Type Support

Redis organizes data as keys and native structures. The table lists Java types for common command results. See Java/JDBC types.

Type Mappings

Redis data type	Java type	Description
String	String	GET results are usually read as String; choose Long, Boolean, java.sql.Date or Instant only with a defined text format.
String	Map / List / Bean	When storing JSON text, see JSON Field Mapping.
String	Enum	Store enum names; declare the concrete enum class and keep values aligned with constant names.
String	BigDecimal	Store decimal text and read it as BigDecimal without precision loss.
String	BigInteger	Store integer text and read it as BigInteger.
String (binary content)	byte[]	SET accepts byte arrays; bind the GET key as byte[] to retrieve raw bytes.
Hash	String	HGETALL returns each field and value as String.
List	String	Each LRANGE result row contains one String element.
Set	String	Each SMEMBERS result row contains one String element.
Sorted Set	Double	Score returned by score-aware commands; approximate and unsuitable for exact decimal amounts.

Basic Types

Use native SET/HSET commands to store empty strings; the builder API does not provide Redis entity insertion.

Numbers, booleans, characters, and empty strings can be read and written. Redis values cannot store SQL NULL. To represent absence, delete the key; see Missing Values.

Time Types

Non-null date and time values can be converted using type handlers. A Java null cannot be stored as a Redis value; delete the key instead. See Missing Values.

Enum Types

Non-null enum names, codes, and values can be converted using the corresponding handler. A null enum cannot be stored as a Redis value; see Missing Values.

JSON Serialization

Objects and collections can be stored as JSON text. SQL NULL round trips are not supported. The JSON text null is not a missing Redis value; see Missing Values to represent absence.

Binary Types

Non-null byte arrays can be read and written; null byte arrays cannot be stored. To clear the value, see Missing Values.

A UTF-8 encoded text key identifies the same Redis key. Bind a byte-array key when reading to retrieve raw bytes without text decoding.

import java.nio.charset.StandardCharsets;

String key = "demo:binary";
byte[] content = new byte[] { 0, (byte) 255, (byte) 128 };
jdbc.executeUpdate("SET ? ?", new Object[] { key, content });
byte[] loaded = jdbc.queryForObject("GET ?",
        new Object[] { key.getBytes(StandardCharsets.UTF_8) }, byte[].class);

GET with a String key continues to return text. SET uses binary writes when its key or value is byte[]; SET ... GET also returns the previous value as raw bytes.

Limits

• Use SET/GET for exact decimals, not floating-point increment commands.
• Redis List / Set are native structures, not JDBC ARRAY values.

Array Types

Redis List and Set are not read or written through JDBC ARRAY mapping. Use list/set commands or JSON Field Mapping to store a collection.

Missing values

Redis cannot store SQL NULL values, including null enums and byte arrays. Use key or Hash-field deletion to represent absence; see NULL Parameters.