Mybatis持久化框架源码阅读2-配置文件解析
最经典的使用代码示例：
String resource = "mybatis-config.xml";
//将XML配置文件构建为Configuration配置类
Reader reader = Resources.getResourceAsReader(resource);
// 通过加载配置文件流构建一个SqlSessionFactory 解析xml文件 1
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);通过SqlSessionFactoryBuilder()来对配置文件进行各种解析及初始化。
1.build(reader)内部使用new XMLConfigBuilder()工具类解析xml格式文件
new XPathParser(reader)具体解析器,把xml解析成内部Document对象提供后续分解使用，解析整体流程：
2.XMLConfigBuilder()构造方法:
关键点:new Configuration()声明一个configuration对象,默认了很多组件
XMLConfigBuilder初始化调用父类构造方法,
XMLConfigBuilder的父类构造方法默认组件，Configuration是Mybatis的全局配置类，包含Mapper注册工厂等。
public BaseBuilder(Configuration configuration) {
this.configuration = configuration;
//POJO默认别名
this.typeAliasRegistry = this.configuration.getTypeAliasRegistry();
//参数/返回值类型处理映射
this.typeHandlerRegistry = this.configuration.getTypeHandlerRegistry();
}Configuration类是重点配置对象
包含MyBatis所有配置信息,在构造方法默认很多别名组件,使xml在配置时,使用JDBC就直接使用JdbcTransactionFactory.class
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);
}Configuration在初始化时，默认了很多内部属性。
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 OGNL
protected 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();
// 类型别名注册器 TypeAliasRegistry构造函数会注册一些， Configuration构造函数会注册一些
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;
}
//...省略
}其中MapperRegistry属性在注册Mapper时就会解析接口方法上是否使用了注解,如@Select @Insert @Update @Delete @SelectProvider @InsertProvider @UpdateProvider @DeleteProvider
//Mapper注册器工具类
protected final MapperRegistry mapperRegistry = new MapperRegistry(this);
protected final InterceptorChain interceptorChain = new InterceptorChain();
//入参回参类型解析处理器
protected final TypeHandlerRegistry typeHandlerRegistry = new TypeHandlerRegistry();
// 类型别名注册器 TypeAliasRegistry构造函数会注册一些， Configuration构造函数会注册一些
protected final TypeAliasRegistry typeAliasRegistry = new TypeAliasRegistry();3.XMLConfigBUilder.parse()开始解析配置
1.解析的整体流程
最重要的解析xml方法，声明XMLConfigBuilder(reader, environment, properties)并传入xml的Reader对象后,调用XMLConfigBuilder.parse()方法解析xml内容,跟节点是/configuration,看文档 mybatis解析xml配置文件
/**
* 方法实现说明:解析我们mybatis-config.xml的 configuration节点
* @author:xsls
* @param root:configuration节点对象
* @return:
* @exception:
* @date:2019/8/30 15:57
*/
private void parseConfiguration(XNode root) {
try {
/**
* 解析 properties节点
* <properties resource="mybatis/db.properties" />
* 解析到org.apache.ibatis.parsing.XPathParser#variables
* org.apache.ibatis.session.Configuration#variables
*/
propertiesElement(root.evalNode("properties"));
/**
* 解析我们的mybatis-config.xml中的settings节点
* 具体可以配置哪些属性:http://www.mybatis.org/mybatis-3/zh/configuration.html#settings
* <settings>
<setting name="cacheEnabled" value="true"/>
<setting name="lazyLoadingEnabled" value="true"/>
<setting name="mapUnderscoreToCamelCase" value="false"/>
<setting name="localCacheScope" value="SESSION"/>
<setting name="jdbcTypeForNull" value="OTHER"/>
..............
