Hibernate源码分析

protected void reset() {
		classes = new HashMap();
		imports = new HashMap();
		collections = new HashMap();
		tables = new TreeMap();
		namedQueries = new HashMap();
		namedSqlQueries = new HashMap();
		sqlResultSetMappings = new HashMap();
		xmlHelper = new XMLHelper();
		typeDefs = new HashMap();
		propertyReferences = new ArrayList();
		secondPasses = new ArrayList();
		interceptor = EmptyInterceptor.INSTANCE;
		properties = Environment.getProperties();   // 呵呵，就是这一句很重要。
		entityResolver = XMLHelper.DEFAULT_DTD_RESOLVER;
		eventListeners = new EventListeners();
		filterDefinitions = new HashMap();
//		extendsQueue = new ArrayList();
		extendsQueue = new HashMap();
		auxiliaryDatabaseObjects = new ArrayList();
		tableNameBinding = new HashMap();
		columnNameBindingPerTable = new HashMap();
		namingStrategy = DefaultNamingStrategy.INSTANCE;
		sqlFunctions = new HashMap();

		entityTuplizerFactory = new EntityTuplizerFactory();
//		componentTuplizerFactory = new ComponentTuplizerFactory();
	}

static {

		log.info("Hibernate " + VERSION);

		RENAMED_PROPERTIES.put( "hibernate.cglib.use_reflection_optimizer", USE_REFLECTION_OPTIMIZER );

		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_NONE), "NONE" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_READ_UNCOMMITTED), "READ_UNCOMMITTED" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_READ_COMMITTED), "READ_COMMITTED" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_REPEATABLE_READ), "REPEATABLE_READ" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_SERIALIZABLE), "SERIALIZABLE" );

		GLOBAL_PROPERTIES = new Properties();
		//Set USE_REFLECTION_OPTIMIZER to false to fix HHH-227
		GLOBAL_PROPERTIES.setProperty( USE_REFLECTION_OPTIMIZER, Boolean.FALSE.toString() );

		try {
			InputStream stream = ConfigHelper.getResourceAsStream("/hibernate.properties");
			try {
				GLOBAL_PROPERTIES.load(stream);
				log.info( "loaded properties from resource hibernate.properties: " + PropertiesHelper.maskOut(GLOBAL_PROPERTIES, PASS) );
			}
			catch (Exception e) {
				log.error("problem loading properties from hibernate.properties");
			}
			finally {
				try{
					stream.close();
				}
				catch (IOException ioe){
					log.error("could not close stream on hibernate.properties", ioe);
				}
			}
		}
		catch (HibernateException he) {
			log.info("hibernate.properties not found");
		}

		try {
			GLOBAL_PROPERTIES.putAll( System.getProperties() );
		}
		catch (SecurityException se) {
			log.warn("could not copy system properties, system properties will be ignored");
		}

		verifyProperties(GLOBAL_PROPERTIES);

		ENABLE_BINARY_STREAMS = PropertiesHelper.getBoolean(USE_STREAMS_FOR_BINARY, GLOBAL_PROPERTIES);
		ENABLE_REFLECTION_OPTIMIZER = PropertiesHelper.getBoolean(USE_REFLECTION_OPTIMIZER, GLOBAL_PROPERTIES);

		if (ENABLE_BINARY_STREAMS) {
			log.info("using java.io streams to persist binary types");
		}
		if (ENABLE_REFLECTION_OPTIMIZER) {
			log.info("using bytecode reflection optimizer");
		}
		BYTECODE_PROVIDER_INSTANCE = buildBytecodeProvider( GLOBAL_PROPERTIES );

		boolean getGeneratedKeysSupport;
		try {
			Statement.class.getMethod("getGeneratedKeys", null);
			getGeneratedKeysSupport = true;
		}
		catch (NoSuchMethodException nsme) {
			getGeneratedKeysSupport = false;
		}
		JVM_SUPPORTS_GET_GENERATED_KEYS = getGeneratedKeysSupport;
		if (!JVM_SUPPORTS_GET_GENERATED_KEYS) {
			log.info("JVM does not support Statement.getGeneratedKeys()");
		}

		boolean linkedHashSupport;
		try {
			Class.forName("java.util.LinkedHashSet");
			linkedHashSupport = true;
		}
		catch (ClassNotFoundException cnfe) {
			linkedHashSupport = false;
		}
		JVM_SUPPORTS_LINKED_HASH_COLLECTIONS = linkedHashSupport;
		if (!JVM_SUPPORTS_LINKED_HASH_COLLECTIONS) {
			log.info("JVM does not support LinkedHasMap, LinkedHashSet - ordered maps and sets disabled");
		}

		long x = 123456789;
		JVM_HAS_TIMESTAMP_BUG = new Timestamp(x).getTime() != x;
		if (JVM_HAS_TIMESTAMP_BUG) {
			log.info("using workaround for JVM bug in java.sql.Timestamp");
		}

		Timestamp t = new Timestamp(0);
		t.setNanos(5 * 1000000);
		JVM_HAS_JDK14_TIMESTAMP = t.getTime() == 5;
		if (JVM_HAS_JDK14_TIMESTAMP) {
			log.info("using JDK 1.4 java.sql.Timestamp handling");
		}
		else {
			log.info("using pre JDK 1.4 java.sql.Timestamp handling");
		}
	}

Hibernate源码分析

原文：http://hnzmdpan.iteye.com/blog/2291403