碰到个问题，不知道mysql中ENUM到底是对应java中的哪个类型。
因此在mysql-connector-java源码中查了一下代码，顺便和大家分享一下:
mysql-connector-java-6.0.6中的数据类型和java数据类型的转换代码位置.png
几个关注点:
mysql中的基本数据类型，例如INT，BOOLEAN....等都对应为java的包装类(Integer，Boolean)
mysql中的JSON类型，对应的是java中的String类型
mysql中的ENUM类型，对应的是java中的String类型
为什么mysql中的BLOB系列类型，没有java的对应类型，都是null呢？
DECIMAL("DECIMAL", Types.DECIMAL, BigDecimal.class, MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 65L, "[(M[,D])] [UNSIGNED] [ZEROFILL]"),
DECIMAL_UNSIGNED("DECIMAL UNSIGNED", Types.DECIMAL, BigDecimal.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL,
65L, "[(M[,D])] [UNSIGNED] [ZEROFILL]"),
TINYINT("TINYINT", Types.TINYINT, Integer.class, MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 3L, "[(M)] [UNSIGNED] [ZEROFILL]"),
TINYINT_UNSIGNED("TINYINT UNSIGNED", Types.TINYINT, Integer.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 3L,
"[(M)] [UNSIGNED] [ZEROFILL]"),
BOOLEAN("BOOLEAN", Types.BOOLEAN, Boolean.class, 0, MysqlType.IS_NOT_DECIMAL, 3L, ""),
SMALLINT("SMALLINT", Types.SMALLINT, Integer.class, MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 5L, "[(M)] [UNSIGNED] [ZEROFILL]"),
SMALLINT_UNSIGNED("SMALLINT UNSIGNED", Types.SMALLINT, Integer.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL,
5L, "[(M)] [UNSIGNED] [ZEROFILL]"),
INT("INT", Types.INTEGER, Integer.class, MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 10L, "[(M)] [UNSIGNED] [ZEROFILL]"),
INT_UNSIGNED("INT UNSIGNED", Types.INTEGER, Long.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 10L,
"[(M)] [UNSIGNED] [ZEROFILL]"),
FLOAT("FLOAT", Types.REAL, Float.class, MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 12L, "[(M,D)] [UNSIGNED] [ZEROFILL]"),
FLOAT_UNSIGNED("FLOAT UNSIGNED", Types.REAL, Float.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 12L,
"[(M,D)] [UNSIGNED] [ZEROFILL]"),
DOUBLE_UNSIGNED("DOUBLE UNSIGNED", Types.DOUBLE, Double.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 22L,
"[(M,D)] [UNSIGNED] [ZEROFILL]"),
NULL("NULL", Types.NULL, Object.class, 0, MysqlType.IS_NOT_DECIMAL, 0L, ""),
TIMESTAMP("TIMESTAMP", Types.TIMESTAMP, Timestamp.class, 0, MysqlType.IS_NOT_DECIMAL, 26L, "[(fsp)]"),
BIGINT("BIGINT", Types.BIGINT, Long.class, MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 19L, "[(M)] [UNSIGNED] [ZEROFILL]"),
BIGINT_UNSIGNED("BIGINT UNSIGNED", Types.BIGINT, BigInteger.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 20L,
"[(M)] [UNSIGNED] [ZEROFILL]"),
MEDIUMINT("MEDIUMINT", Types.INTEGER, Integer.class, MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL, 7L, "[(M)] [UNSIGNED] [ZEROFILL]"),
MEDIUMINT_UNSIGNED("MEDIUMINT UNSIGNED", Types.INTEGER, Integer.class, MysqlType.FIELD_FLAG_UNSIGNED | MysqlType.FIELD_FLAG_ZEROFILL, MysqlType.IS_DECIMAL,
8L, "[(M)] [UNSIGNED] [ZEROFILL]"),
DATE("DATE", Types.DATE, Date.class, 0, MysqlType.IS_NOT_DECIMAL, 10L, ""),
TIME("TIME", Types.TIME, Time.class, 0, MysqlType.IS_NOT_DECIMAL, 16L, "[(fsp)]"),
DATETIME("DATETIME", Types.TIMESTAMP, Timestamp.class, 0, MysqlType.IS_NOT_DECIMAL, 26L, "[(fsp)]"),
YEAR("YEAR", Types.DATE, Date.class, 0, MysqlType.IS_NOT_DECIMAL, 4L, "[(4)]"),
VARCHAR("VARCHAR", Types.VARCHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 65535L, "(M) [CHARACTER SET charset_name] [COLLATE collation_name]"),
VARBINARY("VARBINARY", Types.VARBINARY, null, 0, MysqlType.IS_NOT_DECIMAL, 65535L, "(M)"),
BIT("BIT", Types.BIT, Boolean.class, 0, MysqlType.IS_DECIMAL, 1L, "[(M)]"), // TODO maybe precision=8 ?
JSON("JSON", Types.LONGVARCHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 1073741824L, ""),
ENUM("ENUM", Types.CHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 65535L,
"('value1','value2',...) [CHARACTER SET charset_name] [COLLATE collation_name]"),
SET("SET", Types.CHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 64L, "('value1','value2',...) [CHARACTER SET charset_name] [COLLATE collation_name]"),
TINYBLOB("TINYBLOB", Types.VARBINARY, null, 0, MysqlType.IS_NOT_DECIMAL, 255L, ""),
TINYTEXT("TINYTEXT", Types.VARCHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 255L, " [CHARACTER SET charset_name] [COLLATE collation_name]"),
MEDIUMBLOB("MEDIUMBLOB", Types.LONGVARBINARY, null, 0, MysqlType.IS_NOT_DECIMAL, 16777215L, ""),
MEDIUMTEXT("MEDIUMTEXT", Types.LONGVARCHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 16777215L, " [CHARACTER SET charset_name] [COLLATE collation_name]"),
LONGBLOB("LONGBLOB", Types.LONGVARBINARY, null, 0, MysqlType.IS_NOT_DECIMAL, 4294967295L, ""),
LONGTEXT("LONGTEXT", Types.LONGVARCHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 4294967295L, " [CHARACTER SET charset_name] [COLLATE collation_name]"),
BLOB("BLOB", Types.LONGVARBINARY, null, 0, MysqlType.IS_NOT_DECIMAL, 65535L, "[(M)]"),
TEXT("TEXT", Types.LONGVARCHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 65535L, "[(M)] [CHARACTER SET charset_name] [COLLATE collation_name]"),
CHAR("CHAR", Types.CHAR, String.class, 0, MysqlType.IS_NOT_DECIMAL, 255L, "[(M)] [CHARACTER SET charset_name] [COLLATE collation_name]"),
BINARY("BINARY", Types.BINARY, null, 0, MysqlType.IS_NOT_DECIMAL, 255L, "(M)"),
GEOMETRY("GEOMETRY", Types.BINARY, null, 0, MysqlType.IS_NOT_DECIMAL, 65535L, ""),
UNKNOWN("UNKNOWN", Types.OTHER, null, 0, MysqlType.IS_NOT_DECIMAL, 65535L, "");