mysql与java类型转换_MySql与Java 数据类型转换

Type Conversions Supported by MySQL Connector/J

MySQL Connector/J is flexible in the way it handles conversions between MySQL data types and Java data types.

In general, any MySQL data type can be converted to a java.lang.String, and any numerical type can be converted to any of the Java numerical types, although round-off, overflow, or loss of precision may occur.

The conversions that are always guaranteed to work are listed in the following table:

Table A.1. Conversion Table

These MySQL Data Types

Can always be converted to these Java types

CHAR, VARCHAR, BLOB, TEXT, ENUM, and SET

java.lang.String, java.io.InputStream, java.io.Reader, java.sql.Blob, java.sql.Clob

FLOAT, REAL, DOUBLE PRECISION, NUMERIC, DECIMAL, TINYINT, SMALLINT, MEDIUMINT, INTEGER, BIGINT

java.lang.String, java.lang.Short, java.lang.Integer, java.lang.Long, java.lang.Double, java.math.BigDecimal

Note

round-off, overflow or loss of precision may occur if you choose a Java numeric data type that has less precision or capacity than the MySQL data type you are converting to/from.

DATE, TIME, DATETIME, TIMESTAMP

java.lang.String, java.sql.Date, java.sql.Timestamp

Columns with an unsigned numeric type in MySQL are treated as the next 'larger' Java type that the signed variant of the MySQL type maps to:

Table A.2. Unsigned Types Mapping

MySQL Type

Corresponding Java Type

TINYINT UNSIGNED

java.lang.Integer

SMALLINT UNSIGNED

java.lang.Integer

MEDIUMINT UNSIGNED

java.lang.Long

INT UNSIGNED

java.lang.Long

BIGINT UNSIGNED

java.math.BigInteger

Note

Before MySQL Connector/J 3.1.3, BIGINT UNSIGNED was mapped to java.math.BigDecimal.