org.springframework.core.convert.ConverterNotFoundException#org.springframework.dao.TypeMismatchDataAccessException源码实例Demo

@Override
@Nullable
public Object readValueForProperty(@Nullable Value value, TypeInformation<?> type) {

	boolean valueIsLiteralNullOrNullValue = value == null || value == Values.NULL;

	try {
		Class<?> rawType = type.getType();

		if (!valueIsLiteralNullOrNullValue && isCollection(type)) {
			Collection<Object> target = createCollection(rawType, type.getComponentType().getType(), value.size());
			value.values().forEach(
				element -> target.add(conversionService.convert(element, type.getComponentType().getType())));
			return target;
		}

		return conversionService.convert(valueIsLiteralNullOrNullValue ? null : value, rawType);
	} catch (Exception e) {
		String msg = String.format("Could not convert %s into %s", value, type.toString());
		throw new TypeMismatchDataAccessException(msg, e);
	}
}
 

/**
 * Return a unique result object from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to the
 * specified required type.
 * @param results the result Collection (can be {@code null}
 * but is not expected to contain {@code null} elements)
 * @return the unique result object
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object does
 * not match the specified required type
 */
@SuppressWarnings("unchecked")
public static <T> T objectResult(@Nullable Collection<?> results, @Nullable Class<T> requiredType)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	Object result = requiredUniqueResult(results);
	if (requiredType != null && !requiredType.isInstance(result)) {
		if (String.class == requiredType) {
			result = result.toString();
		}
		else if (Number.class.isAssignableFrom(requiredType) && Number.class.isInstance(result)) {
			try {
				result = NumberUtils.convertNumberToTargetClass(((Number) result), (Class<? extends Number>) requiredType);
			}
			catch (IllegalArgumentException ex) {
				throw new TypeMismatchDataAccessException(ex.getMessage());
			}
		}
		else {
			throw new TypeMismatchDataAccessException(
					"Result object is of type [" + result.getClass().getName() +
					"] and could not be converted to required type [" + requiredType.getName() + "]");
		}
	}
	return (T) result;
}
 

/**
 * Return a unique result object from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to the
 * specified required type.
 * @param results the result Collection (can be {@code null}
 * but is not expected to contain {@code null} elements)
 * @return the unique result object
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object does
 * not match the specified required type
 */
@SuppressWarnings("unchecked")
public static <T> T objectResult(@Nullable Collection<?> results, @Nullable Class<T> requiredType)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	Object result = requiredUniqueResult(results);
	if (requiredType != null && !requiredType.isInstance(result)) {
		if (String.class == requiredType) {
			result = result.toString();
		}
		else if (Number.class.isAssignableFrom(requiredType) && Number.class.isInstance(result)) {
			try {
				result = NumberUtils.convertNumberToTargetClass(((Number) result), (Class<? extends Number>) requiredType);
			}
			catch (IllegalArgumentException ex) {
				throw new TypeMismatchDataAccessException(ex.getMessage());
			}
		}
		else {
			throw new TypeMismatchDataAccessException(
					"Result object is of type [" + result.getClass().getName() +
					"] and could not be converted to required type [" + requiredType.getName() + "]");
		}
	}
	return (T) result;
}
 

/**
 * Extract a value for the single column in the current row.
 * <p>Validates that there is only one column selected,
 * then delegates to {@code getColumnValue()} and also
 * {@code convertValueToRequiredType}, if necessary.
 * @see java.sql.ResultSetMetaData#getColumnCount()
 * @see #getColumnValue(java.sql.ResultSet, int, Class)
 * @see #convertValueToRequiredType(Object, Class)
 */
@Override
@SuppressWarnings("unchecked")
public T mapRow(ResultSet rs, int rowNum) throws SQLException {
	// Validate column count.
	ResultSetMetaData rsmd = rs.getMetaData();
	int nrOfColumns = rsmd.getColumnCount();
	if (nrOfColumns != 1) {
		throw new IncorrectResultSetColumnCountException(1, nrOfColumns);
	}

