1.入口

    public static void main(String[] args) {//获取配置文件信息流InputStream stream = Demo.class.getClassLoader().getResourceAsStream("mybatis.xml");//使用SqlSessionFactory构建器，读取配置文件构建出一个sessionFactorySqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(stream);//通过sessionFactory开启一个SessionSqlSession sqlSession = sessionFactory.openSession(true);//调用selectOne方法查询数据User user = sqlSession.selectOne("org.demo.bean.UserMapper.getUser", 1);//输出System.out.println(user);}

2.使用SqlSessionFactory构建器，读取配置文件构建出一个sessionFactory

  /*** 读取配置文件流 构建一个* @param inputStream 配置文件流*/public SqlSessionFactory build(InputStream inputStream) {return build(inputStream, null, null);}public SqlSessionFactory build(InputStream inputStream, String environment, Properties properties) {try {//1.根据配置文件信息流，生成一个XMLConfigBuilderXMLConfigBuilder parser = new XMLConfigBuilder(inputStream, environment, properties);//2.构建SqlSessionFactory并返回return build(parser.parse());} catch (Exception e) {throw ExceptionFactory.wrapException("Error building SqlSession.", e);} finally {ErrorContext.instance().reset();try {inputStream.close();} catch (IOException e) {}}}

2.1 XMLConfigBuilder的创建

  /*** 构建XMLConfigBuilder对象*/public XMLConfigBuilder(InputStream inputStream, String environment, Properties props) {this(new XPathParser(inputStream, true, props, new XMLMapperEntityResolver()), environment, props);}private XMLConfigBuilder(XPathParser parser, String environment, Properties props) {//创建一个Configuration并调用父类构造方法进行赋值super(new Configuration());ErrorContext.instance().resource("SQL Mapper Configuration");this.configuration.setVariables(props);this.parsed = false;this.environment = environment;this.parser = parser;}

其中XPathParser对象构造函数如下

  /*** 构建XPathParser对象*/public XPathParser(InputStream inputStream, boolean validation, Properties variables, EntityResolver entityResolver) {//1.赋值commonConstructor(validation, variables, entityResolver);//2.读取配置文件信息流构建document 并记录到XPathParser对象中this.document = createDocument(new InputSource(inputStream));}/*** 赋值*/private void commonConstructor(boolean validation, Properties variables, EntityResolver entityResolver) {this.validation = validation;this.entityResolver = entityResolver;this.variables = variables;XPathFactory factory = XPathFactory.newInstance();this.xpath = factory.newXPath();}

这里将配置文件构建成一个document对象赋值到XPathParser对象的XPathParser中

2.构建SqlSessionFactory

  public SqlSessionFactory build(InputStream inputStream, String environment, Properties properties) {try {//1.根据配置文件信息流，生成一个XMLConfigBuilderXMLConfigBuilder parser = new XMLConfigBuilder(inputStream, environment, properties);//2.根据parser构建SqlSessionFactory并返回return build(parser.parse());} catch (Exception e) {throw ExceptionFactory.wrapException("Error building SqlSession.", e);} finally {ErrorContext.instance().reset();try {inputStream.close();} catch (IOException e) {}}}public SqlSessionFactory build(Configuration config) {return new DefaultSqlSessionFactory(config);}

这里是直接根据Configuration创建一个DefaultSqlSessionFactory对象进行返回。这里我们看一下Configuration对象的形成是再parser.parse()方法返回的。

  public Configuration parse() {//用parsed保证方法只会执行一次 if (parsed) {throw new BuilderException("Each XMLConfigBuilder can only be used once.");}parsed = true; //修改为true  不会多次执行//parseConfiguration(parser.evalNode("/configuration"));return configuration;}private void parseConfiguration(XNode root) {try {propertiesElement(root.evalNode("properties"));Properties settings = settingsAsProperties(root.evalNode("settings"));loadCustomVfs(settings);loadCustomLogImpl(settings);typeAliasesElement(root.evalNode("typeAliases"));pluginElement(root.evalNode("plugins"));objectFactoryElement(root.evalNode("objectFactory"));objectWrapperFactoryElement(root.evalNode("objectWrapperFactory"));reflectorFactoryElement(root.evalNode("reflectorFactory"));settingsElement(settings);//解析environments节点信息environmentsElement(root.evalNode("environments"));databaseIdProviderElement(root.evalNode("databaseIdProvider"));typeHandlerElement(root.evalNode("typeHandlers"));//解析mapper节点信息mapperElement(root.evalNode("mappers"));} catch (Exception e) {throw new BuilderException("Error parsing SQL Mapper Configuration. Cause: " + e, e);}}

