java.lang.AbstractMethodError: Method oracle/jdbc/driver/OracleResultSetImpl.getNString(Ljava/lang/String;)Ljava/lang/String; is abstract,

mapper.xml映射数据库和实体类报错

报错信息：java.lang.AbstractMethodError: Method oracle/jdbc/driver/OracleResultSetImpl.getNString(Ljava/lang/String;)Ljava/lang/String; is abstract,

问题：在mapper.xml代码中  jdbcType  定义的跟数据库中的和实体类中的不一致，

 

解决方案1：暴力解决，直接去掉mapper.xml中定义的resultMap中的jdbcType ，不指定数据类型

解决方案2：逐个检查 实体类、数据库、resultMap中的数据类型，这三者要保持一致

 

附：MySQL数据类型、JDBC数据类型、Java数据类型的默认映射关系

MySQL数据类型	JDBC类型(getColumnTypeName)	默认返回的Java类型(getColumnClassName)
BIT(1) (new in MySQL-5.0)	BIT	java.lang.Boolean
BIT( > 1) (new in MySQL-5.0)	BIT	byte[]
TINYINT	TINYINT	java.lang.Boolean if the configuration property tinyInt1isBit is set to true (the default) and the storage size is 1, or java.lang.Integer if not.
BOOL, BOOLEAN	TINYINT	See TINYINT, above as these are aliases for TINYINT(1), currently.
SMALLINT[(M)] [UNSIGNED]	SMALLINT [UNSIGNED]	java.lang.Integer (regardless of whether it is UNSIGNED or not)
MEDIUMINT[(M)] [UNSIGNED]	MEDIUMINT [UNSIGNED]	java.lang.Integer (regardless of whether it is UNSIGNED or not)
INT,INTEGER[(M)] [UNSIGNED]	INTEGER [UNSIGNED]	java.lang.Integer, if UNSIGNED java.lang.Long
BIGINT[(M)] [UNSIGNED]	BIGINT [UNSIGNED]	java.lang.Long, if UNSIGNED java.math.BigInteger
FLOAT[(M,D)]	FLOAT	java.lang.Float
DOUBLE[(M,B)]	DOUBLE	java.lang.Double
DECIMAL[(M[,D])]	DECIMAL	java.math.BigDecimal
DATE	DATE	java.sql.Date
DATETIME	DATETIME	java.sql.Timestamp
TIMESTAMP[(M)]	TIMESTAMP	java.sql.Timestamp
TIME	TIME	java.sql.Time
YEAR[(2|4)]	YEAR	If yearIsDateType configuration property is set to false, then the returned object type is java.sql.Short. If set to true (the default), then the returned object is of type java.sql.Datewith the date set to January 1st, at midnight.
CHAR(M)	CHAR	java.lang.String (unless the character set for the column is BINARY, then byte[] is returned.
VARCHAR(M) [BINARY]	VARCHAR	java.lang.String (unless the character set for the column is BINARY, then byte[] is returned.
BINARY(M)	BINARY	byte[]
VARBINARY(M)	VARBINARY	byte[]
TINYBLOB	TINYBLOB	byte[]
TINYTEXT	VARCHAR	java.lang.String
BLOB	BLOB	byte[]
TEXT	VARCHAR	java.lang.String
MEDIUMBLOB	MEDIUMBLOB	byte[]
MEDIUMTEXT	VARCHAR	java.lang.String
LONGBLOB	LONGBLOB	byte[]
LONGTEXT	VARCHAR	java.lang.String
ENUM('value1','value2',...)	CHAR	java.lang.String
SET('value1','value2',...)	CHAR	java.lang.String

MySQL JDBC允许不同数据类型之间相互转换：转换表如下 

MySQL数据类型	可以被转换的Java类型
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
DATE, TIME, DATETIME, TIMESTAMP	java.lang.String, java.sql.Date, java.sql.Timestamp

 

参考MySQL :: MySQL Connector/J 8.0 Developer Guide :: 6.5 Java, JDBC, and MySQL Types