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Retry DatabaseMetaData retrieval if access to transactional connection fails

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Closes gh-25681
This commit is contained in:
Juergen Hoeller
2020-09-03 23:21:56 +02:00
parent a577f633ff
commit eec4a6d521
1 changed files with 27 additions and 13 deletions
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40
spring-jdbc/src/main/java/org/springframework/jdbc/support/JdbcUtils.java
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@@ -1,5 +1,5 @@
/*
* Copyright 2002-2018 the original author or authors.
* Copyright 2002-2020 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -305,18 +305,19 @@ public abstract class JdbcUtils {
/**
* Extract database meta-data via the given DatabaseMetaDataCallback.
* <p>This method will open a connection to the database and retrieve the database meta-data.
* Since this method is called before the exception translation feature is configured for
* a datasource, this method can not rely on the SQLException translation functionality.
* <p>Any exceptions will be wrapped in a MetaDataAccessException. This is a checked exception
* and any calling code should catch and handle this exception. You can just log the
* error and hope for the best, but there is probably a more serious error that will
* reappear when you try to access the database again.
* <p>This method will open a connection to the database and retrieve its meta-data.
* Since this method is called before the exception translation feature is configured
* for a DataSource, this method can not rely on SQLException translation itself.
* <p>Any exceptions will be wrapped in a MetaDataAccessException. This is a checked
* exception and any calling code should catch and handle this exception. You can just
* log the error and hope for the best, but there is probably a more serious error that
* will reappear when you try to access the database again.
* @param dataSource the DataSource to extract meta-data for
* @param action callback that will do the actual work
* @return object containing the extracted information, as returned by
* the DatabaseMetaDataCallback's {@code processMetaData} method
* @throws MetaDataAccessException if meta-data access failed
* @see java.sql.DatabaseMetaData
*/
public static Object extractDatabaseMetaData(DataSource dataSource, DatabaseMetaDataCallback action)
throws MetaDataAccessException {
@@ -324,11 +325,24 @@ public abstract class JdbcUtils {
Connection con = null;
try {
con = DataSourceUtils.getConnection(dataSource);
if (con == null) {
// should only happen in test environments
throw new MetaDataAccessException("Connection returned by DataSource [" + dataSource + "] was null");
DatabaseMetaData metaData;
try {
metaData = con.getMetaData();
}
catch (SQLException ex) {
if (DataSourceUtils.isConnectionTransactional(con, dataSource)) {
// Probably a closed thread-bound Connection - retry against fresh Connection
DataSourceUtils.releaseConnection(con, dataSource);
con = null;
logger.debug("Failed to obtain DatabaseMetaData from transactional Connection - " +
"retrying against fresh Connection", ex);
con = dataSource.getConnection();
metaData = con.getMetaData();
}
else {
throw ex;
}
}
DatabaseMetaData metaData = con.getMetaData();
if (metaData == null) {
// should only happen in test environments
throw new MetaDataAccessException("DatabaseMetaData returned by Connection [" + con + "] was null");
@@ -458,9 +472,9 @@ public abstract class JdbcUtils {
* expressed in the JDBC 4.0 specification:
* <p><i>columnLabel - the label for the column specified with the SQL AS clause.
* If the SQL AS clause was not specified, then the label is the name of the column</i>.
* @return the column name to use
* @param resultSetMetaData the current meta-data to use
* @param columnIndex the index of the column for the look up
* @return the column name to use
* @throws SQLException in case of lookup failure
*/
public static String lookupColumnName(ResultSetMetaData resultSetMetaData, int columnIndex) throws SQLException {