概述
JDBC驱动初始化-Mysql:[url]http://donald-draper.iteye.com/blog/2342010[/url]
JDBC连接的获取：[url]http://donald-draper.iteye.com/blog/2342011[/url]
Mysql负载均衡连接的获取：[url]http://donald-draper.iteye.com/blog/2342089[/url]
Mysql主从复制读写分离连接的获取：[url]http://donald-draper.iteye.com/blog/2342108[/url]
ConnectionImp创建MysqlIO ：[url]http://donald-draper.iteye.com/blog/2342959[/url]
Mysql预编译SQL：[url]http://donald-draper.iteye.com/blog/2342960[/url]
MysqlSQL PreparedStatement的查询:[url]http://donald-draper.iteye.com/blog/2343083[/url]
MySQL ServerPreparedStatement查询：[url]http://donald-draper.iteye.com/blog/2343124[/url]
在前几篇文章中，我们mysqlSql connection的获取，在ConnectionImp构造中有这么一个函数为createNewI，下面我们来看看，这函数做了什么？
创建MysqlIO
protected void createNewIO(boolean isForReconnect)
throws SQLException
{
Object obj = mutex;
JVM INSTR monitorenter ;
Properties mergedProps;
long queriesIssuedFailedOverCopy;
mergedProps = exposeAsProperties(props);
queriesIssuedFailedOverCopy = queriesIssuedFailedOver;
queriesIssuedFailedOver = 0L;
//对于Standyalone Sever情况
if(!getHighAvailability() && !failedOver)
{
boolean connectionGood = false;
Exception connectionNotEstablishedBecause = null;
int hostIndex = 0;
if(getRoundRobinLoadBalance())
hostIndex = getNextRoundRobinHostIndex(getURL(), hostList);
while(hostIndex < hostListSize)
{
if(hostIndex == 0)
hasTriedMasterFlag = true;
try
{
String newHostPortPair = (String)hostList.get(hostIndex);
int newPort = 3306;
String hostPortPair[] = NonRegisteringDriver.parseHostPortPair(newHostPortPair);
String newHost = hostPortPair[0];
if(newHost == null || StringUtils.isEmptyOrWhitespaceOnly(newHost))
newHost = "localhost";
if(hostPortPair[1] != null)
try
{
newPort = Integer.parseInt(hostPortPair[1]);
}
catch(NumberFormatException nfe)
{
throw SQLError.createSQLException("Illegal connection port value '" + hostPortPair[1] + "'", "01S00", getExceptionInterceptor());
}
//创建MysqlIO
io = new MysqlIO(newHost, newPort, mergedProps, getSocketFactoryClassName(), this, getSocketTimeout(), largeRowSizeThreshold.getValueAsInt());
//握手
io.doHandshake(user, password, database);
//获取io的线程id
connectionId = io.getThreadId();
isClosed = false;
boolean oldAutoCommit = getAutoCommit();//AutoCommit
int oldIsolationLevel = isolationLevel;//事务隔离级别
boolean oldReadOnly = isReadOnly();//ReadOnly
String oldCatalog = getCatalog();
initializePropsFromServer();
if(isForReconnect)
{
setAutoCommit(oldAutoCommit);
if(hasIsolationLevels)
setTransactionIsolation(oldIsolationLevel);
setCatalog(oldCatalog);
}
if(hostIndex != 0)
{
setFailedOverState();
queriesIssuedFailedOverCopy = 0L;
} else
{
failedOver = false;
queriesIssuedFailedOverCopy = 0L;
if(hostListSize > 1)
setReadOnlyInternal(false);
else
setReadOnlyInternal(oldReadOnly);
}
connectionGood = true;
break;
}
catch(Exception EEE)
{
if(io != null)
io.forceClose();
connectionNotEstablishedBecause = EEE;
connectionGood = false;
if(EEE instanceof SQLException)
{
SQLException sqlEx = (SQLException)EEE;
String sqlState = sqlEx.getSQLState();
if(sqlState == null || !sqlState.equals("08S01"))
throw sqlEx;
}
if(getRoundRobinLoadBalance())
{
hostIndex = getNextRoundRobinHostIndex(getURL(), hostList) - 1;
continue;
}
if(hostListSize - 1 == hostIndex)
throw SQLError.createCommunicationsException(this, io == null ? 0L : io.getLastPacketSentTimeMs(), io == null ? 0L : io.getLastPacketReceivedTimeMs(), EEE, getExceptionInterceptor());
hostIndex++;
}
}
if(!connectionGood)
{
SQLException chainedEx = SQLError.createSQLException(Messages.getString("Connection.UnableToConnect"), "08001", getExceptionInterceptor());
chainedEx.initCause(connectionNotEstablishedBecause);
throw chainedEx;
}
} else
{
//对于负载均衡集群
double timeout = getInitialTimeout();
boolean connectionGood = false;
Exception connectionException = null;
int hostIndex = 0;
if(getRoundRobinLoadBalance())
hostIndex = getNextRoundRobinHostIndex(getURL(), hostList);