由上可知，parse方法只会执行一次，parseConfiguration是读取配置文件中的各个节点信息，根据节点信息进行处理，这些节点读取的顺序是不可以改变的。

2.1 environmentsElement节点信息解析

  /*** 解析environments节点信息*/private void environmentsElement(XNode context) throws Exception {if (context != null) {if (environment == null) {environment = context.getStringAttribute("default");}for (XNode child : context.getChildren()) {String id = child.getStringAttribute("id");if (isSpecifiedEnvironment(id)) {TransactionFactory txFactory = transactionManagerElement(child.evalNode("transactionManager"));//解析dataSource节点 生成DataSourceFactoryDataSourceFactory dsFactory = dataSourceElement(child.evalNode("dataSource"));//构建数据源DataSourceDataSource dataSource = dsFactory.getDataSource();//创建Environment.Builder构建器并设置txFactory与dataSource的信息Environment.Builder environmentBuilder = new Environment.Builder(id).transactionFactory(txFactory).dataSource(dataSource);//利用构建器构建一个Environment设置到configuration中configuration.setEnvironment(environmentBuilder.build());}}}}/*** 根据context内容构建数据源工厂*/private DataSourceFactory dataSourceElement(XNode context) throws Exception {if (context != null) {//获取type节点信息String type = context.getStringAttribute("type");//封装子节点信息Properties props = context.getChildrenAsProperties();//创建数据源工厂DataSourceFactory factory = (DataSourceFactory) resolveClass(type).getDeclaredConstructor().newInstance();//设置propsfactory.setProperties(props);return factory; //返回}throw new BuilderException("Environment declaration requires a DataSourceFactory.");}

这里不做详细解释了，根据节点信息生成对应工厂，最后将信息配置到configuration对象中下面看一下mappers节点解析吧

2.2 mappers节点解析

  /*** 解析mapper节点信息*/private void mapperElement(XNode parent) throws Exception {if (parent != null) {for (XNode child : parent.getChildren()) {//package 形式配置if ("package".equals(child.getName())) {//获取配置的nameString mapperPackage = child.getStringAttribute("name");//添加到configuration中的mapperRegistry中//这里会遍历package下的所有类进行处理configuration.addMappers(mapperPackage);} else {//获取resource,url,classString resource = child.getStringAttribute("resource");String url = child.getStringAttribute("url");String mapperClass = child.getStringAttribute("class");if (resource != null && url == null && mapperClass == null) {//当且仅当resource不为null时ErrorContext.instance().resource(resource);//获取resource对应配置文件信息InputStream inputStream = Resources.getResourceAsStream(resource);//根据resource配置信息生成XMLMapperBuilderXMLMapperBuilder mapperParser = new XMLMapperBuilder(inputStream, configuration, resource, configuration.getSqlFragments());//调用parse方法处理mapperParser.parse();} else if (resource == null && url != null && mapperClass == null) {//当且仅当url不为null时ErrorContext.instance().resource(url);InputStream inputStream = Resources.getUrlAsStream(url);XMLMapperBuilder mapperParser = new XMLMapperBuilder(inputStream, configuration, url, configuration.getSqlFragments());mapperParser.parse();} else if (resource == null && url == null && mapperClass != null) {//当且仅当mapperClass不为null时//根据配置mapperClass获取class对象Class<?> mapperInterface = Resources.classForName(mapperClass);//添加到configurationconfiguration.addMapper(mapperInterface);} else {	//没有进行配置或配置了多个都直接抛出异常throw new BuilderException("A mapper element may only specify a url, resource or class, but not more than one.");}}}}}

