1.SqlSessionFactoryBuilder
public SqlSessionFactory build(InputStream inputStream, String environment, Properties properties) {
SqlSessionFactory var5;
try {//通过XML
XMLConfigBuilder parser = new XMLConfigBuilder(inputStream, environment, properties);
var5 = this.build(parser.parse());
} catch (Exception var14) {
throw ExceptionFactory.wrapException("Error building SqlSession.", var14);
} finally {
ErrorContext.instance().reset();
try {
inputStream.close();
} catch (IOException var13) {
;
}
}
return var5;
}
public SqlSessionFactory build(Configuration config) {
return new DefaultSqlSessionFactory(config);
}
2.BaseBuilder
public abstract class BaseBuilder {
protected final Configuration configuration;
protected final TypeAliasRegistry typeAliasRegistry;
protected final TypeHandlerRegistry typeHandlerRegistry;
public BaseBuilder(Configuration configuration) {
this.configuration = configuration;
this.typeAliasRegistry = this.configuration.getTypeAliasRegistry();
this.typeHandlerRegistry = this.configuration.getTypeHandlerRegistry();
}
...
}
3.XMLConfigBuilder extends BaseBuilder
public Configuration parse() {
if (this.parsed) {
throw new BuilderException("Each MapperConfigParser can only be used once.");
} else {
this.parsed = true;
this.parseConfiguration(this.parser.evalNode("/configuration"));
return this.configuration;
}
}
private void parseConfiguration(XNode root) {
try {
this.propertiesElement(root.evalNode("properties"));
this.typeAliasesElement(root.evalNode("typeAliases"));
this.pluginElement(root.evalNode("plugins"));
this.objectFactoryElement(root.evalNode("objectFactory"));
this.objectWrapperFactoryElement(root.evalNode("objectWrapperFactory"));
this.settingsElement(root.evalNode("settings"));
this.environmentsElement(root.evalNode("environments"));
this.databaseIdProviderElement(root.evalNode("databaseIdProvider"));
this.typeHandlerElement(root.evalNode("typeHandlers"));
//解析mappers指定的映射文件，将MapperStatement信息加载至configuration
this.mapperElement(root.evalNode("mappers"));
} catch (Exception var3) {
throw new BuilderException("Error parsing SQL Mapper Configuration. Cause: " + var3, var3);
}
}
根据指定mapper映射文件的方式对mappers标签进行解析
<mappers>
<mapper resource="com/abc/dao/mapper.xml"/>
</mappers>
<mappers>
<mapper url="file:///E:\workspace\com/abc/dao/mapper.xml"/>
</mappers>
<mappers>
<mapper class="com.abc.dao.IStudentDao"/>
</mappers>
<mappers>
<mapper package="com.abc.dao"/>
</mappers>
private void mapperElement(XNode parent) throws Exception {
if (parent != null) {
Iterator i$ = parent.getChildren().iterator();
while(true) {
while(i$.hasNext()) {
XNode child = (XNode)i$.next();
String resource;
if ("package".equals(child.getName())) {
resource = child.getStringAttribute("name");
this.configuration.addMappers(resource);
} else {
resource = child.getStringAttribute("resource");
String url = child.getStringAttribute("url");
String mapperClass = child.getStringAttribute("class");
XMLMapperBuilder mapperParser;
InputStream inputStream;
if (resource != null && url == null && mapperClass == null) {
ErrorContext.instance().resource(resource);
inputStream = Resources.getResourceAsStream(resource);
mapperParser = new XMLMapperBuilder(inputStream, this.configuration, resource, this.configuration.getSqlFragments());
mapperParser.parse();
} else if (resource == null && url != null && mapperClass == null) {
ErrorContext.instance().resource(url);
inputStream = Resources.getUrlAsStream(url);
mapperParser = new XMLMapperBuilder(inputStream, this.configuration, url, this.configuration.getSqlFragments());
mapperParser.parse();
} else {
if (resource != null || url != null || mapperClass == null) {
throw new BuilderException("A mapper element may only specify a url, resource or class, but not more than one.");
}
Class<?> mapperInterface = Resources.classForName(mapperClass);
this.configuration.addMapper(mapperInterface);
}
}
}
return;
}
}
}
4.Configuration & MapperRegistry
public class Configuration {
protected MapperRegistry mapperRegistry; //存储每个接口的mapper文件对应的类
protected final Map<String, MappedStatement> mappedStatements; //存储由namespace 和sql id 能唯一确定的
sql语句对应的sql节点信息
...
}
public class MapperRegistry {
private Configuration config;
private final Map<Class<?>, MapperProxyFactory<?>> knownMappers = new HashMap();
public MapperRegistry(Configuration config) {
this.config = config;
}
public <T> T getMapper(Class<T> type, SqlSession sqlSession) {
MapperProxyFactory<T> mapperProxyFactory = (MapperProxyFactory)this.knownMappers.get(type);
if (mapperProxyFactory == null) {
throw new BindingException("Type " + type + " is not known to the MapperRegistry.");
} else {
try {
return mapperProxyFactory.newInstance(sqlSession);
} catch (Exception var5) {
throw new BindingException("Error getting mapper instance. Cause: " + var5, var5);
}
}
}
public <T> boolean hasMapper(Class<T> type) {
return this.knownMappers.containsKey(type);
}
public <T> void addMapper(Class<T> type) {
if (type.isInterface()) {
if (this.hasMapper(type)) {
throw new BindingException("Type " + type + " is already known to the MapperRegistry.");
}
boolean loadCompleted = false;
try {
this.knownMappers.put(type, new MapperProxyFactory(type));
MapperAnnotationBuilder parser = new MapperAnnotationBuilder(this.config, type);
parser.parse();
loadCompleted = true;
} finally {
if (!loadCompleted) {
this.knownMappers.remove(type);
}
}
}
}
}
5.建造者模式
一个对象的参数太过于复杂，就不再适于通过构造函数的方式创建对象，而通过建造者模式对该对象的每个参数分别组建
6.DefaultSqlSession和DefaultSqlSessionFactory
private SqlSession openSessionFromDataSource(ExecutorType execType, TransactionIsolationLevel level, boolean autoCommit) {
Transaction tx = null;
DefaultSqlSession var8;
try {
Environment environment = this.configuration.getEnvironment();
TransactionFactory transactionFactory = this.getTransactionFactoryFromEnvironment(environment);
tx = transactionFactory.newTransaction(environment.getDataSource(), level, autoCommit);
Executor executor = this.configuration.newExecutor(tx, execType, autoCommit);
var8 = new DefaultSqlSession(this.configuration, executor);
} catch (Exception var12) {
this.closeTransaction(tx);
throw ExceptionFactory.wrapException("Error opening session. Cause: " + var12, var12);
} finally {
ErrorContext.instance().reset();
}
return var8;
}