com.github.datalking.jdbc.datasource.DataSourceUtils Maven / Gradle / Ivy
package com.github.datalking.jdbc.datasource;
import com.github.datalking.jdbc.transaction.TransactionDefinition;
import com.github.datalking.jdbc.transaction.TransactionSynchronizationAdapter;
import com.github.datalking.jdbc.transaction.TransactionSynchronizationManager;
import com.github.datalking.util.Assert;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
/**
* 数据库DataSource操作 工具类
*/
public abstract class DataSourceUtils {
public static final int CONNECTION_SYNCHRONIZATION_ORDER = 1000;
private static final Logger logger = LoggerFactory.getLogger(DataSourceUtils.class);
public static Connection getConnection(DataSource dataSource) throws Exception {
try {
return doGetConnection(dataSource);
} catch (SQLException ex) {
throw new Exception("Could not get JDBC Connection", ex);
}
}
public static Connection doGetConnection(DataSource dataSource) throws SQLException {
Assert.notNull(dataSource, "No DataSource specified");
ConnectionHolder conHolder = (ConnectionHolder) TransactionSynchronizationManager.getResource(dataSource);
if (conHolder != null && (conHolder.hasConnection() || conHolder.isSynchronizedWithTransaction())) {
conHolder.requested();
if (!conHolder.hasConnection()) {
logger.debug("Fetching resumed JDBC Connection from DataSource");
conHolder.setConnection(dataSource.getConnection());
}
return conHolder.getConnection();
}
// Else we either got no holder or an empty thread-bound holder here.
logger.debug("Fetching JDBC Connection from DataSource");
Connection con = dataSource.getConnection();
if (TransactionSynchronizationManager.isSynchronizationActive()) {
logger.debug("Registering transaction synchronization for JDBC Connection");
// Use same Connection for further JDBC actions within the transaction.
// Thread-bound object will get removed by synchronization at transaction completion.
ConnectionHolder holderToUse = conHolder;
if (holderToUse == null) {
holderToUse = new ConnectionHolder(con);
} else {
holderToUse.setConnection(con);
}
holderToUse.requested();
TransactionSynchronizationManager.registerSynchronization(
new ConnectionSynchronization(holderToUse, dataSource));
holderToUse.setSynchronizedWithTransaction(true);
if (holderToUse != conHolder) {
TransactionSynchronizationManager.bindResource(dataSource, holderToUse);
}
}
return con;
}
/**
* Prepare the given Connection with the given transaction semantics.
*
* @param con the Connection to prepare
* @param definition the transaction definition to apply
* @return the previous isolation level, if any
* @throws SQLException if thrown by JDBC methods
* @see #resetConnectionAfterTransaction
*/
public static Integer prepareConnectionForTransaction(Connection con, TransactionDefinition definition)
throws SQLException {
Assert.notNull(con, "No Connection specified");
// Set read-only flag.
if (definition != null && definition.isReadOnly()) {
try {
if (logger.isDebugEnabled()) {
logger.debug("Setting JDBC Connection [" + con + "] read-only");
}
con.setReadOnly(true);
} catch (SQLException ex) {
Throwable exToCheck = ex;
while (exToCheck != null) {
if (exToCheck.getClass().getSimpleName().contains("Timeout")) {
// Assume it's a connection timeout that would otherwise get lost: e.g. from JDBC 4.0
throw ex;
}
exToCheck = exToCheck.getCause();
}
// "read-only not supported" SQLException -> ignore, it's just a hint anyway
logger.debug("Could not set JDBC Connection read-only", ex);
} catch (RuntimeException ex) {
Throwable exToCheck = ex;
while (exToCheck != null) {
if (exToCheck.getClass().getSimpleName().contains("Timeout")) {
// Assume it's a connection timeout that would otherwise get lost: e.g. from Hibernate
throw ex;
}
exToCheck = exToCheck.getCause();
}
// "read-only not supported" UnsupportedOperationException -> ignore, it's just a hint anyway
logger.debug("Could not set JDBC Connection read-only", ex);
}
}
// Apply specific isolation level, if any.
Integer previousIsolationLevel = null;
if (definition != null && definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT) {
if (logger.isDebugEnabled()) {
logger.debug("Changing isolation level of JDBC Connection [" + con + "] to " +
definition.getIsolationLevel());
}
int currentIsolation = con.getTransactionIsolation();
if (currentIsolation != definition.getIsolationLevel()) {
previousIsolationLevel = currentIsolation;
con.setTransactionIsolation(definition.getIsolationLevel());
}
}
return previousIsolationLevel;
}
/**
* Reset the given Connection after a transaction,
* regarding read-only flag and isolation level.
