Encounter double number too large, turn string into scientific counting method

Problem:

　In Java, when the double number is too large, the string is turned out to be a representation of the scientific notation.

Summarize:

　　1. The project is stored with a mapping relationship between the type of Mysql,mysql and the Java type, which was previously of little concern. Now summarize:

　　

Type name	Display length	Database type	Java type	JDBC Type index (int)	Describe
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	With 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

2. for Bolb, generally used for image database storage, the principle is to make the picture into binary, and then do a storage method, in Java corresponding to the byte[] array.

3. For the Boolen type, in the MySQL database, the individual thinks that the use of the int type is better, the bit operation is not very convenient, especially in the project with Web page development, represents 0/1, corresponding to the Java type of integer is better.

4. The problem I encountered this time, I use the solution is the MySQL end with a decimal to store, and then the Java side with BigDecimal to receive,

Involves some of the uses of decimal:

• decimal Turn int

BigDecimal a=New BigDecimal (12.88); int

• int to decimal

New BigDecimal (int val);

　　　　

　　

Encounter double number too large, turn string into scientific counting method