Mysql JDBC驱动源码分析(socket的连接创建)三

Socket的连接创建

代码往下调试进入ConnectionImp下的createNewIO()方法

 

public synchronized void createNewIO(boolean isForReconnect)
			throws SQLException {

		Properties mergedProps  = exposeAsProperties(this.props);

		if (!getHighAvailability()) {
                        //进入该方法
			connectOneTryOnly(isForReconnect, mergedProps);
			
			return;
		} 
                      //???
		connectWithRetries(isForReconnect, mergedProps);
		
	}

 private void connectOneTryOnly(boolean isForReconnect,

			Properties mergedProps) throws SQLException {
		Exception connectionNotEstablishedBecause = null;

		try {
			//IO创建主要在这个方法里
			coreConnect(mergedProps);
			this.connectionId = this.io.getThreadId();
			this.isClosed = false;

			// save state from old connection
			boolean oldAutoCommit = getAutoCommit();
			int oldIsolationLevel = this.isolationLevel;
			boolean oldReadOnly = isReadOnly();
			String oldCatalog = getCatalog();

			this.io.setStatementInterceptors(this.statementInterceptors);
			
			// Server properties might be different
			// from previous connection, so initialize
			// again...
			initializePropsFromServer();

			if (isForReconnect) {
				// Restore state from old connection
				setAutoCommit(oldAutoCommit);

				if (this.hasIsolationLevels) {
					setTransactionIsolation(oldIsolationLevel);
				}

				setCatalog(oldCatalog);
				
				setReadOnly(oldReadOnly);
			}
			return;
			
		} catch (Exception EEE) {
			if (this.io != null) {
				this.io.forceClose();
			}

			connectionNotEstablishedBecause = EEE;

			if (EEE instanceof SQLException) {
				throw (SQLException)EEE;
			}
			
			SQLException chainedEx = SQLError.createSQLException(
					Messages.getString("Connection.UnableToConnect"),
					SQLError.SQL_STATE_UNABLE_TO_CONNECT_TO_DATASOURCE, getExceptionInterceptor());
			chainedEx.initCause(connectionNotEstablishedBecause);
			
			throw chainedEx;
		}
	}

 进入coreconnect()方法

 

private void coreConnect(Properties mergedProps) throws SQLException,
			IOException {
		int newPort = 3306;
		String newHost = "localhost";
		
		String protocol = mergedProps.getProperty(NonRegisteringDriver.PROTOCOL_PROPERTY_KEY);
		
		if (protocol != null) {
			// "new" style URL

			if ("tcp".equalsIgnoreCase(protocol)) {
				newHost = normalizeHost(mergedProps.getProperty(NonRegisteringDriver.HOST_PROPERTY_KEY));
				newPort = parsePortNumber(mergedProps.getProperty(NonRegisteringDriver.PORT_PROPERTY_KEY, "3306"));
			} else if ("pipe".equalsIgnoreCase(protocol)) {
				setSocketFactoryClassName(NamedPipeSocketFactory.class.getName());
				
				String path = mergedProps.getProperty(NonRegisteringDriver.PATH_PROPERTY_KEY);
				
				if (path != null) {
					mergedProps.setProperty(NamedPipeSocketFactory.NAMED_PIPE_PROP_NAME, path);
				}
			} else {
				// normalize for all unknown protocols
				newHost = normalizeHost(mergedProps.getProperty(NonRegisteringDriver.HOST_PROPERTY_KEY));
				newPort = parsePortNumber(mergedProps.getProperty(NonRegisteringDriver.PORT_PROPERTY_KEY, "3306"));
			}
		} else {
		
			String[] parsedHostPortPair = NonRegisteringDriver
					.parseHostPortPair(this.hostPortPair);
			newHost = parsedHostPortPair[NonRegisteringDriver.HOST_NAME_INDEX];

			newHost = normalizeHost(newHost);

			if (parsedHostPortPair[NonRegisteringDriver.PORT_NUMBER_INDEX] != null) {
				newPort = parsePortNumber(parsedHostPortPair[NonRegisteringDriver.PORT_NUMBER_INDEX]);
			}
		}

		this.port = newPort;
		this.host = newHost;
		