for(; hostIndex < hostListSize && !connectionGood; hostIndex++)
{
if(hostIndex == 0)
hasTriedMasterFlag = true;
if(preferSlaveDuringFailover && hostIndex == 0)
hostIndex++;
for(int attemptCount = 0; attemptCount < getMaxReconnects() && !connectionGood; attemptCount++)
{
try
{
if(io != null)
io.forceClose();
String newHostPortPair = (String)hostList.get(hostIndex);
int newPort = 3306;
String hostPortPair[] = NonRegisteringDriver.parseHostPortPair(newHostPortPair);
String newHost = hostPortPair[0];
if(newHost == null || StringUtils.isEmptyOrWhitespaceOnly(newHost))
newHost = "localhost";
if(hostPortPair[1] != null)
try
{
newPort = Integer.parseInt(hostPortPair[1]);
}
catch(NumberFormatException nfe)
{
throw SQLError.createSQLException("Illegal connection port value '" + hostPortPair[1] + "'", "01S00", getExceptionInterceptor());
}
//创建MysqlIO
io = new MysqlIO(newHost, newPort, mergedProps, getSocketFactoryClassName(), this, getSocketTimeout(), largeRowSizeThreshold.getValueAsInt());
//握手
io.doHandshake(user, password, database);
pingInternal(false, 0);
//获取io的线程id
connectionId = io.getThreadId();
isClosed = false;
boolean oldAutoCommit = getAutoCommit();//AutoCommit
int oldIsolationLevel = isolationLevel;//事务级别
boolean oldReadOnly = isReadOnly();//ReadOnly
String oldCatalog = getCatalog();
initializePropsFromServer();
if(isForReconnect)
{
setAutoCommit(oldAutoCommit);
if(hasIsolationLevels)
setTransactionIsolation(oldIsolationLevel);
setCatalog(oldCatalog);
}
connectionGood = true;
if(hostIndex != 0)
{
setFailedOverState();
queriesIssuedFailedOverCopy = 0L;
break;
}
failedOver = false;
queriesIssuedFailedOverCopy = 0L;
if(hostListSize > 1)
setReadOnlyInternal(false);
else
setReadOnlyInternal(oldReadOnly);
break;
}
catch(Exception EEE)
{
connectionException = EEE;
}
connectionGood = false;
if(getRoundRobinLoadBalance())
hostIndex = getNextRoundRobinHostIndex(getURL(), hostList) - 1;
if(connectionGood)
break;
if(attemptCount <= 0)
continue;
try
{
Thread.sleep((long)timeout * 1000L);
}
catch(InterruptedException IE) { }
}
}
}
}//MysqlIO
class MysqlIO
{
private static final int UTF8_CHARSET_INDEX = 33;
private static final String CODE_PAGE_1252 = "Cp1252";
protected static final int NULL_LENGTH = -1;
protected static final int COMP_HEADER_LENGTH = 3;
protected static final int MIN_COMPRESS_LEN = 50;
protected static final int HEADER_LENGTH = 4;
protected static final int AUTH_411_OVERHEAD = 33;
private static int maxBufferSize = 65535;
private static final int CLIENT_COMPRESS = 32;
protected static final int CLIENT_CONNECT_WITH_DB = 8;
private static final int CLIENT_FOUND_ROWS = 2;
private static final int CLIENT_LOCAL_FILES = 128;
private static final int CLIENT_LONG_FLAG = 4;
private static final int CLIENT_LONG_PASSWORD = 1;
private static final int CLIENT_PROTOCOL_41 = 512;
private static final int CLIENT_INTERACTIVE = 1024;
protected static final int CLIENT_SSL = 2048;
private static final int CLIENT_TRANSACTIONS = 8192;
protected static final int CLIENT_RESERVED = 16384;
protected static final int CLIENT_SECURE_CONNECTION = 32768;
private static final int CLIENT_MULTI_QUERIES = 65536;
private static final int CLIENT_MULTI_RESULTS = 131072;
private static final int SERVER_STATUS_IN_TRANS = 1;
private static final int SERVER_STATUS_AUTOCOMMIT = 2;
static final int SERVER_MORE_RESULTS_EXISTS = 8;
private static final int SERVER_QUERY_NO_GOOD_INDEX_USED = 16;
private static final int SERVER_QUERY_NO_INDEX_USED = 32;
private static final int SERVER_QUERY_WAS_SLOW = 2048;
private static final int SERVER_STATUS_CURSOR_EXISTS = 64;
private static final String FALSE_SCRAMBLE = "xxxxxxxx";
protected static final int MAX_QUERY_SIZE_TO_LOG = 1024;
protected static final int MAX_QUERY_SIZE_TO_EXPLAIN = 1048576;
protected static final int INITIAL_PACKET_SIZE = 1024;
