，plugins都没什么好看的，不过
plugins中通过添加interceptor完成插件的拦截入口，常用的就是PageHelper分页插件，后面可以具体看看这个是如何生效的！！
if (!ObjectUtils.isEmpty(this.plugins)) { Stream.of(this.plugins).forEach((plugin) -> { targetConfiguration.addInterceptor(plugin); LOGGER.debug(() -> { return "Registered plugin: '" + plugin + "'"; }); }); } ！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
protected final MapperRegistry mapperRegistry = new MapperRegistry(this);
public class Configuration { protected Environment environment; protected boolean safeRowBoundsEnabled = false; protected boolean safeResultHandlerEnabled = true; protected boolean mapUnderscoreToCamelCase = false; protected boolean aggressiveLazyLoading = true; protected boolean multipleResultSetsEnabled = true; protected boolean useGeneratedKeys = false; protected boolean useColumnLabel = true; protected boolean cacheEnabled = true; protected boolean callSettersOnNulls = false; protected boolean useActualParamName = true; protected String logPrefix; protected Class logImpl; protected Class vfsImpl; protected LocalCacheScope localCacheScope = LocalCacheScope.SESSION; protected JdbcType jdbcTypeForNull = JdbcType.OTHER; protected Set lazyLoadTriggerMethods = new HashSet (Arrays.asList(new String[] { "equals", "clone", "hashCode", "toString" })); protected Integer defaultStatementTimeout; protected Integer defaultFetchSize; protected ExecutorType defaultExecutorType = ExecutorType.SIMPLE; protected AutoMappingBehavior autoMappingBehavior = AutoMappingBehavior.PARTIAL; protected AutoMappingUnknownColumnBehavior autoMappingUnknownColumnBehavior = AutoMappingUnknownColumnBehavior.NONE; protected Properties variables = new Properties(); protected ReflectorFactory reflectorFactory = new DefaultReflectorFactory(); protected ObjectFactory objectFactory = new DefaultObjectFactory(); protected ObjectWrapperFactory objectWrapperFactory = new DefaultObjectWrapperFactory(); protected boolean lazyLoadingEnabled = false; protected ProxyFactory proxyFactory = new JavassistProxyFactory(); // #224 Using internal Javassist instead of OGNL protected String databaseId; /** * Configuration factory class. * Used to create Configuration for loading deserialized unread properties. * * @see Issue 300 (google code) */ protected Class configurationFactory; protected final MapperRegistry mapperRegistry = new MapperRegistry(this); protected final InterceptorChain interceptorChain = new InterceptorChain(); protected final TypeHandlerRegistry typeHandlerRegistry = new TypeHandlerRegistry(); protected final TypeAliasRegistry typeAliasRegistry = new TypeAliasRegistry(); protected final LanguageDriverRegistry languageRegistry = new LanguageDriverRegistry(); protected final Map mappedStatements = new StrictMap ("Mapped Statements collection"); protected final Map caches = new StrictMap ("Caches collection"); protected final Map resultMaps = new StrictMap ("Result Maps collection"); protected final Map parameterMaps = new StrictMap ("Parameter Maps collection"); protected final Map keyGenerators = new StrictMap ("Key Generators collection"); protected final Set loadedResources = new HashSet (); protected final Map sqlFragments = new StrictMap ("XML fragments parsed from previous mappers"); protected final Collection incompleteStatements = new LinkedList (); protected final Collection incompleteCacheRefs = new LinkedList (); protected final Collection incompleteResultMaps = new LinkedList (); protected final Collection incompleteMethods = new LinkedList (); /* * A map holds cache-ref relationship. The key is the namespace that * references a cache bound to another namespace and the value is the * namespace which the actual cache is bound to. */ protected final Map cacheRefMap = new HashMap (); public Configuration(Environment environment) { this(); this.environment = environment; } public Configuration() { typeAliasRegistry.registerAlias("JDBC", JdbcTransactionFactory.class); typeAliasRegistry.registerAlias("MANAGED", ManagedTransactionFactory.class); typeAliasRegistry.registerAlias("JNDI", JndiDataSourceFactory.class); typeAliasRegistry.registerAlias("POOLED", PooledDataSourceFactory.class); typeAliasRegistry.registerAlias("UNPOOLED", UnpooledDataSourceFactory.class); typeAliasRegistry.registerAlias("PERPETUAL", PerpetualCache.class); typeAliasRegistry.registerAlias("FIFO", FifoCache.class); typeAliasRegistry.registerAlias("LRU", LruCache.class); typeAliasRegistry.registerAlias("SOFT", SoftCache.class); typeAliasRegistry.registerAlias("WEAK", WeakCache.class); typeAliasRegistry.registerAlias("DB_VENDOR", VendorDatabaseIdProvider.class); typeAliasRegistry.registerAlias("XML", XMLLanguageDriver.class); typeAliasRegistry.registerAlias("RAW", RawLanguageDriver.class); typeAliasRegistry.registerAlias("SLF4J", Slf4jImpl.class); typeAliasRegistry.registerAlias("COMMONS_LOGGING", JakartaCommonsLoggingImpl.class); typeAliasRegistry.registerAlias("LOG4J", Log4jImpl.class); typeAliasRegistry.registerAlias("LOG4J2", Log4j2Impl.class); typeAliasRegistry.registerAlias("JDK_LOGGING", Jdk14LoggingImpl.class); typeAliasRegistry.registerAlias("STDOUT_LOGGING", StdOutImpl.class); typeAliasRegistry.registerAlias("NO_LOGGING", NoLoggingImpl.class); typeAliasRegistry.registerAlias("CGLIB", CglibProxyFactory.class); typeAliasRegistry.registerAlias("JAVASSIST", JavassistProxyFactory.class); languageRegistry.setDefaultDriverClass(XMLLanguageDriver.class); languageRegistry.register(RawLanguageDriver.class); }