1，将数据库的配置信息拿出来，单独放在db.properties文件里。
2，为实体类定义别名(在conf.xml文件中定义别名)，简化sql映射xml文件中的引用。
设置实体类别用之后，UserMapper.xml文件里何以简写不少,resultType的参数由“com.zhl.obj.User”简写为“User”
全部完整代码下载地址：https://git.oschina.net/zhuhongliang/SimpleMybatisDemo/tree/optimization/
<?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>
<!--引入properties文件!-->
<properties resource = "db.properties"/>
<!--设置别名!-->
<typeAliases>
<package name="com.zhl.obj"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<!-- 配置数据库连接信息 -->
<dataSource type="POOLED">
<property name="driver" value="${driver}" />
<property name="url" value="${url}" />
<property name="username" value="${name}" />
<property name="password" value="${password}" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/zhl/mapping/userMapper.xml"/>
<mapper class="com.zhl.mapping.UserMapperI" />
</mappers>
</configuration>
设置实体类别用之后，UserMapper.xml文件里何以简写不少,resultType的参数由“com.zhl.obj.User”改为“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.zhl.mapping.userMapper">
<!-- 查一个 -->
<select id="getUser" parameterType="int" resultType="User">
select * from users where id=#{id}
</select>
<!-- 增 -->
<insert id="addUser" parameterType="User">
insert into users(name, age) values(#{name}, #{age})
</insert>
<!-- 删 -->
<delete id="deleteUser" parameterType="String">
delete from users where name=#{name}
</delete>
<!-- 改 -->
<update id="updateUser" parameterType="User">
update users set name=#{name}, age=#{age} where id=#{id}
</update>
<!-- 查全部 -->
<select id="getAll" resultType="User">
select * from users
</select>
</mapper>
全部完整代码下载地址：https://git.oschina.net/zhuhongliang/SimpleMybatisDemo/tree/optimization/