*
* @param con the Connection to reset
* @param previousIsolationLevel the isolation level to restore, if any
* @see #prepareConnectionForTransaction
*/
public static void resetConnectionAfterTransaction(Connection con, Integer previousIsolationLevel) {
Assert.notNull(con, "No Connection specified");
try {
// Reset transaction isolation to previous value, if changed for the transaction.
if (previousIsolationLevel != null) {
if (logger.isDebugEnabled()) {
logger.debug("Resetting isolation level of JDBC Connection [" +
con + "] to " + previousIsolationLevel);
}
con.setTransactionIsolation(previousIsolationLevel);
}
// Reset read-only flag.
if (con.isReadOnly()) {
if (logger.isDebugEnabled()) {
logger.debug("Resetting read-only flag of JDBC Connection [" + con + "]");
}
con.setReadOnly(false);
}
} catch (Throwable ex) {
logger.debug("Could not reset JDBC Connection after transaction", ex);
}
}
/**
* Determine whether the given JDBC Connection is transactional, that is,
* bound to the current thread by Spring's transaction facilities.
*
* @param con the Connection to check
* @param dataSource the DataSource that the Connection was obtained from
* (may be {@code null})
* @return whether the Connection is transactional
*/
public static boolean isConnectionTransactional(Connection con, DataSource dataSource) {
if (dataSource == null) {
return false;
}
ConnectionHolder conHolder = (ConnectionHolder) TransactionSynchronizationManager.getResource(dataSource);
return (conHolder != null && connectionEquals(conHolder, con));
}
/**
* Apply the current transaction timeout, if any,
* to the given JDBC Statement object.
*
* @param stmt the JDBC Statement object
* @param dataSource the DataSource that the Connection was obtained from
* @throws SQLException if thrown by JDBC methods
* @see Statement#setQueryTimeout
*/
public static void applyTransactionTimeout(Statement stmt, DataSource dataSource) throws SQLException {
applyTimeout(stmt, dataSource, 0);
}
/**
* Apply the specified timeout - overridden by the current transaction timeout,
* if any - to the given JDBC Statement object.
*
* @param stmt the JDBC Statement object
* @param dataSource the DataSource that the Connection was obtained from
* @param timeout the timeout to apply (or 0 for no timeout outside of a transaction)
* @throws SQLException if thrown by JDBC methods
* @see Statement#setQueryTimeout
*/
public static void applyTimeout(Statement stmt, DataSource dataSource, int timeout) throws SQLException {
Assert.notNull(stmt, "No Statement specified");
Assert.notNull(dataSource, "No DataSource specified");
ConnectionHolder holder = (ConnectionHolder) TransactionSynchronizationManager.getResource(dataSource);
if (holder != null && holder.hasTimeout()) {
// Remaining transaction timeout overrides specified value.
stmt.setQueryTimeout(holder.getTimeToLiveInSeconds());
} else if (timeout > 0) {
// No current transaction timeout -> apply specified value.
stmt.setQueryTimeout(timeout);
}
}
/**
* Close the given Connection, obtained from the given DataSource,
* if it is not managed externally (that is, not bound to the thread).
*
* @param con the Connection to close if necessary
* (if this is {@code null}, the call will be ignored)
* @param dataSource the DataSource that the Connection was obtained from
* (may be {@code null})
* @see #getConnection
*/
public static void releaseConnection(Connection con, DataSource dataSource) {
try {
doReleaseConnection(con, dataSource);
} catch (SQLException ex) {
logger.debug("Could not close JDBC Connection", ex);
} catch (Throwable ex) {
logger.debug("Unexpected exception on closing JDBC Connection", ex);
}
}
/**
* Actually close the given Connection, obtained from the given DataSource.
* Same as {@link #releaseConnection}, but throwing the original SQLException.
* Directly accessed by TransactionAwareDataSourceProxy
*
* @param con the Connection to close if necessary
* (if this is {@code null}, the call will be ignored)
* @param dataSource the DataSource that the Connection was obtained from
* (may be {@code null})
* @throws SQLException if thrown by JDBC methods
* @see #doGetConnection
*/
public static void doReleaseConnection(Connection con, DataSource dataSource) throws SQLException {
if (con == null) {
return;
}
if (dataSource != null) {
ConnectionHolder conHolder = (ConnectionHolder) TransactionSynchronizationManager.getResource(dataSource);
if (conHolder != null && connectionEquals(conHolder, con)) {
// It's the transactional Connection: Don't close it.
conHolder.released();
return;
}
}
logger.debug("Returning JDBC Connection to DataSource");
doCloseConnection(con, dataSource);
}
/**
* Close the Connection, unless a SmartDataSource doesn't want us to.
*
* @param con the Connection to close if necessary
* @param dataSource the DataSource that the Connection was obtained from
* @throws SQLException if thrown by JDBC methods
* @see Connection#close()
*/
public static void doCloseConnection(Connection con, DataSource dataSource) throws SQLException {
// if (!(dataSource instanceof SmartDataSource) || ((SmartDataSource) dataSource).shouldClose(con)) {
con.close();
// }
}
/**
* Determine whether the given two Connections are equal, asking the target
* Connection in case of a proxy. Used to detect equality even if the
* user passed in a raw target Connection while the held one is a proxy.
