Mybatis Typealiases (alias) in global configuration file

In a specific mapper.xml file, defining a lot of statement,statement requires parametertype specifying the type of input parameter, the type of mapping that needs to be resulttype to specify the output result.

If you enter a type full path when specifying a type, it is inconvenient to develop, you can define some aliases for the type specified by ParameterType or Resulttype, and the alias definition in mapper.xml to facilitate development.

one. MyBatis Default support aliases

Alias	Types of mappings
_byte	Byte
_long	Long
_short	Short
_int	Int
_integer	Int
_double	Double
_float	Float
_boolean	Boolean
String	String
Byte	Byte
Long	Long
Short	Short
Int	Integer
Integer	Integer
Double	Double
Float	Float
Boolean	Boolean
Date	Date
Decimal	BigDecimal
BigDecimal	BigDecimal

As shown in the following illustration: Int is an alias;

two. Custom aliases

Individual definition aliases

Use the typealiases tag to define the alias; alias the Cn.itcast.mybatis.po.User to User;

[HTML] view plain copy <!--alias definition-<typeAliases> <!--define type for a single alias: path alias for a type : Alias--<typealias type= "Cn.itcast.mybatis.po.User" alias= "User"/> </typeAliases>

Bulk definition aliases

MyBatis automatically scans the PO class in the package, automatically defines the alias, which is the class name (uppercase or lowercase, usually lowercase)

For example: Cn.itcast.mybatis.po.User alias for user or user;

[HTML] view plain copy <!--alias definition-<typeAliases> <!--batch alias definition, specify package name, MyBatis automatically scans the PO class in the package, automatically Define aliases, which are class names (either uppercase or lowercase, usually lowercase)-<package name= "Cn.itcast.mybatis.po"/> </typeAliases>

In the Mapper.xml file

Before the alias is defined

[HTML] view plain copy <select id= "Finduserbyid" parametertype= "int" resulttype= "Cn.itcast.mybatis.po. User "> select * from USER where id = #{id} </select>

Alias user is used in direct resulttype after defining aliases;

[HTML]   View plain  copy <select id= "Finduserbyid"  parametertype= "int"        resulttype= "User" >