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mybatis源码分析

2020-04-23 16:17:42   106  举报

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mybatis源码分析

MyBatis

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获取SqlSessionFactory对象

new SqlSessionFactoryBuilder()

执行build方法, 返回SqlSessionFactory对象

XMLConfigBuilder parser = new XMLConfigBuilder(inputStream, environment, properties); 创建XMLConfigBuilder对象,并初始化字段

this.configuration = configuration;

this.typeAliasRegistry = this.configuration.getTypeAliasRegistry();

this.typeHandlerRegistry = this.configuration.getTypeHandlerRegistry();

this.environment = environment;

this.parser = new XPathParser(inputStream, true, props, new XMLMapperEntityResolver() 创建XPathParser解析器

parser.parse() 解析全局配置文件

parseConfiguration

propertiesElement 解析<properties>元素

Properties defaults = context.getChildrenAsProperties(); 添加子元素内容至defaults

defaults =Resources.getResourceAsProperties(resource) 读取外部properties文件内容至defaults

parser.setVariables(defaults); XPathParser添加变量信息

configuration.setVariables(defaults)

settingsAsProperties 解析<settings>元素 mybatis全局设置

Properties props = context.getChildrenAsProperties(); 获取子元素内容

metaConfig.hasSetter(String.valueOf(key) 校验子元素是否合法

typeAliasesElement 解析<typeAliases>元素 类型别名

pluginElement 解析<plugIns>元素 插件

获取拦截器 child.getStringAttribute("interceptor");

获取属性 child.getChildrenAsProperties()

创建拦截器实例 Interceptor interceptorInstance = (Interceptor) resolveClass(interceptor).getDeclaredConstructor().newInstance();

添加拦截器至configuration全局变量中  configuration.addInterceptor(interceptorInstance)

objectFactoryElement 解析<objectFactory>元素

objectWrapperFactoryElement 解析<objectWrapperFactory>元素

reflectorFactoryElement 解析<reflectorFactory>元素

settingsElement 将<settings>元素内容填充至configuration对象中

将<settings>元素配置的全局属性添加至configuration中

configuration.setCacheEnabled(booleanValueOf(props.getProperty("cacheEnabled"), true));

configuration.setMapUnderscoreToCamelCase(booleanValueOf(props.getProperty("mapUnderscoreToCamelCase"), false));

....

databaseIdProviderElement 解析<databaseIdProvider>元素 数据库厂商标识

typeHandlerElement 解析<typeHandlers>元素

mapperElement 解析<mappers>元素

package

configuration.addMappers(mapperPackage)

MapperRegistry-> addMappers(packageName);

resolverUtil.find(new ResolverUtil.IsA(superType), packageName); 解析指定包中Class

addMapper(mapperClass);

knownMappers.put(type, new MapperProxyFactory<>(type)); 添加MapperProxy代理对象

MapperAnnotationBuilder->parse() 解析Mapper接口中定义的注解

MapperAnnotationBuilder-> loadXmlResource(); 加载xml映射文件

InputStream inputStream = type.getResourceAsStream("/" + xmlResource);

inputStream = Resources.getResourceAsStream(type.getClassLoader(), xmlResource);

XMLMapperBuilder xmlParser = new XMLMapperBuilder(inputStream, assistant.getConfiguration(), xmlResource, configuration.getSqlFragments(), type.getName()); xmlParser.parse();

MapperAnnotationBuilder-> parseStatement(method);

MapperBuilderAssistant-> addMappedStatement

mapper

resource url

Resources.getResourceAsStream(resource) 加载资源文件为流

XMLMapperBuilder-> parse() 解析<mapper>元素

configurationElement

namespace

cacheRefElement 解析cache-ref属性

cacheElement 解析cache属性

parameterMapElement /mapper/parameterMap

builderAssistant.addParameterMap

resultMapElements /mapper/resultMap

sqlElement /mapper/sql

buildStatementFromContext select|insert|update|delete

XMLStatementBuilder-> parseStatementNode();

解析xml元素

MapperBuilderAssistant-> addMappedStatement

MappedStatement statement = statementBuilder.build();

configuration.addMappedStatement(statement);

bindMapperForNamespace

builderAssistant.getCurrentNamespace()

configuration.addLoadedResource("namespace:" + namespace);

configuration.addMapper(boundType);

parsePendingResultMaps

parsePendingCacheRefs

parsePendingStatements

class

Resources.classForName(mapperClass);

configuration.addMapper(boundType);