private static String jvmPlatformCharset = null;
protected static final String ZERO_DATE_VALUE_MARKER = "0000-00-00";
protected static final String ZERO_DATETIME_VALUE_MARKER = "0000-00-00 00:00:00";
private static final int MAX_PACKET_DUMP_LENGTH = 1024;
private boolean packetSequenceReset;
protected int serverCharsetIndex;
private Buffer reusablePacket;
private Buffer sendPacket;
private Buffer sharedSendPacket;
protected BufferedOutputStream mysqlOutput;
protected ConnectionImpl connection;//Mysql connection
private Deflater deflater;
protected InputStream mysqlInput;//mysql输入流
private LinkedList packetDebugRingBuffer;
private RowData streamingData;
protected Socket mysqlConnection;//mysql socket
private SocketFactory socketFactory;// mysql socket的工场
private SoftReference loadFileBufRef;
private SoftReference splitBufRef;
protected String host;//host
protected String seed;
private String serverVersion;
private String socketFactoryClassName;
private byte packetHeaderBuf[];
private boolean colDecimalNeedsBump;
private boolean hadWarnings;
private boolean has41NewNewProt;
private boolean hasLongColumnInfo;
private boolean isInteractiveClient;
private boolean logSlowQueries;
private boolean platformDbCharsetMatches;
private boolean profileSql;
private boolean queryBadIndexUsed;
private boolean queryNoIndexUsed;
private boolean serverQueryWasSlow;
private boolean use41Extensions;
private boolean useCompression;
private boolean useNewLargePackets;
private boolean useNewUpdateCounts;
private byte packetSequence;
private byte readPacketSequence;
private boolean checkPacketSequence;
private byte protocolVersion;
private int maxAllowedPacket;
protected int maxThreeBytes;
protected int port;
protected int serverCapabilities;
private int serverMajorVersion;
private int serverMinorVersion;
private int oldServerStatus;
private int serverStatus;
private int serverSubMinorVersion;
private int warningCount;
protected long clientParam;
protected long lastPacketSentTimeMs;
protected long lastPacketReceivedTimeMs;
private boolean traceProtocol;
private boolean enablePacketDebug;
private Calendar sessionCalendar;
private boolean useConnectWithDb;
private boolean needToGrabQueryFromPacket;
private boolean autoGenerateTestcaseScript;
private long threadId;
private boolean useNanosForElapsedTime;
private long slowQueryThreshold;
private String queryTimingUnits;
private boolean useDirectRowUnpack;
private int useBufferRowSizeThreshold;
private int commandCount;
private List statementInterceptors;
private ExceptionInterceptor exceptionInterceptor;
private int statementExecutionDepth;
private boolean useAutoSlowLog;
static
{
OutputStreamWriter outWriter = null;
try
{
outWriter = new OutputStreamWriter(new ByteArrayOutputStream());
jvmPlatformCharset = outWriter.getEncoding();
}
finally
{
try
{
if(outWriter != null)
outWriter.close();
}
catch(IOException ioEx) { }
}
}
//MysqlIO构造
public MysqlIO(String host, int port, Properties props, String socketFactoryClassName, ConnectionImpl conn, int socketTimeout, int useBufferRowSizeThreshold)
throws IOException, SQLException
{
packetSequenceReset = false;
reusablePacket = null;
sendPacket = null;
sharedSendPacket = null;
mysqlOutput = null;
deflater = null;
mysqlInput = null;
packetDebugRingBuffer = null;
streamingData = null;
mysqlConnection = null;
socketFactory = null;
this.host = null;
serverVersion = null;
this.socketFactoryClassName = null;
packetHeaderBuf = new byte[4];
colDecimalNeedsBump = false;
hadWarnings = false;
has41NewNewProt = false;
hasLongColumnInfo = false;
isInteractiveClient = false;
logSlowQueries = false;
platformDbCharsetMatches = true;
profileSql = false;
queryBadIndexUsed = false;
queryNoIndexUsed = false;
serverQueryWasSlow = false;
use41Extensions = false;
useCompression = false;
useNewLargePackets = false;
useNewUpdateCounts = false;
packetSequence = 0;