*
* @param conHolder the ConnectionHolder for the held Connection (potentially a proxy)
* @param passedInCon the Connection passed-in by the user
* (potentially a target Connection without proxy)
* @return whether the given Connections are equal
* @see #getTargetConnection
*/
private static boolean connectionEquals(ConnectionHolder conHolder, Connection passedInCon) {
if (!conHolder.hasConnection()) {
return false;
}
Connection heldCon = conHolder.getConnection();
// Explicitly check for identity too: for Connection handles that do not implement
// "equals" properly, such as the ones Commons DBCP exposes).
return (heldCon == passedInCon || heldCon.equals(passedInCon) ||
getTargetConnection(heldCon).equals(passedInCon));
}
/**
* Return the innermost target Connection of the given Connection. If the given
* Connection is a proxy, it will be unwrapped until a non-proxy Connection is
* found. Otherwise, the passed-in Connection will be returned as-is.
*
* @param con the Connection proxy to unwrap
* @return the innermost target Connection, or the passed-in one if no proxy
*/
public static Connection getTargetConnection(Connection con) {
Connection conToUse = con;
while (conToUse instanceof ConnectionProxy) {
conToUse = ((ConnectionProxy) conToUse).getTargetConnection();
}
return conToUse;
}
/**
* Determine the connection synchronization order to use for the given
* DataSource. Decreased for every level of nesting that a DataSource
* has, checked through the level of DelegatingDataSource nesting.
*
* @param dataSource the DataSource to check
* @return the connection synchronization order to use
* @see #CONNECTION_SYNCHRONIZATION_ORDER
*/
private static int getConnectionSynchronizationOrder(DataSource dataSource) {
int order = CONNECTION_SYNCHRONIZATION_ORDER;
DataSource currDs = dataSource;
while (currDs instanceof DelegatingDataSource) {
order--;
currDs = ((DelegatingDataSource) currDs).getTargetDataSource();
}
return order;
}
/**
* Callback for resource cleanup at the end of a non-native JDBC transaction
* (e.g. when participating in a JtaTransactionManager transaction).
*/
private static class ConnectionSynchronization extends TransactionSynchronizationAdapter {
private final ConnectionHolder connectionHolder;
private final DataSource dataSource;
private int order;
private boolean holderActive = true;
public ConnectionSynchronization(ConnectionHolder connectionHolder, DataSource dataSource) {
this.connectionHolder = connectionHolder;
this.dataSource = dataSource;
this.order = getConnectionSynchronizationOrder(dataSource);
}
@Override
public int getOrder() {
return this.order;
}
@Override
public void suspend() {
if (this.holderActive) {
TransactionSynchronizationManager.unbindResource(this.dataSource);
if (this.connectionHolder.hasConnection() && !this.connectionHolder.isOpen()) {
// Release Connection on suspend if the application doesn't keep
// a handle to it anymore. We will fetch a fresh Connection if the
// application accesses the ConnectionHolder again after resume,
// assuming that it will participate in the same transaction.
releaseConnection(this.connectionHolder.getConnection(), this.dataSource);
this.connectionHolder.setConnection(null);
}
}
}
@Override
public void resume() {
if (this.holderActive) {
TransactionSynchronizationManager.bindResource(this.dataSource, this.connectionHolder);
}
}
@Override
public void beforeCompletion() {
// Release Connection early if the holder is not open anymore
// (that is, not used by another resource like a Hibernate Session
// that has its own cleanup via transaction synchronization),
// to avoid issues with strict JTA implementations that expect
// the close call before transaction completion.
if (!this.connectionHolder.isOpen()) {
TransactionSynchronizationManager.unbindResource(this.dataSource);
this.holderActive = false;
if (this.connectionHolder.hasConnection()) {
releaseConnection(this.connectionHolder.getConnection(), this.dataSource);
}
}
}
@Override
public void afterCompletion(int status) {
// If we haven't closed the Connection in beforeCompletion,
// close it now. The holder might have been used for other
// cleanup in the meantime, for example by a Hibernate Session.
if (this.holderActive) {
// The thread-bound ConnectionHolder might not be available anymore,
// since afterCompletion might get called from a different thread.
TransactionSynchronizationManager.unbindResourceIfPossible(this.dataSource);
this.holderActive = false;
if (this.connectionHolder.hasConnection()) {
releaseConnection(this.connectionHolder.getConnection(), this.dataSource);
// Reset the ConnectionHolder: It might remain bound to the thread.
this.connectionHolder.setConnection(null);
}
}
this.connectionHolder.reset();
}
}
}