	// Extract column value from JDBC ResultSet.
	Object result = getColumnValue(rs, 1, this.requiredType);
	if (result != null && this.requiredType != null && !this.requiredType.isInstance(result)) {
		// Extracted value does not match already: try to convert it.
		try {
			return (T) convertValueToRequiredType(result, this.requiredType);
		}
		catch (IllegalArgumentException ex) {
			throw new TypeMismatchDataAccessException(
					"Type mismatch affecting row number " + rowNum + " and column type '" +
					rsmd.getColumnTypeName(1) + "': " + ex.getMessage());
		}
	}
	return (T) result;
}
 

/**
 * Return a unique result object from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to the
 * specified required type.
 * @param results the result Collection (can be {@code null})
 * @return the unique result object
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object does
 * not match the specified required type
 */
@SuppressWarnings("unchecked")
public static <T> T objectResult(Collection<?> results, Class<T> requiredType)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	Object result = requiredUniqueResult(results);
	if (requiredType != null && !requiredType.isInstance(result)) {
		if (String.class == requiredType) {
			result = result.toString();
		}
		else if (Number.class.isAssignableFrom(requiredType) && Number.class.isInstance(result)) {
			try {
				result = NumberUtils.convertNumberToTargetClass(((Number) result), (Class<? extends Number>) requiredType);
			}
			catch (IllegalArgumentException ex) {
				throw new TypeMismatchDataAccessException(ex.getMessage());
			}
		}
		else {
			throw new TypeMismatchDataAccessException(
					"Result object is of type [" + result.getClass().getName() +
					"] and could not be converted to required type [" + requiredType.getName() + "]");
		}
	}
	return (T) result;
}
 

/**
 * Return a unique result object from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertable to the
 * specified required type.
 * @param results the result Collection (can be {@code null})
 * @return the unique result object
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object does
 * not match the specified required type
 */
@SuppressWarnings("unchecked")
public static <T> T objectResult(Collection<?> results, Class<T> requiredType)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	Object result = requiredUniqueResult(results);
	if (requiredType != null && !requiredType.isInstance(result)) {
		if (String.class == requiredType) {
			result = result.toString();
		}
		else if (Number.class.isAssignableFrom(requiredType) && Number.class.isInstance(result)) {
			try {
				result = NumberUtils.convertNumberToTargetClass(((Number) result), (Class<? extends Number>) requiredType);
			}
			catch (IllegalArgumentException ex) {
				throw new TypeMismatchDataAccessException(ex.getMessage());
			}
		}
		else {
			throw new TypeMismatchDataAccessException(
					"Result object is of type [" + result.getClass().getName() +
					"] and could not be converted to required type [" + requiredType.getName() + "]");
		}
	}
	return (T) result;
}
 

/**
 * Extract a value for the single column in the current row.
 * <p>Validates that there is only one column selected,
 * then delegates to {@code getColumnValue()} and also
 * {@code convertValueToRequiredType}, if necessary.
 * @see java.sql.ResultSetMetaData#getColumnCount()
 * @see #getColumnValue(java.sql.ResultSet, int, Class)
 * @see #convertValueToRequiredType(Object, Class)
 */
@Override
@SuppressWarnings("unchecked")
public T mapRow(ResultSet rs, int rowNum) throws SQLException {
	// Validate column count.
	ResultSetMetaData rsmd = rs.getMetaData();
	int nrOfColumns = rsmd.getColumnCount();
	if (nrOfColumns != 1) {
		throw new IncorrectResultSetColumnCountException(1, nrOfColumns);
	}

	// Extract column value from JDBC ResultSet.
	Object result = getColumnValue(rs, 1, this.requiredType);
	if (result != null && this.requiredType != null && !this.requiredType.isInstance(result)) {
		// Extracted value does not match already: try to convert it.
		try {
			return (T) convertValueToRequiredType(result, this.requiredType);
		}
		catch (IllegalArgumentException ex) {
			throw new TypeMismatchDataAccessException(
					"Type mismatch affecting row number " + rowNum + " and column type '" +
					rsmd.getColumnTypeName(1) + "': " + ex.getMessage());
		}
	}
	return (T) result;
}
 