</settings>
*
*/
Properties settings = settingsAsProperties(root.evalNode("settings"));
/**
* 基本没有用过该属性
* VFS含义是虚拟文件系统；主要是通过程序能够方便读取本地文件系统、FTP文件系统等系统中的文件资源。
Mybatis中提供了VFS这个配置，主要是通过该配置可以加载自定义的虚拟文件系统应用程序
解析到：org.apache.ibatis.session.Configuration#vfsImpl
*/
loadCustomVfs(settings);
/**
* 指定 MyBatis 所用日志的具体实现，未指定时将自动查找。
* SLF4J | LOG4J | LOG4J2 | JDK_LOGGING | COMMONS_LOGGING | STDOUT_LOGGING | NO_LOGGING
* 解析到org.apache.ibatis.session.Configuration#logImpl
*/
loadCustomLogImpl(settings);
/**
* 解析我们的别名
* <typeAliases>
<typeAlias alias="Author" type="cn.liutx.pojo.Author"/>
</typeAliases>
<typeAliases>
<package name="cn.liutx.pojo"/>
</typeAliases>
解析到oorg.apache.ibatis.session.Configuration#typeAliasRegistry.typeAliases
除了自定义的，还有内置的
*/
typeAliasesElement(root.evalNode("typeAliases"));
/**
* 解析我们的插件(比如分页插件)
* mybatis自带的
* Executor (update, query, flushStatements, commit, rollback, getTransaction, close, isClosed)
ParameterHandler (getParameterObject, setParameters)
ResultSetHandler (handleResultSets, handleOutputParameters)
StatementHandler (prepare, parameterize, batch, update, query)
解析到：org.apache.ibatis.session.Configuration#interceptorChain.interceptors
*/
pluginElement(root.evalNode("plugins"));
/**
* 可以配置 一般不会去设置
* 对象工厂 用于反射实例化对象、对象包装工厂、
* 反射工厂 用于属性和setter/getter 获取
*/
objectFactoryElement(root.evalNode("objectFactory"));
objectWrapperFactoryElement(root.evalNode("objectWrapperFactory"));
reflectorFactoryElement(root.evalNode("reflectorFactory"));
// 设置settings 和默认值到configuration
settingsElement(settings);
/**
* 解析我们的mybatis环境
<environments default="dev">
<environment id="dev">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="root"/>
<property name="password" value="Zw726515"/>
</dataSource>
</environment>
<environment id="test">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
* 解析到：org.apache.ibatis.session.Configuration#environment
* 在集成spring情况下由 spring-mybatis提供数据源 和事务工厂
*/
environmentsElement(root.evalNode("environments"));
/**
* 解析数据库厂商
* <databaseIdProvider type="DB_VENDOR">
<property name="SQL Server" value="sqlserver"/>
<property name="DB2" value="db2"/>
<property name="Oracle" value="oracle" />
<property name="MySql" value="mysql" />
</databaseIdProvider>
* 解析到：org.apache.ibatis.session.Configuration#databaseId
*/
databaseIdProviderElement(root.evalNode("databaseIdProvider"));
/**
* 解析我们的类型处理器节点
* <typeHandlers>
<typeHandler handler="org.mybatis.example.ExampleTypeHandler"/>
</typeHandlers>
解析到：org.apache.ibatis.session.Configuration#typeHandlerRegistry.typeHandlerMap
*/
typeHandlerElement(root.evalNode("typeHandlers"));
/**
* 解析我们的mapper
*
resource：来注册我们的class类路径下的
url:来指定我们磁盘下的或者网络资源的
class:
若注册Mapper不带xml文件的,这里可以直接注册
若注册的Mapper带xml文件的，需要把xml文件和mapper文件同名 同路径
-->
<mappers>
<mapper resource="mybatis/mapper/EmployeeMapper.xml"/>
<mapper class="com.liutx.mapper.DeptMapper"></mapper>
<package name="com.liutx.mapper"></package>
-->
</mappers>
* package
* ·解析mapper接口代理工厂（传入需要代理的接口） 解析到：org.apache.ibatis.session.Configuration#mapperRegistry.knownMappers
·解析mapper.xml 最终解析成MappedStatement 到：org.apache.ibatis.session.Configuration#mappedStatements
*/
mapperElement(root.evalNode("mappers"));
} catch (Exception e) {
throw new BuilderException("Error parsing SQL Mapper Configuration. Cause: " + e, e);
}
}2.mapperElement(Node)解析xml文件，判断各种解析方式
四种解析方式,
配置package扫描
<package name="com.liutx.mapper"></package>判断从classpath下读取我们的mapper
<mapper resource="mybatis/mapper/EmployeeMapper.xml"/>判断是不是从我们的网络资源读取(或者本地磁盘得)
<mapper url="D:/mapper/EmployeeMapper.xml"/>解析这种类型(要求接口和xml在同一个包下)
<mapper class="com.liutx.mapper.DeptMapper"></mapper>
/**
* 方法实现说明
* @author:xsls
* @param parent:mappers
* @return:
* @exception:
* @date:2019/8/30 16:32
*/
private void mapperElement(XNode parent) throws Exception {
if (parent != null) {
/**
* 获取我们mappers节点下的一个一个的mapper节点
*/
for (XNode child : parent.getChildren()) {
/**
* 判断我们mapper是不是通过批量注册的
* <package name="com.liutx.mapper"></package>
*/
if ("package".equals(child.getName())) {
String mapperPackage = child.getStringAttribute("name");
configuration.addMappers(mapperPackage);
} else {
/**
* 判断从classpath下读取我们的mapper
* <mapper resource="mybatis/mapper/EmployeeMapper.xml"/>
*/
String resource = child.getStringAttribute("resource");
/**
* 判断是不是从我们的网络资源读取(或者本地磁盘得)
* <mapper url="D:/mapper/EmployeeMapper.xml"/>
*/
String url = child.getStringAttribute("url");
/**
* 解析这种类型(要求接口和xml在同一个包下)
* <mapper class="com.liutx.mapper.DeptMapper"></mapper>
*
*/