猛的一看，这if else看的让人头大有没有？仔细一看其实也没有什么特别难理解的逻辑，这里先判断是否为package配置，然后进行处理，否则就根据resource,url,class的配置进行不同处理，这里的三个参数只有配置一个的时候生效，不配置或者配置多个都不生效。

package 形式配置代码

  /*** 添加packageName到mapperRegistry中*/public void addMappers(String packageName) {mapperRegistry.addMappers(packageName);}/*** 根据packageName添加mapper* @since 3.2.2*/public void addMappers(String packageName) {addMappers(packageName, Object.class);}/*** 根据packageName添加mapper* @since 3.2.2*/public void addMappers(String packageName, Class<?> superType) {//创建ResolverUtil对象ResolverUtil<Class<?>> resolverUtil = new ResolverUtil<>();//调用resolverUtil的find方法进行处理//这里会用ResolverUtil.IsA来保存superType信息resolverUtil.find(new ResolverUtil.IsA(superType), packageName);//获取mappersetSet<Class<? extends Class<?>>> mapperSet = resolverUtil.getClasses();for (Class<?> mapperClass : mapperSet) {//调用addMapper处理addMapper(mapperClass);}}/*** 添加mapper的class*/public <T> void addMapper(Class<T> type) {if (type.isInterface()) {	//必须时接口文件才进行处理if (hasMapper(type)) {	//是否已存在 若存在则可能存在重复配置  是不被允许的 直接抛出异常throw new BindingException("Type " + type + " is already known to the MapperRegistry.");}boolean loadCompleted = false;try {//添加到knownMappers中 这是一个HashMap//MapperProxyFactory是Mapper接口对应的代理工厂knownMappers.put(type, new MapperProxyFactory<>(type));//根据config和type程间MapperAnnotationBuilder构造器MapperAnnotationBuilder parser = new MapperAnnotationBuilder(config, type);//处理parser.parse();loadCompleted = true;} finally {if (!loadCompleted) {knownMappers.remove(type);}}}}

从代码可知，这里会解析package路径下每个接口，对每个类生成一个创建一个代理对象工厂，注意，是代理对象的工厂，并未生成对应的代理对象，工厂生成之后创建了一个MapperAnnotationBuilder构造器，并调用了其parse方法，下面我们来看一下这个方法

  /*** 解析mapper*/public void parse() {//获取type的字符串形式  type是class类型String resource = type.toString();//判断resource是否已经加载过//这里用configuration中的loadedResources来记录已加载过的，防止重复加载if (!configuration.isResourceLoaded(resource)) {//加载mapper对应的xml路径loadXmlResource();//添加resource到configuration中的loadedResourcesconfiguration.addLoadedResource(resource);//设置命名空间assistant.setCurrentNamespace(type.getName());//处理CacheNamespace注解parseCache();//处理CacheNamespaceRef注解parseCacheRef();//获取type中所有方法进行遍历Method[] methods = type.getMethods();for (Method method : methods) {try {if (!method.isBridge()) {//方法处理parseStatement(method);}} catch (IncompleteElementException e) {configuration.addIncompleteMethod(new MethodResolver(this, method));}}}parsePendingMethods();}

这里会加载mapper的信息，并遍历其中每一个方法进行parseStatement处理

loadXmlResource()方法处理

  /*** 加载xml路径*/private void loadXmlResource() {//校验是否已经加载过if (!configuration.isResourceLoaded("namespace:" + type.getName())) {//获取对应的xml文件名String xmlResource = type.getName().replace('.', '/') + ".xml";//获取文件流InputStream inputStream = type.getResourceAsStream("/" + xmlResource);if (inputStream == null) {// Search XML mapper that is not in the module but in the classpath.try {inputStream = Resources.getResourceAsStream(type.getClassLoader(), xmlResource);} catch (IOException e2) {// ignore, resource is not required}}if (inputStream != null) {//创建XMLMapperBuilder解析inputStream中的信息XMLMapperBuilder xmlParser = new XMLMapperBuilder(inputStream, assistant.getConfiguration(), xmlResource, configuration.getSqlFragments(), type.getName());xmlParser.parse();}}}/*** 处理mapper的xml文件*/public void parse() {//是否加载过if (!configuration.isResourceLoaded(resource)) {//解析mapperconfigurationElement(parser.evalNode("/mapper"));//添加resource到configuration的loadedResources中configuration.addLoadedResource(resource);//通过命名空间绑定mapperbindMapperForNamespace();}//解析ResultMapparsePendingResultMaps();//解析CacheRefparsePendingCacheRefs();//解析StatementparsePendingStatements();}private void configurationElement(XNode context) {try {//获取命名空间namespaceString namespace = context.getStringAttribute("namespace");if (namespace == null || namespace.equals("")) {	//校验throw new BuilderException("Mapper's namespace cannot be empty");}builderAssistant.setCurrentNamespace(namespace);//缓存cache-ref节点信息 hashMapcacheRefElement(context.evalNode("cache-ref"));//开启二级缓存，相关处理cacheElement(context.evalNode("cache"));//解析parameterMapparameterMapElement(context.evalNodes("/mapper/parameterMap"));//解析resultMapresultMapElements(context.evalNodes("/mapper/resultMap"));//解析并缓存sql节点信息sqlElement(context.evalNodes("/mapper/sql"));//解析每个select|insert|update|delete节点信息buildStatementFromContext(context.evalNodes("select|insert|update|delete"));} catch (Exception e) {throw new BuilderException("Error parsing Mapper XML. The XML location is '" + resource + "'. Cause: " + e, e);}}