readPacketSequence = -1;
checkPacketSequence = false;
protocolVersion = 0;
maxAllowedPacket = 1048576;
maxThreeBytes = 16581375;
this.port = 3306;
serverMajorVersion = 0;
serverMinorVersion = 0;
oldServerStatus = 0;
serverStatus = 0;
serverSubMinorVersion = 0;
warningCount = 0;
clientParam = 0L;
lastPacketSentTimeMs = 0L;
lastPacketReceivedTimeMs = 0L;
traceProtocol = false;
enablePacketDebug = false;
useDirectRowUnpack = true;
commandCount = 0;
statementExecutionDepth = 0;
connection = conn;
if(connection.getEnablePacketDebug())
packetDebugRingBuffer = new LinkedList();
traceProtocol = connection.getTraceProtocol();
useAutoSlowLog = connection.getAutoSlowLog();
this.useBufferRowSizeThreshold = useBufferRowSizeThreshold;
useDirectRowUnpack = connection.getUseDirectRowUnpack();
logSlowQueries = connection.getLogSlowQueries();
reusablePacket = new Buffer(1024);
sendPacket = new Buffer(1024);
this.port = port;
this.host = host;
this.socketFactoryClassName = socketFactoryClassName;
//创建socket的工场
socketFactory = createSocketFactory();
exceptionInterceptor = connection.getExceptionInterceptor();
try
{
//从socket的工场获取连接
mysqlConnection = socketFactory.connect(this.host, this.port, props);
if(socketTimeout != 0)
try
{
mysqlConnection.setSoTimeout(socketTimeout);
}
catch(Exception ex) { }
//握手前
mysqlConnection = socketFactory.beforeHandshake();
if(connection.getUseReadAheadInput())
mysqlInput = new ReadAheadInputStream(mysqlConnection.getInputStream(), 16384, connection.getTraceProtocol(), connection.getLog());
else
if(connection.useUnbufferedInput())
//从mysqlConnection获取输入流
mysqlInput = mysqlConnection.getInputStream();
else
mysqlInput = new BufferedInputStream(mysqlConnection.getInputStream(), 16384);
//初始化mysqlOutput输出流
mysqlOutput = new BufferedOutputStream(mysqlConnection.getOutputStream(), 16384);
isInteractiveClient = connection.getInteractiveClient();
profileSql = connection.getProfileSql();
sessionCalendar = Calendar.getInstance();
autoGenerateTestcaseScript = connection.getAutoGenerateTestcaseScript();
needToGrabQueryFromPacket = profileSql || logSlowQueries || autoGenerateTestcaseScript;
if(connection.getUseNanosForElapsedTime() && Util.nanoTimeAvailable())
{
useNanosForElapsedTime = true;
queryTimingUnits = Messages.getString("Nanoseconds");
} else
{
queryTimingUnits = Messages.getString("Milliseconds");
}
if(connection.getLogSlowQueries())
calculateSlowQueryThreshold();
}
catch(IOException ioEx)
{
throw SQLError.createCommunicationsException(connection, 0L, 0L, ioEx, getExceptionInterceptor());
}
}
}//创建socket的工场
socketFactory = createSocketFactory();
private SocketFactory createSocketFactory()
throws SQLException
{
if(socketFactoryClassName == null)
throw SQLError.createSQLException(Messages.getString("MysqlIO.75"), "08001", getExceptionInterceptor());
return (SocketFactory)Class.forName(socketFactoryClassName).newInstance();
Exception ex;
ex;
SQLException sqlEx = SQLError.createSQLException(Messages.getString("MysqlIO.76") + socketFactoryClassName + Messages.getString("MysqlIO.77"), "08001", getExceptionInterceptor());
sqlEx.initCause(ex);
throw sqlEx;
}这个socketFactoryClassName是从何来呢？这个在ConnectionPropertiesImpl中
//ConnectionPropertiesImpl
public class ConnectionPropertiesImpl
implements Serializable, ConnectionProperties
{
public ConnectionPropertiesImpl()
{
//socket的工场类
socketFactoryClassName = new StringConnectionProperty("socketFactory", (com.mysql.jdbc.StandardSocketFactory.class).getName(), Messages.getString("ConnectionProperties.socketFactory"), "3.0.3", CONNECTION_AND_AUTH_CATEGORY, 4);
}
}从ConnectionPropertiesImpl可以看出，socket的工厂类其实为StandardSocketFactory
//从socket的工场获取连接
mysqlConnection = socketFactory.connect(this.host, this.port, props);//StandardSocketFactory
public class StandardSocketFactory
implements SocketFactory
{
public static final String TCP_NO_DELAY_PROPERTY_NAME = "tcpNoDelay";
