mysql-数据类型与java数据类型转化工具类

mysql和java对照表

类型名称	显示长度	数据库类型	JAVA类型	JDBC类型索引(int)	描述
VARCHAR	L+N	VARCHAR	java.lang.String	12
CHAR	N	CHAR	java.lang.String	1
BLOB	L+N	BLOB	java.lang.byte[]	-4
TEXT	65535	VARCHAR	java.lang.String	-1
INTEGER	4	INTEGER UNSIGNED	java.lang.Long	4
TINYINT	3	TINYINT UNSIGNED	java.lang.Integer	-6
SMALLINT	5	SMALLINT UNSIGNED	java.lang.Integer	5
MEDIUMINT	8	MEDIUMINT UNSIGNED	java.lang.Integer	4
BIT	1	BIT	java.lang.Boolean	-7
BIGINT	20	BIGINT UNSIGNED	java.math.BigInteger	-5
FLOAT	4+8	FLOAT	java.lang.Float	7
DOUBLE	22	DOUBLE	java.lang.Double	8
DECIMAL	11	DECIMAL	java.math.BigDecimal	3
BOOLEAN	1	同TINYINT
ID	11	PK (INTEGER UNSIGNED)	java.lang.Long	4
DATE	10	DATE	java.sql.Date	91
TIME	8	TIME	java.sql.Time	92
DATETIME	19	DATETIME	java.sql.Timestamp	93
TIMESTAMP	19	TIMESTAMP	java.sql.Timestamp	93
YEAR	4	YEAR	java.sql.Date	91

对于bolb，一般用于对图片的数据库存储，原理是把图片打成二进制，然后进行的一种存储方式，在java中对应byte［］数组。

对于boolen类型，在mysql数据库中，个人认为用int类型代替较好，对bit操作不是很方便，尤其是在具有web页面开发的项目中，表示0/1，对应java类型的Integer较好。

 

    /**
     * 数据类型转化JAVA
     * @param sqlType：类型名称
     * @return
     */
    public static String toSqlToJava(String sqlType) {
        if( sqlType == null || sqlType.trim().length() == 0 ) return sqlType;
        sqlType = sqlType.toLowerCase();
        switch(sqlType){
            case "nvarchar":return "String";
            case "char":return "String";
            case "varchar":return "String";
            case "text":return "String";
            case "nchar":return "String";
            case "blob":return "byte[]";
            case "integer":return "Long";
            case "tinyint":return "Integer";
            case "smallint":return "Integer";
            case "mediumint":return "Integer";
            case "bit":return "Boolean";
            case "bigint":return "java.math.BigInteger";
            case "float":return "Fload";
            case "double":return "Double";
            case "decimal":return "java.math.BigDecimal";
            case "boolean":return "Boolean";
            case "id":return "Long";
            case "date":return "java.util.Date";
            case "datetime":return "java.util.Date";
            case "year":return "java.util.Date";
            case "time":return "java.sql.Time";
            case "timestamp":return "java.sql.Timestamp";
            case "numeric":return "java.math.BigDecimal";
            case "real":return "java.math.BigDecimal";
            case "money":return "Double";
            case "smallmoney":return "Double";
            case "image":return "byte[]";
            default:
                System.out.println("-----------------》转化失败：未发现的类型"+sqlType);
                break;
        }
        return sqlType;
    }