这里会解析接口对应的xml文件，解析每个标签，对每个select|insert|update|delete节点处理代码如下

  /*** 解析mapper.xml中的增删改查节点*/private void buildStatementFromContext(List<XNode> list) {if (configuration.getDatabaseId() != null) {buildStatementFromContext(list, configuration.getDatabaseId());}buildStatementFromContext(list, null);}/*** 解析mapper.xml中的增删改查节点*/private void buildStatementFromContext(List<XNode> list, String requiredDatabaseId) {for (XNode context : list) {//生成XMLStatementBuilder构建器final XMLStatementBuilder statementParser = new XMLStatementBuilder(configuration, builderAssistant, context, requiredDatabaseId);try {//构建statementParser.parseStatementNode();} catch (IncompleteElementException e) {configuration.addIncompleteStatement(statementParser);}}}public void parseStatementNode() {//获取节点的各个属性String id = context.getStringAttribute("id");String databaseId = context.getStringAttribute("databaseId");if (!databaseIdMatchesCurrent(id, databaseId, this.requiredDatabaseId)) {return;}String nodeName = context.getNode().getNodeName();SqlCommandType sqlCommandType = SqlCommandType.valueOf(nodeName.toUpperCase(Locale.ENGLISH));boolean isSelect = sqlCommandType == SqlCommandType.SELECT;boolean flushCache = context.getBooleanAttribute("flushCache", !isSelect);boolean useCache = context.getBooleanAttribute("useCache", isSelect);boolean resultOrdered = context.getBooleanAttribute("resultOrdered", false);XMLIncludeTransformer includeParser = new XMLIncludeTransformer(configuration, builderAssistant);includeParser.applyIncludes(context.getNode());String parameterType = context.getStringAttribute("parameterType");Class<?> parameterTypeClass = resolveClass(parameterType);String lang = context.getStringAttribute("lang");LanguageDriver langDriver = getLanguageDriver(lang);processSelectKeyNodes(id, parameterTypeClass, langDriver);KeyGenerator keyGenerator;String keyStatementId = id + SelectKeyGenerator.SELECT_KEY_SUFFIX;keyStatementId = builderAssistant.applyCurrentNamespace(keyStatementId, true);if (configuration.hasKeyGenerator(keyStatementId)) {keyGenerator = configuration.getKeyGenerator(keyStatementId);} else {keyGenerator = context.getBooleanAttribute("useGeneratedKeys",configuration.isUseGeneratedKeys() && SqlCommandType.INSERT.equals(sqlCommandType))? Jdbc3KeyGenerator.INSTANCE : NoKeyGenerator.INSTANCE;}SqlSource sqlSource = langDriver.createSqlSource(configuration, context, parameterTypeClass);StatementType statementType = StatementType.valueOf(context.getStringAttribute("statementType", StatementType.PREPARED.toString()));Integer fetchSize = context.getIntAttribute("fetchSize");Integer timeout = context.getIntAttribute("timeout");String parameterMap = context.getStringAttribute("parameterMap");String resultType = context.getStringAttribute("resultType");Class<?> resultTypeClass = resolveClass(resultType);String resultMap = context.getStringAttribute("resultMap");String resultSetType = context.getStringAttribute("resultSetType");ResultSetType resultSetTypeEnum = resolveResultSetType(resultSetType);if (resultSetTypeEnum == null) {resultSetTypeEnum = configuration.getDefaultResultSetType();}String keyProperty = context.getStringAttribute("keyProperty");String keyColumn = context.getStringAttribute("keyColumn");String resultSets = context.getStringAttribute("resultSets");//根据节点信息构建MappedStatementbuilderAssistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType,fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass,resultSetTypeEnum, flushCache, useCache, resultOrdered,keyGenerator, keyProperty, keyColumn, databaseId, langDriver, resultSets);}