public static final String TCP_KEEP_ALIVE_DEFAULT_VALUE = "true";
public static final String TCP_KEEP_ALIVE_PROPERTY_NAME = "tcpKeepAlive";
public static final String TCP_RCV_BUF_PROPERTY_NAME = "tcpRcvBuf";
public static final String TCP_SND_BUF_PROPERTY_NAME = "tcpSndBuf";
public static final String TCP_TRAFFIC_CLASS_PROPERTY_NAME = "tcpTrafficClass";
public static final String TCP_RCV_BUF_DEFAULT_VALUE = "0";
public static final String TCP_SND_BUF_DEFAULT_VALUE = "0";
public static final String TCP_TRAFFIC_CLASS_DEFAULT_VALUE = "0";
public static final String TCP_NO_DELAY_DEFAULT_VALUE = "true";
private static Method setTraficClassMethod;
protected String host;
protected int port;
protected Socket rawSocket;
static
{
try
{
setTraficClassMethod = (java.net.Socket.class).getMethod("setTrafficClass", new Class[] {
Integer.TYPE
});
}
catch(SecurityException e)
{
setTraficClassMethod = null;
}
catch(NoSuchMethodException e)
{
setTraficClassMethod = null;
}
}
//socket的工场构造
public StandardSocketFactory()
{
host = null;
port = 3306;
rawSocket = null;
}
//获取socket
public Socket connect(String hostname, int portNumber, Properties props)
throws SocketException, IOException
{
if(props != null)
{
host = hostname;
port = portNumber;
Method connectWithTimeoutMethod = null;
Method socketBindMethod = null;
Class socketAddressClass = null;
String localSocketHostname = props.getProperty("localSocketAddress");
String connectTimeoutStr = props.getProperty("connectTimeout");
int connectTimeout = 0;
boolean wantsTimeout = connectTimeoutStr != null && connectTimeoutStr.length() > 0 && !connectTimeoutStr.equals("0");
boolean wantsLocalBind = localSocketHostname != null && localSocketHostname.length() > 0;
boolean needsConfigurationBeforeConnect = socketNeedsConfigurationBeforeConnect(props);
if(wantsTimeout || wantsLocalBind || needsConfigurationBeforeConnect)
{
if(connectTimeoutStr != null)
try
{
connectTimeout = Integer.parseInt(connectTimeoutStr);
}
catch(NumberFormatException nfe)
{
throw new SocketException("Illegal value '" + connectTimeoutStr + "' for connectTimeout");
}
try
{
socketAddressClass = Class.forName("java.net.SocketAddress");
//获取socket的connect方法
connectWithTimeoutMethod = (java.net.Socket.class).getMethod("connect", new Class[] {
socketAddressClass, Integer.TYPE
});
//获取socket的bing方法
socketBindMethod = (java.net.Socket.class).getMethod("bind", new Class[] {
socketAddressClass
});
}
catch(NoClassDefFoundError noClassDefFound) { }
catch(NoSuchMethodException noSuchMethodEx) { }
catch(Throwable catchAll) { }
if(wantsLocalBind && socketBindMethod == null)
throw new SocketException("Can't specify "localSocketAddress" on JVMs older than 1.4");
if(wantsTimeout && connectWithTimeoutMethod == null)
throw new SocketException("Can't specify "connectTimeout" on JVMs older than 1.4");
}
if(host != null)
{
//当host地址存在，同时不需要本地bind
if(!wantsLocalBind && !wantsTimeout && !needsConfigurationBeforeConnect)
{
InetAddress possibleAddresses[] = InetAddress.getAllByName(host);
Throwable caughtWhileConnecting = null;
int i = 0;
do
{
if(i >= possibleAddresses.length)
break;
try
{
rawSocket = new Socket(possibleAddresses[i], port);
//配置socket
configureSocket(rawSocket, props);
break;
}
catch(Exception ex)
{
caughtWhileConnecting = ex;
i++;
}
} while(true);
if(rawSocket == null)
unwrapExceptionToProperClassAndThrowIt(caughtWhileConnecting);
} else
{
//如果需要本地绑定端口
try
{
InetAddress possibleAddresses[] = InetAddress.getAllByName(host);
Throwable caughtWhileConnecting = null;
Object localSockAddr = null;
Class inetSocketAddressClass = null;
Constructor addrConstructor = null;
try
{
inetSocketAddressClass = Class.forName("java.net.InetSocketAddress");
//获取InetSocketAddress的构造函数
addrConstructor = inetSocketAddressClass.getConstructor(new Class[] {
java.net.InetAddress.class, Integer.TYPE
});
if(wantsLocalBind)