获取SqlSession对象

DefaultSqlSessionFactory-> openSession()

DefaultSqlSessionFactory-> openSessionFromDataSource

configuration.getEnvironment() 获取环境变量

tx = transactionFactory.newTransaction(); 创建事务

Executor executor = configuration.newExecutor(tx, execType) 创建执行器

BatchExecutor 执行器不仅重用语句还会执行批量更新

ReuseExecutor 执行器会重用预处理语句（PreparedStatement）

SimpleExecutor 普通的执行器

CachingExecutor setting中开启二级缓存(cacheEnabled=true)

executor = (Executor) interceptorChain.pluginAll(executor); 拦截器处理,插件对执行器进行二次包装

new DefaultSqlSession(configuration, executor, autoCommit); 返回DefaultSqlSession对象

获取接口代理对象 MapperProxy

DefaultSqlSession-> getMapper(Class<T> type)

Configuration-> getMapper

MapperRegistry-> getMapper

(MapperProxyFactory<T>) knownMappers.get(type)

mapperProxyFactory.newInstance(sqlSession)

MapperProxy<T> mapperProxy = new MapperProxy<>(sqlSession, mapperInterface, methodCache);

(T) Proxy.newProxyInstance(mapperInterface.getClassLoader(), new Class[] { mapperInterface }, mapperProxy);

执行增删改查方法

MapperProxy-> invoke() 进入代理对象invoke方法

Object上定义的方法直接执行

MapperMethod-> execute

command.getType() INSERT|UPDATE|DELETE|SELECT

executeForMany

method.convertArgsToSqlCommandParam

paramNameResolver.getNamedParams(args)

sqlSession.selectList(command.getName(), param)

DefaultSqlSession-> configuration.getMappedStatement(statement)

wrapCollection() 参数统一封装为map

executor.query 执行器查询

MappedStatement-> ms.getBoundSql(parameterObject)

query

先查询缓存

delegate.query

BaseExecutor-> queryFromDatabase

doQuery

ms.getConfiguration();

StatementHandler handler = configuration.newStatementHandler();

StatementHandler statementHandler = new RoutingStatementHandler

STATEMENT:SimpleStatementHandler

PREPARED:PreparedStatementHandler

CALLABLE:CallableStatementHandler

BaseStatementHandler->

this.parameterHandler = configuration.newParameterHandler 创建参数处理器

(ParameterHandler) interceptorChain.pluginAll(parameterHandler);

this.resultSetHandler = configuration.newResultSetHandler 创建结果处理器

resultSetHandler = (ResultSetHandler) interceptorChain.pluginAll(resultSetHandler);

(StatementHandler) interceptorChain.pluginAll(statementHandler);

stmt = prepareStatement(handler, ms.getStatementLog());

Connection connection = getConnection(statementLog);

JdbcTransaction-> transaction.getConnection(); 获取数据库连接

dataSource.getConnection() 从连接池获取connection

connection.setAutoCommit(desiredAutoCommit); 设置事务

stmt = handler.prepare(connection, transaction.getTimeout());

RoutingStatementHandler-> delegate.prepare(connection, transactionTimeout);

BaseStatementHandler-> prepare

instantiateStatement

PreparedStatementHandler-> String sql = boundSql.getSql() connection.prepareStatement(sql)

setStatementTimeout

setFetchSize

return statement

handler.parameterize(stmt);

RoutingStatementHandler-> delegate.parameterize(statement);

PreparedStatementHandler-> parameterHandler.setParameters((PreparedStatement) statement);

DefaultParameterHandler-> TypeHandler typeHandler = parameterMapping.getTypeHandler(); JdbcType jdbcType = parameterMapping.getJdbcType(); typeHandler.setParameter(ps, i + 1, value, jdbcType);

handler.query(stmt, resultHandler);

RoutingStatementHandler-> delegate.query(statement, resultHandler);

PreparedStatementHandler-> PreparedStatement ps = (PreparedStatement) statement; ps.execute();

resultSetHandler.handleResultSets(ps); 处理参数