/**
 * Extract a value for the single column in the current row.
 * <p>Validates that there is only one column selected,
 * then delegates to {@code getColumnValue()} and also
 * {@code convertValueToRequiredType}, if necessary.
 * @see java.sql.ResultSetMetaData#getColumnCount()
 * @see #getColumnValue(java.sql.ResultSet, int, Class)
 * @see #convertValueToRequiredType(Object, Class)
 */
@Override
@SuppressWarnings("unchecked")
public T mapRow(ResultSet rs, int rowNum) throws SQLException {
	// Validate column count.
	ResultSetMetaData rsmd = rs.getMetaData();
	int nrOfColumns = rsmd.getColumnCount();
	if (nrOfColumns != 1) {
		throw new IncorrectResultSetColumnCountException(1, nrOfColumns);
	}

	// Extract column value from JDBC ResultSet.
	Object result = getColumnValue(rs, 1, this.requiredType);
	if (result != null && this.requiredType != null && !this.requiredType.isInstance(result)) {
		// Extracted value does not match already: try to convert it.
		try {
			return (T) convertValueToRequiredType(result, this.requiredType);
		}
		catch (IllegalArgumentException ex) {
			throw new TypeMismatchDataAccessException(
					"Type mismatch affecting row number " + rowNum + " and column type '" +
					rsmd.getColumnTypeName(1) + "': " + ex.getMessage());
		}
	}
	return (T) result;
}
 

@Test
void shouldCatchConversionErrors() {
	Value value = Values.value("Das funktioniert nicht.");

	assertThatExceptionOfType(TypeMismatchDataAccessException.class)
		.isThrownBy(() -> defaultNeo4jConverter.readValueForProperty(value, ClassTypeInformation.from(Date.class)))
		.withMessageStartingWith("Could not convert \"Das funktioniert nicht.\" into java.util.Date;")
		.withCauseInstanceOf(ConversionFailedException.class)
		.withRootCauseInstanceOf(DateTimeParseException.class);
}
 

@Test
void shouldCatchUncoercibleErrors() {
	Value value = Values.value("Das funktioniert nicht.");

	assertThatExceptionOfType(TypeMismatchDataAccessException.class)
		.isThrownBy(() -> defaultNeo4jConverter.readValueForProperty(value, ClassTypeInformation.from(LocalDate.class)))
		.withMessageStartingWith("Could not convert \"Das funktioniert nicht.\" into java.time.LocalDate;")
		.withCauseInstanceOf(ConversionFailedException.class)
		.withRootCauseInstanceOf(Uncoercible.class);
}
 

@Test
void shouldCatchUncoerfcibleErrors() {
	Value value = Values.value("Das funktioniert nicht.");

	assertThatExceptionOfType(TypeMismatchDataAccessException.class)
		.isThrownBy(
			() -> defaultNeo4jConverter.readValueForProperty(value, ClassTypeInformation.from(ReactiveNeo4jClient.class)))
		.withMessageStartingWith(
			"Could not convert \"Das funktioniert nicht.\" into org.neo4j.springframework.data.core.ReactiveNeo4jClient;")
		.withRootCauseInstanceOf(ConverterNotFoundException.class);
}
 

/**
 * Analogous to the SqlQuery.execute([]) method. This is a
 * generic method to execute a query, taken a number of arguments.
 * @param parameters array of parameters. These will be objects or
 * object wrapper types for primitives.
 * @return the value of the function
 */
public int run(Object... parameters) {
	Object obj = super.findObject(parameters);
	if (!(obj instanceof Number)) {
		throw new TypeMismatchDataAccessException("Couldn't convert result object [" + obj + "] to int");
	}
	return ((Number) obj).intValue();
}
 

/**
 * Extract a value for the single column in the current row.
 * <p>Validates that there is only one column selected,
 * then delegates to {@code getColumnValue()} and also
 * {@code convertValueToRequiredType}, if necessary.
 * @see java.sql.ResultSetMetaData#getColumnCount()
 * @see #getColumnValue(java.sql.ResultSet, int, Class)
 * @see #convertValueToRequiredType(Object, Class)
 */
@Override
@SuppressWarnings("unchecked")
@Nullable
public T mapRow(ResultSet rs, int rowNum) throws SQLException {
	// Validate column count.
	ResultSetMetaData rsmd = rs.getMetaData();
	int nrOfColumns = rsmd.getColumnCount();
	if (nrOfColumns != 1) {
		throw new IncorrectResultSetColumnCountException(1, nrOfColumns);
	}

