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mybatis源码分析

2020-04-23 16:17:42   105  举报

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mybatis源码分析

MyBatis

作者其他创作

大纲/内容

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