              //MysqlIO的创建，用来于服务器进行通信
		this.io = new MysqlIO(newHost, newPort,
				mergedProps, getSocketFactoryClassName(),
				getProxy(), getSocketTimeout(),
				this.largeRowSizeThreshold.getValueAsInt());

     

		this.io.doHandshake(this.user, this.password,
				this.database);
	}

 MysqlIO构造器的创建

 

 public MysqlIO(String host, int port, Properties props,
        String socketFactoryClassName, MySQLConnection conn,
        int socketTimeout, int useBufferRowSizeThreshold) throws IOException, SQLException {
        this.connection = conn;
        
        if (this.connection.getEnablePacketDebug()) {
            this.packetDebugRingBuffer = new LinkedList();
        }
        this.traceProtocol = this.connection.getTraceProtocol();
        

        this.useAutoSlowLog = this.connection.getAutoSlowLog();
        
        this.useBufferRowSizeThreshold = useBufferRowSizeThreshold;
        this.useDirectRowUnpack = this.connection.getUseDirectRowUnpack();

        this.logSlowQueries = this.connection.getLogSlowQueries();

        this.reusablePacket = new Buffer(INITIAL_PACKET_SIZE);
        this.sendPacket = new Buffer(INITIAL_PACKET_SIZE);

        this.port = port;
        this.host = host;

        this.socketFactoryClassName = socketFactoryClassName;
        this.socketFactory = createSocketFactory();
        this.exceptionInterceptor = this.connection.getExceptionInterceptor();
        
        try {//创建得到一个socket
        	this.mysqlConnection = this.socketFactory.connect(this.host,
        		this.port, props);
	        
	
	        if (socketTimeout != 0) {
	        	try {
	        		this.mysqlConnection.setSoTimeout(socketTimeout);
	        	} catch (Exception ex) {
	        		/* Ignore if the platform does not support it */
	        	}
	        }
	
	        this.mysqlConnection = this.socketFactory.beforeHandshake();
	
	        if (this.connection.getUseReadAheadInput()) {
              //创建input流
	        	this.mysqlInput = new ReadAheadInputStream(this.mysqlConnection.getInputStream(), 16384,
	        			this.connection.getTraceProtocol(),
	        			this.connection.getLog());
	        } else if (this.connection.useUnbufferedInput()) {
	        	this.mysqlInput = this.mysqlConnection.getInputStream();
	        } else {
	        	this.mysqlInput = new BufferedInputStream(this.mysqlConnection.getInputStream(),
	        			16384);
	        }
	      //创建output流
	        this.mysqlOutput = new BufferedOutputStream(this.mysqlConnection.getOutputStream(),
	        		16384);
	
	
	        this.isInteractiveClient = this.connection.getInteractiveClient();
	        this.profileSql = this.connection.getProfileSql();
	        this.autoGenerateTestcaseScript = this.connection.getAutoGenerateTestcaseScript();
	
	        this.needToGrabQueryFromPacket = (this.profileSql ||
	        		this.logSlowQueries ||
	        		this.autoGenerateTestcaseScript);
	
	        if (this.connection.getUseNanosForElapsedTime()
					&& Util.nanoTimeAvailable()) {
				this.useNanosForElapsedTime = true;
	
				this.queryTimingUnits = Messages.getString("Nanoseconds");
			} else {
				this.queryTimingUnits = Messages.getString("Milliseconds");
			}
	
			if (this.connection.getLogSlowQueries()) {
				calculateSlowQueryThreshold();
			}
        } catch (IOException ioEx) {
        	throw SQLError.createCommunicationsException(this.connection, 0, 0, ioEx, getExceptionInterceptor());
        }
    }