	// Extract column value from JDBC ResultSet.
	Object result = getColumnValue(rs, 1, this.requiredType);
	if (result != null && this.requiredType != null && !this.requiredType.isInstance(result)) {
		// Extracted value does not match already: try to convert it.
		try {
			return (T) convertValueToRequiredType(result, this.requiredType);
		}
		catch (IllegalArgumentException ex) {
			throw new TypeMismatchDataAccessException(
					"Type mismatch affecting row number " + rowNum + " and column type '" +
					rsmd.getColumnTypeName(1) + "': " + ex.getMessage());
		}
	}
	return (T) result;
}
 

@Test(expected = TypeMismatchDataAccessException.class)  // SPR-16483
public void doesNotUseConversionService() throws SQLException {
	SingleColumnRowMapper<LocalDateTime> rowMapper =
			SingleColumnRowMapper.newInstance(LocalDateTime.class, null);

	ResultSet resultSet = mock(ResultSet.class);
	ResultSetMetaData metaData = mock(ResultSetMetaData.class);
	given(metaData.getColumnCount()).willReturn(1);
	given(resultSet.getMetaData()).willReturn(metaData);
	given(resultSet.getObject(1, LocalDateTime.class))
			.willThrow(new SQLFeatureNotSupportedException());
	given(resultSet.getTimestamp(1)).willReturn(new Timestamp(0));

	rowMapper.mapRow(resultSet, 1);
}
 

/**
 * Analogous to the SqlQuery.execute([]) method. This is a
 * generic method to execute a query, taken a number of arguments.
 * @param parameters array of parameters. These will be objects or
 * object wrapper types for primitives.
 * @return the value of the function
 */
public int run(Object... parameters) {
	Object obj = super.findObject(parameters);
	if (!(obj instanceof Number)) {
		throw new TypeMismatchDataAccessException("Couldn't convert result object [" + obj + "] to int");
	}
	return ((Number) obj).intValue();
}
 

/**
 * Extract a value for the single column in the current row.
 * <p>Validates that there is only one column selected,
 * then delegates to {@code getColumnValue()} and also
 * {@code convertValueToRequiredType}, if necessary.
 * @see java.sql.ResultSetMetaData#getColumnCount()
 * @see #getColumnValue(java.sql.ResultSet, int, Class)
 * @see #convertValueToRequiredType(Object, Class)
 */
@Override
@SuppressWarnings("unchecked")
@Nullable
public T mapRow(ResultSet rs, int rowNum) throws SQLException {
	// Validate column count.
	ResultSetMetaData rsmd = rs.getMetaData();
	int nrOfColumns = rsmd.getColumnCount();
	if (nrOfColumns != 1) {
		throw new IncorrectResultSetColumnCountException(1, nrOfColumns);
	}

	// Extract column value from JDBC ResultSet.
	Object result = getColumnValue(rs, 1, this.requiredType);
	if (result != null && this.requiredType != null && !this.requiredType.isInstance(result)) {
		// Extracted value does not match already: try to convert it.
		try {
			return (T) convertValueToRequiredType(result, this.requiredType);
		}
		catch (IllegalArgumentException ex) {
			throw new TypeMismatchDataAccessException(
					"Type mismatch affecting row number " + rowNum + " and column type '" +
					rsmd.getColumnTypeName(1) + "': " + ex.getMessage());
		}
	}
	return (T) result;
}
 

@Test(expected = TypeMismatchDataAccessException.class)  // SPR-16483
public void doesNotUseConversionService() throws SQLException {
	SingleColumnRowMapper<LocalDateTime> rowMapper =
			SingleColumnRowMapper.newInstance(LocalDateTime.class, null);

