org.springframework.jdbc.support

Class JdbcUtils

java.lang.Object

org.springframework.jdbc.support.JdbcUtils

public abstract class JdbcUtils
extends Object

Generic utility methods for working with JDBC. Mainly for internal use within the framework, but also useful for custom JDBC access code.

Author:

Thomas Risberg, Juergen Hoeller

Field Summary

Fields

Modifier and Type	Field and Description
static int	TYPE_UNKNOWN Constant that indicates an unknown (or unspecified) SQL type.

Constructor Summary

Constructors

Constructor and Description
JdbcUtils()

Method Summary

Modifier and Type	Method and Description
static void	closeConnection(Connection con) Close the given JDBC Connection and ignore any thrown exception.
static void	closeResultSet(ResultSet rs) Close the given JDBC ResultSet and ignore any thrown exception.
static void	closeStatement(Statement stmt) Close the given JDBC Statement and ignore any thrown exception.
static String	commonDatabaseName(String source) Extract a common name for the target database in use even if various drivers/platforms provide varying names at runtime.
static String	convertUnderscoreNameToPropertyName(String name) Convert a column name with underscores to the corresponding property name using "camel case".
static Object	extractDatabaseMetaData(DataSource dataSource, DatabaseMetaDataCallback action) Extract database meta-data via the given DatabaseMetaDataCallback.
static <T> T	extractDatabaseMetaData(DataSource dataSource, String metaDataMethodName) Call the specified method on DatabaseMetaData for the given DataSource, and extract the invocation result.
static Object	getResultSetValue(ResultSet rs, int index) Retrieve a JDBC column value from a ResultSet, using the most appropriate value type.
static Object	getResultSetValue(ResultSet rs, int index, Class<?> requiredType) Retrieve a JDBC column value from a ResultSet, using the specified value type.
static boolean	isNumeric(int sqlType) Check whether the given SQL type is numeric.
static String	lookupColumnName(ResultSetMetaData resultSetMetaData, int columnIndex) Determine the column name to use.
static String	resolveTypeName(int sqlType) Resolve the standard type name for the given SQL type, if possible.
static boolean	supportsBatchUpdates(Connection con) Return whether the given JDBC driver supports JDBC 2.0 batch updates.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TYPE_UNKNOWN

public static final int TYPE_UNKNOWN

Constant that indicates an unknown (or unspecified) SQL type.

See Also:

Types, Constant Field Values

Constructor Detail

JdbcUtils

public JdbcUtils()

Method Detail

closeConnection

public static void closeConnection(@Nullable
                                   Connection con)

Close the given JDBC Connection and ignore any thrown exception. This is useful for typical finally blocks in manual JDBC code.

Parameters:

con - the JDBC Connection to close (may be null)

closeStatement

public static void closeStatement(@Nullable
                                  Statement stmt)

Close the given JDBC Statement and ignore any thrown exception. This is useful for typical finally blocks in manual JDBC code.

Parameters:

stmt - the JDBC Statement to close (may be null)

closeResultSet

public static void closeResultSet(@Nullable
                                  ResultSet rs)

Close the given JDBC ResultSet and ignore any thrown exception. This is useful for typical finally blocks in manual JDBC code.

Parameters:

rs - the JDBC ResultSet to close (may be null)

getResultSetValue

@Nullable
public static Object getResultSetValue(ResultSet rs,
                                                 int index,
                                                 @Nullable
                                                 Class<?> requiredType)
                                          throws SQLException

Retrieve a JDBC column value from a ResultSet, using the specified value type.

Uses the specifically typed ResultSet accessor methods, falling back to getResultSetValue(java.sql.ResultSet, int) for unknown types.

Note that the returned value may not be assignable to the specified required type, in case of an unknown type. Calling code needs to deal with this case appropriately, e.g. throwing a corresponding exception.

