The use of Mybatis_ aliases

 

The definition of alias should be defined in sqlMapConfig.xml

Custom Aliases:

Since the type name behind the parameterType is very long, sometimes it is necessary to define an alias. Use the typeAliases tag to put

Example: xxx.x.Person is defined as person (just write person directly in the future)

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <!-- 
        type: the data type to be defined as an alias
         -->
        <typeAlias type="xxx.x.Person" alias = "person"/>
    </typeAliases>
    <!-- 
        If the database environment configuration is integrated with spring, it does not need to be configured, it is completely handed over to spring, and the following parts are eliminated.
     --> 
    < environments default = "development" >   <!-- What is the default name here, just call which environment below, that is, you can call a database (MYSQL or Oracle) --> 
        < environment id = "development" > 
            < transactionManager type ="JDBC"  /> 
            < dataSource type ="POOLED" > 
                < property name ="driver" value ="com.mysql.jdbc.Driver"  /> 
                < property name ="url" value ="jdbc: mysql://localhost:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
    
    <!-- 
        Manage mapping files for each table
        resource: import the mapping file, pay attention to the slashes between the packages
     -->
    <mappers>
        <mapper resource="xxx/x/mapper/PersonTestMapper.xml" />
    </mappers>
</configuration>

 

Non-custom aliases:

A non-custom alias means that all classes in the JDK use non-custom aliases, and the content of the alias is that all letters of the type are case-insensitive.

for example:

parameterType="java.util.Map"

can be written directly as

parameterType="map"

 

If it is a wrapper class, you can also use the name of its basic data type.

for example:

parameterType="java.lang.Integer"

can be written as

parameterType="int"

 

 

Replace some sql fragments: extract some common sql fragments

<sql id = "column"> is some public information.

    <sql id = "column">
        person_id,name,gender,person_addr,birthday
    </sql>
    <select id="selectPersonAll" resultMap="BaseResultMap" >
        select <include refid="column">  from person
    </select>