	ResultSet resultSet = mock(ResultSet.class);
	ResultSetMetaData metaData = mock(ResultSetMetaData.class);
	given(metaData.getColumnCount()).willReturn(1);
	given(resultSet.getMetaData()).willReturn(metaData);
	given(resultSet.getObject(1, LocalDateTime.class))
			.willThrow(new SQLFeatureNotSupportedException());
	given(resultSet.getTimestamp(1)).willReturn(new Timestamp(0));

	rowMapper.mapRow(resultSet, 1);
}
 

/**
 * Analogous to the SqlQuery.execute([]) method. This is a
 * generic method to execute a query, taken a number of arguments.
 * @param parameters array of parameters. These will be objects or
 * object wrapper types for primitives.
 * @return the value of the function
 */
public int run(Object... parameters) {
	Object obj = super.findObject(parameters);
	if (!(obj instanceof Number)) {
		throw new TypeMismatchDataAccessException("Couldn't convert result object [" + obj + "] to int");
	}
	return ((Number) obj).intValue();
}
 

/**
 * Analogous to the SqlQuery.execute([]) method. This is a
 * generic method to execute a query, taken a number of arguments.
 * @param parameters array of parameters. These will be objects or
 * object wrapper types for primitives.
 * @return the value of the function
 */
public int run(Object... parameters) {
	Object obj = super.findObject(parameters);
	if (!(obj instanceof Number)) {
		throw new TypeMismatchDataAccessException("Couldn't convert result object [" + obj + "] to int");
	}
	return ((Number) obj).intValue();
}
 

/**
 * Analogous to the SqlQuery.execute([]) method. This is a
 * generic method to execute a query, taken a number of arguments.
 * @param parameters array of parameters. These will be objects or
 * object wrapper types for primitives.
 * @return the value of the function
 */
public int run(Object... parameters) {
	Object obj = super.findObject(parameters);
	if (!(obj instanceof Number)) {
		throw new TypeMismatchDataAccessException("Couldn't convert result object [" + obj + "] to int");
	}
	return ((Number) obj).intValue();
}
 

/**
 * Return a unique int result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to an int.
 * @param results the result Collection (can be {@code null}
 * but is not expected to contain {@code null} elements)
 * @return the unique int result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertible to an int
 */
public static int intResult(@Nullable Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).intValue();
}
 

/**
 * Return a unique long result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to a long.
 * @param results the result Collection (can be {@code null}
 * but is not expected to contain {@code null} elements)
 * @return the unique long result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertible to a long
 */
public static long longResult(@Nullable Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).longValue();
}
 

/**
 * Return a unique int result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to an int.
 * @param results the result Collection (can be {@code null}
 * but is not expected to contain {@code null} elements)
 * @return the unique int result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertible to an int
 */
public static int intResult(@Nullable Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).intValue();
}
 

/**
 * Return a unique long result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to a long.
 * @param results the result Collection (can be {@code null}
 * but is not expected to contain {@code null} elements)
 * @return the unique long result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertible to a long
 */
public static long longResult(@Nullable Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).longValue();
}
 

/**
 * Return a unique int result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to an int.
 * @param results the result Collection (can be {@code null})
 * @return the unique int result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertible to an int
 */
public static int intResult(Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).intValue();
}
 

/**
 * Return a unique long result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertible to a long.
 * @param results the result Collection (can be {@code null})
 * @return the unique long result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertible to a long
 */
public static long longResult(Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).longValue();
}
 

/**
 * Return a unique int result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertable to an int.
 * @param results the result Collection (can be {@code null})
 * @return the unique int result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertable to an int
 */
public static int intResult(Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).intValue();
}
 

/**
 * Return a unique long result from the given Collection.
 * Throws an exception if 0 or more than 1 result objects found,
 * of if the unique result object is not convertable to a long.
 * @param results the result Collection (can be {@code null})
 * @return the unique long result
 * @throws IncorrectResultSizeDataAccessException if more than one
 * result object has been found in the given Collection
 * @throws EmptyResultDataAccessException if no result object
 * at all has been found in the given Collection
 * @throws TypeMismatchDataAccessException if the unique object
 * in the collection is not convertable to a long
 */
public static long longResult(Collection<?> results)
		throws IncorrectResultSizeDataAccessException, TypeMismatchDataAccessException {

	return objectResult(results, Number.class).longValue();
}