mybatis3 type alias

Problem Description

    <!-- 插入操作 需要user参数 -->
    <insert id="insertUser" parameterType="cn.bitqian.entity.User">
        insert into users1 values (#{userId}, #{userName}, #{userPassword})
    </insert>

    <!-- 修改操作 -->
    <update id="updateUser" parameterType="cn.bitqian.entity.User">
        update users1 set username = #{userName}, userpassword = #{userPassword}
        where userid = #{userId}
    </update>

    <!-- 根据id删除某个user -->
    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from users1 where userid = #{userId}
    </delete>

Each of the above parameterTypes must write the full package name + the class name, which is very
cumbersome, and all need to be labeled for extraction.

solution

类型别名可为 Java 类型设置一个缩写名字。
 它仅用于 XML 配置，意在降低冗余的全限定类名书写。

• Type aliases (typeAliases)

类型别名可为 Java 类型设置一个缩写名字。 
它仅用于 XML 配置，意在降低冗余的全限定类名书写。

<typeAliases>
  <typeAlias alias="user" type="cn.bitqian.entity.User"/>
  <typeAlias alias="user" type="cn.bitqian.entity.Order"/>
</typeAliases>

The writing becomes concise:

<mapper>
    <insert id="insertUser" parameterType="user">
        insert into users1 values (#{userId}, #{userName}, #{userPassword})
    </insert>
</mapper>

• Some data types provided by Java are compared with the corresponding types of mybatis

Alias	Mapping type
_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
object	Object
map	Map
hashmap	HashMap
list	List
arraylist	ArrayList
collection	Collection
iterator	Iterator

Option two, scan the package directly

<typeAliases>
  <package name="cn.bitqian.entity"/>
</typeAliases>

<mapper>
	<!-- 实体类名称 -->
    <insert id="insertUser" parameterType="User">
        insert into users1 values (#{userId}, #{userName}, #{userPassword})
    </insert>
</mapper>