String mapperClass = child.getStringAttribute("class");
/**
* 我们得mappers节点只配置了
* <mapper resource="mybatis/mapper/EmployeeMapper.xml"/>
*/
if (resource != null && url == null && mapperClass == null) {
ErrorContext.instance().resource(resource);
/**
* 把我们的文件读取出一个流
*/
InputStream inputStream = Resources.getResourceAsStream(resource);
/**
* 创建读取XmlMapper构建器对象,用于来解析我们的mapper.xml文件
*/
XMLMapperBuilder mapperParser = new XMLMapperBuilder(inputStream, configuration, resource, configuration.getSqlFragments());
/**
* 真正的解析我们的mapper.xml配置文件(说白了就是来解析我们的sql)
*/
mapperParser.parse();
} else if (resource == null && url != null && mapperClass == null) {
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) {
Class<?> mapperInterface = Resources.classForName(mapperClass);
configuration.addMapper(mapperInterface);
} else {
throw new BuilderException("A mapper element may only specify a url, resource or class, but not more than one.");
}
}
}
}
}3.使用XMLMapperBuilder.parse()对mapper.xml进行解析
/**
* 方法实现说明:真正的去解析我们的Mapper.xml(EmployeeMapper.xml)
* @author:xsls
* @return:
* @exception:
* @date:2019/8/30 16:43
*/
public void parse() {
/**
* 判断当前的Mapper是否被加载过
*/
if (!configuration.isResourceLoaded(resource)) {
/**
* 真正的解析我们的 <mapper namespace="com.liutx.mapper.EmployeeMapper">
*
*/
configurationElement(parser.evalNode("/mapper"));
/**
* 把资源保存到我们Configuration中
*/
configuration.addLoadedResource(resource);
bindMapperForNamespace();
}
parsePendingResultMaps();
parsePendingCacheRefs();
parsePendingStatements();
}扫描包的方式进行解析,先扫描出interface全限定名,在使用MapperAnnotationBuilder.parse()进行解析,解析注解也使用XMLMapperBuilder解析mapper.xml
解析包路径：
/**
* 判断我们mapper是不是通过批量注册的
* <package name="com.tuling.mapper"></package>
*/
if ("package".equals(child.getName())) {
String mapperPackage = child.getStringAttribute("name");
configuration.addMappers(mapperPackage);
}
具体的解析方法在addMapper()中。
4.Mybatis的事务实现
默认使用的是JdbcTransactionFactory. 在与Spring结合后使用的是SpringManagedTransactionFactory
在new Configuration()时提供了默认的类型的别名:
typeAliasRegistry.registerAlias("JDBC", JdbcTransactionFactory.class);typeAliasRegistry.registerAlias("MANAGED", ManagedTransactionFactory.class);
在xml加载初始化时解析environments环境变量就会读取jdbc配置和事物配置.
在sqlSessionFactory.openSqlsession()时会获取事物配置,new出一个事物
与Spring结合
集成Spring的时候,spring扫描并实例化SqlSessionFactoryBean会调用getObject方法,在afterPropertiesSet()方法中buildSqlSessionFactory()初始化各项配置, 其中数据库事物使用SpringManagedTransactionFactory(),内部使用事务同步器获取数据库链接
/**
* 为我们的configuration设置一个环境变量
*/
targetConfiguration.setEnvironment(new Environment(this.environment,
this.transactionFactory == null ? new SpringManagedTransactionFactory(): this.transactionFactory,
this.dataSource)
);
默认JdbcTranscation
Mybatis自己实现JdbcTransactionFactory,从dataSources获取数据库链接
public class JdbcTransaction implements Transaction {
private static final Log log = LogFactory.getLog(JdbcTransaction.class);
protected Connection connection;
protected DataSource dataSource;
protected TransactionIsolationLevel level;
protected boolean autoCommit;
public JdbcTransaction(DataSource ds, TransactionIsolationLevel desiredLevel, boolean desiredAutoCommit) {
dataSource = ds;
level = desiredLevel;
autoCommit = desiredAutoCommit;
}
public JdbcTransaction(Connection connection) {
this.connection = connection;
}
@Override
public Connection getConnection() throws SQLException {
if (connection == null) {
openConnection();
}
return connection;
}
@Override
public void commit() throws SQLException {
if (connection != null && !connection.getAutoCommit()) {
if (log.isDebugEnabled()) {
log.debug("Committing JDBC Connection [" + connection + "]");
}
connection.commit();
}
}
@Override
public void rollback() throws SQLException {
if (connection != null && !connection.getAutoCommit()) {
if (log.isDebugEnabled()) {
log.debug("Rolling back JDBC Connection [" + connection + "]");
}
connection.rollback();
}
}
@Override
public void close() throws SQLException {
if (connection != null) {
resetAutoCommit();
if (log.isDebugEnabled()) {
log.debug("Closing JDBC Connection [" + connection + "]");
}
connection.close();
}
}
protected void setDesiredAutoCommit(boolean desiredAutoCommit) {
try {
if (connection.getAutoCommit() != desiredAutoCommit) {
if (log.isDebugEnabled()) {
log.debug("Setting autocommit to " + desiredAutoCommit + " on JDBC Connection [" + connection + "]");
}
connection.setAutoCommit(desiredAutoCommit);
}
} catch (SQLException e) {
// Only a very poorly implemented driver would fail here,
// and there's not much we can do about that.