addMappedStatement方法

  public MappedStatement addMappedStatement(String id,SqlSource sqlSource,StatementType statementType,SqlCommandType sqlCommandType,Integer fetchSize,Integer timeout,String parameterMap,Class<?> parameterType,String resultMap,Class<?> resultType,ResultSetType resultSetType,boolean flushCache,boolean useCache,boolean resultOrdered,KeyGenerator keyGenerator,String keyProperty,String keyColumn,String databaseId,LanguageDriver lang,String resultSets) {if (unresolvedCacheRef) {throw new IncompleteElementException("Cache-ref not yet resolved");}id = applyCurrentNamespace(id, false);boolean isSelect = sqlCommandType == SqlCommandType.SELECT;MappedStatement.Builder statementBuilder = new MappedStatement.Builder(configuration, id, sqlSource, sqlCommandType).resource(resource).fetchSize(fetchSize).timeout(timeout).statementType(statementType).keyGenerator(keyGenerator).keyProperty(keyProperty).keyColumn(keyColumn).databaseId(databaseId).lang(lang).resultOrdered(resultOrdered).resultSets(resultSets).resultMaps(getStatementResultMaps(resultMap, resultType, id)).resultSetType(resultSetType).flushCacheRequired(valueOrDefault(flushCache, !isSelect)).useCache(valueOrDefault(useCache, isSelect)).cache(currentCache);ParameterMap statementParameterMap = getStatementParameterMap(parameterMap, parameterType, id);if (statementParameterMap != null) {statementBuilder.parameterMap(statementParameterMap);}MappedStatement statement = statementBuilder.build();configuration.addMappedStatement(statement);return statement;}

然后我们回来看一下parseStatement方法得处理

  /*** 解析mapper中的方法*/void parseStatement(Method method) {//获取参数类型Class<?> parameterTypeClass = getParameterType(method);//获取语言驱动器LanguageDriver languageDriver = getLanguageDriver(method);//获取方法的SqlSource对象,只有指定了@Select/@Insert/@Update/@Delete或者对应的Provider的方法才会被当作mapper,否则只是和mapper文件中对应语句的一个运行时占位符SqlSource sqlSource = getSqlSourceFromAnnotations(method, parameterTypeClass, languageDriver);if (sqlSource != null) {//获取方法的属性设置，对应<select>中的各种属性Options options = method.getAnnotation(Options.class);final String mappedStatementId = type.getName() + "." + method.getName();Integer fetchSize = null;Integer timeout = null;StatementType statementType = StatementType.PREPARED;ResultSetType resultSetType = configuration.getDefaultResultSetType();//获取语句的CRUD类型SqlCommandType sqlCommandType = getSqlCommandType(method);boolean isSelect = sqlCommandType == SqlCommandType.SELECT;boolean flushCache = !isSelect;boolean useCache = isSelect;KeyGenerator keyGenerator;String keyProperty = null;String keyColumn = null;//只有INSERT/UPDATE才解析SelectKey选项if (SqlCommandType.INSERT.equals(sqlCommandType) || SqlCommandType.UPDATE.equals(sqlCommandType)) {SelectKey selectKey = method.getAnnotation(SelectKey.class);if (selectKey != null) {keyGenerator = handleSelectKeyAnnotation(selectKey, mappedStatementId, getParameterType(method), languageDriver);keyProperty = selectKey.keyProperty();} else if (options == null) {keyGenerator = configuration.isUseGeneratedKeys() ? Jdbc3KeyGenerator.INSTANCE : NoKeyGenerator.INSTANCE;} else {keyGenerator = options.useGeneratedKeys() ? Jdbc3KeyGenerator.INSTANCE : NoKeyGenerator.INSTANCE;keyProperty = options.keyProperty();keyColumn = options.keyColumn();}} else {keyGenerator = NoKeyGenerator.INSTANCE;}if (options != null) {if (FlushCachePolicy.TRUE.equals(options.flushCache())) {flushCache = true;} else if (FlushCachePolicy.FALSE.equals(options.flushCache())) {flushCache = false;}useCache = options.useCache();fetchSize = options.fetchSize() > -1 || options.fetchSize() == Integer.MIN_VALUE ? options.fetchSize() : null; //issue #348timeout = options.timeout() > -1 ? options.timeout() : null;statementType = options.statementType();if (options.resultSetType() != ResultSetType.DEFAULT) {resultSetType = options.resultSetType();}}String resultMapId = null;//解析@ResultMap注解,如果有@ResultMap注解,就是用它，否则才解析@Results//@ResultMap注解用于给@Select和@SelectProvider注解提供在xml配置的<resultMap>,如果一个方法上同时出现@Results或者@ConstructorArgs等和结果映射有关的注解,那么@ResultMap会覆盖后面两者的注解ResultMap resultMapAnnotation = method.getAnnotation(ResultMap.class);if (resultMapAnnotation != null) {resultMapId = String.join(",", resultMapAnnotation.value());} else if (isSelect) {//如果是查询，且没有明确设置ResultMap，则根据返回类型自动解析生成ResultMapresultMapId = parseResultMap(method);}assistant.addMappedStatement(mappedStatementId,sqlSource,statementType,sqlCommandType,fetchSize,timeout,// ParameterMapIDnull,parameterTypeClass,resultMapId,getReturnType(method),resultSetType,flushCache,useCache,// TODO gcode issue #577false,keyGenerator,keyProperty,keyColumn,// DatabaseIDnull,languageDriver,// ResultSetsoptions != null ? nullOrEmpty(options.resultSets()) : null);}}

