Mysql JDBC驱动源码分析(socket的连接创建)三

zhendeaini123

　　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());
}
}