Parameters:

rs - is the ResultSet holding the data

index - is the column index

requiredType - the required value type (may be null)

Returns:

the value object (possibly not of the specified required type, with further conversion steps necessary)

Throws:

SQLException - if thrown by the JDBC API

See Also:

getResultSetValue(ResultSet, int)

getResultSetValue

@Nullable
public static Object getResultSetValue(ResultSet rs,
                                                 int index)
                                          throws SQLException

Retrieve a JDBC column value from a ResultSet, using the most appropriate value type. The returned value should be a detached value object, not having any ties to the active ResultSet: in particular, it should not be a Blob or Clob object but rather a byte array or String representation, respectively.

Uses the getObject(index) method, but includes additional "hacks" to get around Oracle 10g returning a non-standard object for its TIMESTAMP datatype and a java.sql.Date for DATE columns leaving out the time portion: These columns will explicitly be extracted as standard java.sql.Timestamp object.

Parameters:

rs - is the ResultSet holding the data

index - is the column index

Returns:

the value object

Throws:

SQLException - if thrown by the JDBC API

See Also:

Blob, Clob, Timestamp

extractDatabaseMetaData

public static Object extractDatabaseMetaData(DataSource dataSource,
                                             DatabaseMetaDataCallback action)
                                      throws MetaDataAccessException

Extract database meta-data via the given DatabaseMetaDataCallback.

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.

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.

Parameters:

dataSource - the DataSource to extract meta-data for

action - callback that will do the actual work

Returns:

object containing the extracted information, as returned by the DatabaseMetaDataCallback's processMetaData method

Throws:

MetaDataAccessException - if meta-data access failed

extractDatabaseMetaData

public static <T> T extractDatabaseMetaData(DataSource dataSource,
                                            String metaDataMethodName)
                                     throws MetaDataAccessException

Call the specified method on DatabaseMetaData for the given DataSource, and extract the invocation result.

Parameters:

dataSource - the DataSource to extract meta-data for

metaDataMethodName - the name of the DatabaseMetaData method to call

Returns:

the object returned by the specified DatabaseMetaData method

Throws:

MetaDataAccessException - if we couldn't access the DatabaseMetaData or failed to invoke the specified method

See Also:

DatabaseMetaData

supportsBatchUpdates

public static boolean supportsBatchUpdates(Connection con)

Return whether the given JDBC driver supports JDBC 2.0 batch updates.

Typically invoked right before execution of a given set of statements: to decide whether the set of SQL statements should be executed through the JDBC 2.0 batch mechanism or simply in a traditional one-by-one fashion.

Logs a warning if the "supportsBatchUpdates" methods throws an exception and simply returns false in that case.

Parameters:

con - the Connection to check

Returns:

whether JDBC 2.0 batch updates are supported

See Also:

DatabaseMetaData.supportsBatchUpdates()

commonDatabaseName

@Nullable
public static String commonDatabaseName(@Nullable
                                                  String source)

Extract a common name for the target database in use even if various drivers/platforms provide varying names at runtime.

Parameters:

source - the name as provided in database meta-data

Returns:

the common name to be used (e.g. "DB2" or "Sybase")

isNumeric

public static boolean isNumeric(int sqlType)

Check whether the given SQL type is numeric.

Parameters:

sqlType - the SQL type to be checked

Returns:

whether the type is numeric

resolveTypeName

@Nullable
public static String resolveTypeName(int sqlType)

Resolve the standard type name for the given SQL type, if possible.

Parameters:

sqlType - the SQL type to resolve

Returns:

the corresponding constant name in Types (e.g. "VARCHAR"/"NUMERIC"), or null if not resolvable

Since:

5.2

lookupColumnName

public static String lookupColumnName(ResultSetMetaData resultSetMetaData,
                                      int columnIndex)
                               throws SQLException

Determine the column name to use. The column name is determined based on a lookup using ResultSetMetaData.

This method implementation takes into account recent clarifications expressed in the JDBC 4.0 specification:

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.

Parameters:

resultSetMetaData - the current meta-data to use

columnIndex - the index of the column for the look up

Returns:

the column name to use

Throws:

SQLException - in case of lookup failure

convertUnderscoreNameToPropertyName

public static String convertUnderscoreNameToPropertyName(@Nullable
                                                         String name)

Convert a column name with underscores to the corresponding property name using "camel case". A name like "customer_number" would match a "customerNumber" property name.

Parameters:

name - the column name to be converted

Returns:

the name using "camel case"