//如果需要绑定端口，构造socket地址
localSockAddr = addrConstructor.newInstance(new Object[] {
InetAddress.getByName(localSocketHostname), new Integer(0)
});
}
catch(Throwable ex)
{
unwrapExceptionToProperClassAndThrowIt(ex);
}
int i = 0;
do
{
if(i >= possibleAddresses.length)
break;
try
{
rawSocket = new Socket();
//配置socket
configureSocket(rawSocket, props);
//创建InetSocketAddress
Object sockAddr = addrConstructor.newInstance(new Object[] {
possibleAddresses[i], new Integer(port)
});
//socket地址绑定
socketBindMethod.invoke(rawSocket, new Object[] {
localSockAddr
});
//连接server
connectWithTimeoutMethod.invoke(rawSocket, new Object[] {
sockAddr, new Integer(connectTimeout)
});
break;
}
catch(Exception ex)
{
rawSocket = null;
caughtWhileConnecting = ex;
i++;
}
} while(true);
if(rawSocket == null)
unwrapExceptionToProperClassAndThrowIt(caughtWhileConnecting);
}
catch(Throwable t)
{
unwrapExceptionToProperClassAndThrowIt(t);
}
}
return rawSocket;
}
}
throw new SocketException("Unable to create socket");
}
//配置socket
private void configureSocket(Socket sock, Properties props)
throws SocketException, IOException
{
try
{
//设置Tcp无延时属性
sock.setTcpNoDelay(Boolean.valueOf(props.getProperty("tcpNoDelay", "true")).booleanValue());
String keepAlive = props.getProperty("tcpKeepAlive", "true");
if(keepAlive != null && keepAlive.length() > 0)
//设置是否心跳检查
sock.setKeepAlive(Boolean.valueOf(keepAlive).booleanValue());
int receiveBufferSize = Integer.parseInt(props.getProperty("tcpRcvBuf", "0"));
if(receiveBufferSize > 0)
//设置接收缓冲区大小
sock.setReceiveBufferSize(receiveBufferSize);
int sendBufferSize = Integer.parseInt(props.getProperty("tcpSndBuf", "0"));
if(sendBufferSize > 0)
//设置发送缓冲区大小
sock.setSendBufferSize(sendBufferSize);
int trafficClass = Integer.parseInt(props.getProperty("tcpTrafficClass", "0"));
if(trafficClass > 0 && setTraficClassMethod != null)
//冲突解决
setTraficClassMethod.invoke(sock, new Object[] {
new Integer(trafficClass)
});
}
catch(Throwable t)
{
unwrapExceptionToProperClassAndThrowIt(t);
}
}
}//握手前
mysqlConnection = socketFactory.beforeHandshake();
//StandardSocketFactory
//返回初始化socket
public Socket beforeHandshake()
throws SocketException, IOException
{
return rawSocket;
}//握手后
public Socket afterHandshake()
throws SocketException, IOException
{
return rawSocket;
}从上面可以看出，createNewIO主要所做的工作就是初始化MysqlIO，在构造MysqlIO时，首先
创建socket的工场类，实际为StandardSocketFactory，并从StandardSocketFactory获取socket的连接，同时初始化MysqlIO的输入流与输出流，MysqlIO在Statement执行时，将sql命令发送到
Server。
//MysqlIO握手
void doHandshake(String user, String password, String database)
throws SQLException
{
checkPacketSequence = false;
readPacketSequence = 0;
Buffer buf = readPacket();
protocolVersion = buf.readByte();
if(protocolVersion == -1)
{
try
{
mysqlConnection.close();
}
catch(Exception e) { }
int errno = 2000;
errno = buf.readInt();
String serverErrorMessage = buf.readString("ASCII", getExceptionInterceptor());
StringBuffer errorBuf = new StringBuffer(Messages.getString("MysqlIO.10"));
errorBuf.append(serverErrorMessage);
errorBuf.append(""");
String xOpen = SQLError.mysqlToSqlState(errno, connection.getUseSqlStateCodes());
throw SQLError.createSQLException(SQLError.get(xOpen) + ", " + errorBuf.toString(), xOpen, errno, getExceptionInterceptor());
}
//版本信息
serverVersion = buf.readString("ASCII", getExceptionInterceptor());
int point = serverVersion.indexOf('.');
if(point != -1)
{
try
{
int n = Integer.parseInt(serverVersion.substring(0, point));
serverMajorVersion = n;
}
catch(NumberFormatException NFE1) { }
String remaining = serverVersion.substring(point + 1, serverVersion.length());
point = remaining.indexOf('.');
if(point != -1)
{
try
{
int n = Integer.parseInt(remaining.substring(0, point));
serverMinorVersion = n;
}
catch(NumberFormatException nfe) { }
remaining = remaining.substring(point + 1, remaining.length());
int pos;
