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/