3.mybatis别名配置

在实际项目开发中,我们经常性的设置返回对象.而设置的对象是使用全限定名,太长了　也比较麻烦

例如:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  
<mapper namespace="com.gzcgxt.erp.UserMapper">
    <select id="select" resultType="com.gzcgxt.erp.hello.User">   # 就是这个 com.gzcgxt.erp.hello.
        select * from user where id = #{id}
    </select>
</mapper>

 

解决办法　在mybatis全局配置文件中使用 别名方式

mybatis.xml

<typeAliases>
　　　<package name="com.gzcgxt.erp.hello"/>
</typeAliases>

<?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>
        <package name="com.gzcgxt.erp.hello"/>
    </typeAliases>
    
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!-- 这个是数据库操作的xml文件 -->
        <mapper resource="UserMapper.xml"/>
    </mappers>
</configuration>

 

UserMapper.xml 配置文件

resultType="User"

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  
<mapper namespace="com.gzcgxt.erp.UserMapper">
    <select id="select" resultType="User">
        select * from user where id = #{id}
    </select>
</mapper>

 

测试代码