for(pos = 0; pos < remaining.length() && remaining.charAt(pos) >= '0' && remaining.charAt(pos) <= '9'; pos++);
try
{
int n = Integer.parseInt(remaining.substring(0, pos));
serverSubMinorVersion = n;
}
catch(NumberFormatException nfe) { }
}
}
if(versionMeetsMinimum(4, 0, 8))
{
maxThreeBytes = 16777215;
useNewLargePackets = true;
} else
{
maxThreeBytes = 16581375;
useNewLargePackets = false;
}
colDecimalNeedsBump = versionMeetsMinimum(3, 23, 0);
colDecimalNeedsBump = !versionMeetsMinimum(3, 23, 15);
useNewUpdateCounts = versionMeetsMinimum(3, 22, 5);
threadId = buf.readLong();
seed = buf.readString("ASCII", getExceptionInterceptor());
serverCapabilities = 0;
if(buf.getPosition() < buf.getBufLength())
serverCapabilities = buf.readInt();
if(versionMeetsMinimum(4, 1, 1))
{
int position = buf.getPosition();
serverCharsetIndex = buf.readByte() & 255;
serverStatus = buf.readInt();
checkTransactionState(0);
buf.setPosition(position + 16);
String seedPart2 = buf.readString("ASCII", getExceptionInterceptor());
StringBuffer newSeed = new StringBuffer(20);
newSeed.append(seed);
newSeed.append(seedPart2);
seed = newSeed.toString();
}
if((serverCapabilities & 32) != 0 && connection.getUseCompression())
clientParam |= 32L;
//DB信息
useConnectWithDb = database != null && database.length() > 0 && !connection.getCreateDatabaseIfNotExist();
if(useConnectWithDb)
clientParam |= 8L;
if((serverCapabilities & 2048) == 0 && connection.getUseSSL())
{
if(connection.getRequireSSL())
{
connection.close();
forceClose();
throw SQLError.createSQLException(Messages.getString("MysqlIO.15"), "08001", getExceptionInterceptor());
}
connection.setUseSSL(false);
}
if((serverCapabilities & 4) != 0)
{
clientParam |= 4L;
hasLongColumnInfo = true;
}
if(!connection.getUseAffectedRows())
clientParam |= 2L;
if(connection.getAllowLoadLocalInfile())
clientParam |= 128L;
if(isInteractiveClient)
clientParam |= 1024L;
if(protocolVersion > 9)
clientParam |= 1L;
else
clientParam &= -2L;
if(versionMeetsMinimum(4, 1, 0))
{
if(versionMeetsMinimum(4, 1, 1))
{
clientParam |= 512L;
has41NewNewProt = true;
clientParam |= 8192L;
clientParam |= 131072L;
if(connection.getAllowMultiQueries())
clientParam |= 65536L;
} else
{
clientParam |= 16384L;
has41NewNewProt = false;
}
use41Extensions = true;
}
int passwordLength = 16;
int userLength = user == null ? 0 : user.length();
int databaseLength = database == null ? 0 : database.length();
int packLength = (userLength + passwordLength + databaseLength) * 2 + 7 + 4 + 33;
Buffer packet = null;
//SSL
if(!connection.getUseSSL())
{
if((serverCapabilities & 32768) != 0)
{
clientParam |= 32768L;
//安全验证
if(versionMeetsMinimum(4, 1, 1))
secureAuth411(null, packLength, user, password, database, true);
else
secureAuth(null, packLength, user, password, database, true);
} else
{
packet = new Buffer(packLength);
if((clientParam & 16384L) != 0L)
{
if(versionMeetsMinimum(4, 1, 1))
{
packet.writeLong(clientParam);
packet.writeLong(maxThreeBytes);
packet.writeByte((byte)8);
packet.writeBytesNoNull(new byte[23]);
} else
{
packet.writeLong(clientParam);
packet.writeLong(maxThreeBytes);
}
} else
{
packet.writeInt((int)clientParam);
packet.writeLongInt(maxThreeBytes);
}
packet.writeString(user, "Cp1252", connection);
if(protocolVersion > 9)
packet.writeString(Util.newCrypt(password, seed), "Cp1252", connection);
else
packet.writeString(Util.oldCrypt(password, seed), "Cp1252", connection);
if(useConnectWithDb)
packet.writeString(database, "Cp1252", connection);
send(packet, packet.getPosition());
}
} else
{
//无SSL连接
negotiateSSLConnection(user, password, database, packLength);
}
if(!versionMeetsMinimum(4, 1, 1))
checkErrorPacket();
if((serverCapabilities & 32) != 0 && connection.getUseCompression())
{
deflater = new Deflater();
useCompression = true;
mysqlInput = new CompressedInputStream(connection, mysqlInput);
}
if(!useConnectWithDb)
