apache/shardingsphere · error · UnsupportedDataTypeConversionException

Unsupported conversion data type '%s' for value '%s'.

Error message

Unsupported conversion data type '%s' for value '%s'.

What it means

UnsupportedDataTypeConversionException from MySQLResultSetValueConverter.convertByteValue: the value's UTF-8 bytes must be exactly 1 byte long to convert to a byte; any other length (empty string, multi-byte character, multi-char text) throws. This enforces MySQL's single-character TINYINT/BYTE coercion semantics.

Source

Thrown at jdbc/src/main/java/org/apache/shardingsphere/driver/jdbc/core/resultset/MySQLResultSetValueConverter.java:86

                case "java.math.BigDecimal":
                    return stringValue.isEmpty() ? BigDecimal.ZERO : convertNumericValue(stringValue, convertType);
                default:
                    return ResultSetUtils.convertValue(value, convertType);
            }
        } catch (final NumberFormatException | ArithmeticException ignored) {
            throw new UnsupportedDataTypeConversionException(convertType, value);
        }
    }
    
    @Override
    public String getType() {
        return "MySQL";
    }
    
    private byte convertByteValue(final String value, final Class<?> convertType) {
        byte[] bytes = value.getBytes(StandardCharsets.UTF_8);
        if (1 != bytes.length) {
            throw new UnsupportedDataTypeConversionException(convertType, value);
        }
        return bytes[0];
    }
    
    private Boolean convertBooleanValue(final String value, final Class<?> convertType) {
        if ("Y".equalsIgnoreCase(value) || "yes".equalsIgnoreCase(value) || "T".equalsIgnoreCase(value) || "true".equalsIgnoreCase(value)) {
            return true;
        }
        if ("N".equalsIgnoreCase(value) || "no".equalsIgnoreCase(value) || "F".equalsIgnoreCase(value) || "false".equalsIgnoreCase(value)) {
            return false;
        }
        if (value.contains("e") || value.contains("E") || FLOATING_POINT_PATTERN.matcher(value).matches()) {
            return convertDoubleToBoolean(Double.parseDouble(value));
        }
        if (INTEGER_PATTERN.matcher(value).matches()) {
            return isSignedLong(value) ? longToBoolean(Long.parseLong(value)) : convertBigIntegerToBoolean(new BigInteger(value));
        }
        throw new UnsupportedDataTypeConversionException(convertType, value);

View on GitHub (pinned to e952770a21)

Solutions

1. Use getInt/getLong/getBigDecimal for numeric columns instead of getByte.
2. If the column is a single-character flag, ensure stored values are exactly one character and non-empty (trim on write).
3. Read with getString and convert explicitly with your own validation.

Example fix

// before
byte b = rs.getByte("FLAG"); // FLAG = "42"
// after
int b = rs.getInt("FLAG");

String s = rs.getString(col);
if (s == null || s.getBytes(UTF_8).length != 1) doNotCallGetByte();

boolean isSingleAsciiByte(String s) { return s != null && s.length() == 1 && s.charAt(0) < 128; }

catch (UnsupportedDataTypeConversionException ex) { use getInt/getString instead; }

When it happens

Trigger: Calling getByte on a column whose string value is not exactly one character — e.g. '42', 'Y ', '', or a multi-byte Unicode character — routed through the MySQL converter.

Common situations: Assuming getByte parses numbers (it does not here — it takes a single character's byte value); trailing whitespace or empty strings in char columns; multi-byte UTF-8 content; reading flags stored as words ('yes') instead of single chars.

Related errors

• 0
• Can not support date format if year, month, day is absent.
• 0
• getObject with type
• Can not support type `%s`.

AI-assisted analysis of apache/shardingsphere@e952770a21 (2026-08-14). Data as JSON: /api/errors/a58377c01b221df7. Report an issue: GitHub.