throw new TransactionException("Error configuring AutoCommit. "
+ "Your driver may not support getAutoCommit() or setAutoCommit(). "
+ "Requested setting: " + desiredAutoCommit + ". Cause: " + e, e);
}
}
protected void resetAutoCommit() {
try {
if (!connection.getAutoCommit()) {
// MyBatis does not call commit/rollback on a connection if just selects were performed.
// Some databases start transactions with select statements
// and they mandate a commit/rollback before closing the connection.
// A workaround is setting the autocommit to true before closing the connection.
// Sybase throws an exception here.
if (log.isDebugEnabled()) {
log.debug("Resetting autocommit to true on JDBC Connection [" + connection + "]");
}
connection.setAutoCommit(true);
}
} catch (SQLException e) {
if (log.isDebugEnabled()) {
log.debug("Error resetting autocommit to true "
+ "before closing the connection. Cause: " + e);
}
}
}
protected void openConnection() throws SQLException {
if (log.isDebugEnabled()) {
log.debug("Opening JDBC Connection");
}
connection = dataSource.getConnection();
if (level != null) {
connection.setTransactionIsolation(level.getLevel());
}
setDesiredAutoCommit(autoCommit);
}
@Override
public Integer getTimeout() throws SQLException {
return null;
}
}触发的点在DefaultSqlSessionFactory.openSession()中，执行sql之前会先获取并打开数据库连接，执行的有openSessionFromDataSource()方法，内部判断并获取事务工厂。
Transaction tx = null;
/**
* 获取事务工厂
*/
final TransactionFactory transactionFactory = getTransactionFactoryFromEnvironment(environment);
tx = transactionFactory.newTransaction(environment.getDataSource(), level, autoCommit);以前我们在Mybatis-config.xml中经常看到此JDBC的配置：
<environments default="dev">
<environment id="dev">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="root"/>
<property name="password" value="Zw726515"/>
</dataSource>
</environment>
</environments>由容器实现
ManagedTransactionFactory是Mybatis不实现事物,由容器来管理事物，内部只有开启和关闭数据库连接，但是没有commit和roback操作。
public class ManagedTransaction implements Transaction {
private static final Log log = LogFactory.getLog(ManagedTransaction.class);
private DataSource dataSource;
private TransactionIsolationLevel level;
private Connection connection;
private final boolean closeConnection;
public ManagedTransaction(Connection connection, boolean closeConnection) {
this.connection = connection;
this.closeConnection = closeConnection;
}
public ManagedTransaction(DataSource ds, TransactionIsolationLevel level, boolean closeConnection) {
this.dataSource = ds;
this.level = level;
this.closeConnection = closeConnection;
}
@Override
public Connection getConnection() throws SQLException {
if (this.connection == null) {
openConnection();
}
return this.connection;
}
@Override
public void commit() throws SQLException {
// Does nothing
}
@Override
public void rollback() throws SQLException {
// Does nothing
}
@Override
public void close() throws SQLException {
if (this.closeConnection && this.connection != null) {
if (log.isDebugEnabled()) {
log.debug("Closing JDBC Connection [" + this.connection + "]");
}
this.connection.close();
}
}
protected void openConnection() throws SQLException {
if (log.isDebugEnabled()) {
log.debug("Opening JDBC Connection");
}
this.connection = this.dataSource.getConnection();
if (this.level != null) {
this.connection.setTransactionIsolation(this.level.getLevel());
}
}
@Override
public Integer getTimeout() throws SQLException {
return null;
}
}//下一次了解一下Mbatis的两种注解方式，第一种MapperScan扫描包，第二种在接口上使用@Mapper注解。
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