changeDatabaseTo(database);
try
{
//握手完毕
mysqlConnection = socketFactory.afterHandshake();
}
catch(IOException ioEx)
{
throw SQLError.createCommunicationsException(connection, lastPacketSentTimeMs, lastPacketReceivedTimeMs, ioEx, getExceptionInterceptor());
}
}
//无SSL连接
private void negotiateSSLConnection(String user, String password, String database, int packLength)
throws SQLException
{
if(!ExportControlled.enabled())
throw new ConnectionFeatureNotAvailableException(connection, lastPacketSentTimeMs, null);
boolean doSecureAuth = false;
if((serverCapabilities & 32768) != 0)
{
clientParam |= 32768L;
doSecureAuth = true;
}
clientParam |= 2048L;
Buffer packet = new Buffer(packLength);
if(use41Extensions)
packet.writeLong(clientParam);
else
packet.writeInt((int)clientParam);
send(packet, packet.getPosition());
ExportControlled.transformSocketToSSLSocket(this);
packet.clear();
if(doSecureAuth)
{
if(versionMeetsMinimum(4, 1, 1))
secureAuth411(null, packLength, user, password, database, true);
else
secureAuth411(null, packLength, user, password, database, true);
} else
{
if(use41Extensions)
{
packet.writeLong(clientParam);
packet.writeLong(maxThreeBytes);
} else
{
packet.writeInt((int)clientParam);
packet.writeLongInt(maxThreeBytes);
}
packet.writeString(user);
if(protocolVersion > 9)
packet.writeString(Util.newCrypt(password, seed));
else
packet.writeString(Util.oldCrypt(password, seed));
if((serverCapabilities & 8) != 0 && database != null && database.length() > 0)
packet.writeString(database);
//发送数据包
send(packet, packet.getPosition());
}
}
//发送sql Packet
private final void sendSplitPackets(Buffer packet)
throws SQLException
{
try
{
Buffer headerPacket = splitBufRef != null ? (Buffer)splitBufRef.get() : null;
if(headerPacket == null)
{
headerPacket = new Buffer(maxThreeBytes + 4);
splitBufRef = new SoftReference(headerPacket);
}
int len = packet.getPosition();
int splitSize = maxThreeBytes;
int originalPacketPos = 4;
byte origPacketBytes[] = packet.getByteBuffer();
byte headerPacketBytes[] = headerPacket.getByteBuffer();
int packetLen;
for(; len >= maxThreeBytes; len -= splitSize)
{
packetSequence++;
headerPacket.setPosition(0);
headerPacket.writeLongInt(splitSize);
headerPacket.writeByte(packetSequence);
System.arraycopy(origPacketBytes, originalPacketPos, headerPacketBytes, 4, splitSize);
packetLen = splitSize + 4;
if(!useCompression)
{
mysqlOutput.write(headerPacketBytes, 0, splitSize + 4);
mysqlOutput.flush();
} else
{
headerPacket.setPosition(0);
Buffer packetToSend = compressPacket(headerPacket, 4, splitSize, 4);
packetLen = packetToSend.getPosition();
mysqlOutput.write(packetToSend.getByteBuffer(), 0, packetLen);
mysqlOutput.flush();
}
originalPacketPos += splitSize;
}
headerPacket.clear();
headerPacket.setPosition(0);
headerPacket.writeLongInt(len - 4);
packetSequence++;
headerPacket.writeByte(packetSequence);
if(len != 0)
System.arraycopy(origPacketBytes, originalPacketPos, headerPacketBytes, 4, len - 4);
packetLen = len - 4;
if(!useCompression)
{
//将数据包写入输出流
protected BufferedOutputStream mysqlOutput;
mysqlOutput.write(headerPacket.getByteBuffer(), 0, len);
mysqlOutput.flush();
} else
{
headerPacket.setPosition(0);
Buffer packetToSend = compressPacket(headerPacket, 4, packetLen, 4);
packetLen = packetToSend.getPosition();
mysqlOutput.write(packetToSend.getByteBuffer(), 0, packetLen);
mysqlOutput.flush();
}
}
catch(IOException ioEx)
{
throw SQLError.createCommunicationsException(connection, lastPacketSentTimeMs, lastPacketReceivedTimeMs, ioEx, getExceptionInterceptor());
}
}MysqlIO握手，主要做的工作是，发送用户，密码，数据库等信息。
总结：
[color=blue]createNewIO主要所做的工作就是初始化MysqlIO，在构造MysqlIO时，首先创建socket的工场类，实际为StandardSocketFactory，并从StandardSocketFactory获取socket的连接，同时初始化MysqlIO的输入流与输出流，MysqlIO在Statement执行时，将sql命令发送到[/color]
Server。MysqlIO握手，主要做的工作是，发送用户，密码，数据库等信息。
最后
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