================================================================================================

================================================================================================

总结：

    	//获取配置文件信息流InputStream stream = Demo.class.getClassLoader().getResourceAsStream("mybatis.xml");//使用SqlSessionFactory构建器，读取配置文件构建出一个sessionFactorySqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(stream);

这两行代码主要是解析mybatis配置文件，包含配置文件的各种信息，然后把解析到的信息封装到Configuration对象中，然后根据Configuration对象创建一个DefaultSqlSessionFactory对象返回。

最后上一下Configuration类的源码

public class Configuration {protected Environment environment;protected boolean safeRowBoundsEnabled;protected boolean safeResultHandlerEnabled = true;protected boolean mapUnderscoreToCamelCase;protected boolean aggressiveLazyLoading;protected boolean multipleResultSetsEnabled = true;protected boolean useGeneratedKeys;protected boolean useColumnLabel = true;protected boolean cacheEnabled = true;protected boolean callSettersOnNulls;protected boolean useActualParamName = true;protected boolean returnInstanceForEmptyRow;protected String logPrefix;protected Class<? extends Log> logImpl;protected Class<? extends VFS> vfsImpl;protected LocalCacheScope localCacheScope = LocalCacheScope.SESSION;protected JdbcType jdbcTypeForNull = JdbcType.OTHER;protected Set<String> lazyLoadTriggerMethods = new HashSet<>(Arrays.asList("equals", "clone", "hashCode", "toString"));protected Integer defaultStatementTimeout;protected Integer defaultFetchSize;protected ResultSetType defaultResultSetType;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 OGNLprotected String databaseId;/*** Configuration factory class.* Used to create Configuration for loading deserialized unread properties.** @see <a href='https://code.google.com/p/mybatis/issues/detail?id=300'>Issue 300 (google code)</a>*/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<String, MappedStatement> mappedStatements = new StrictMap<MappedStatement>("Mapped Statements collection").conflictMessageProducer((savedValue, targetValue) ->". please check " + savedValue.getResource() + " and " + targetValue.getResource());protected final Map<String, Cache> caches = new StrictMap<>("Caches collection");protected final Map<String, ResultMap> resultMaps = new StrictMap<>("Result Maps collection");protected final Map<String, ParameterMap> parameterMaps = new StrictMap<>("Parameter Maps collection");protected final Map<String, KeyGenerator> keyGenerators = new StrictMap<>("Key Generators collection");protected final Set<String> loadedResources = new HashSet<>();protected final Map<String, XNode> sqlFragments = new StrictMap<>("XML fragments parsed from previous mappers");protected final Collection<XMLStatementBuilder> incompleteStatements = new LinkedList<>();protected final Collection<CacheRefResolver> incompleteCacheRefs = new LinkedList<>();protected final Collection<ResultMapResolver> incompleteResultMaps = new LinkedList<>();protected final Collection<MethodResolver> 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<String, String> 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);}
//后面省略--------
}