MyBatis具体

准备工作

预编译SQL

新增

更新

查询

//查询员工@Select("select * from emp where id = #{id}")public Emp getById(Integer id);//方案一:给字段起别名，让别名与实体类属性一致@Select("select id,username,password,name,gender,image,job,entrydate,"+" dept_id deptId,create_time createTime,update_time updateTime from emp where id = #{id}")public Emp getById(Integer id);//方案二:通过@Results @Result注解手动映射封装方案(繁琐，不用)@Results({@Result(column = "dept_id",property = "deptId"),@Result(column = "create_time",property = "createTime"),@Result(column = "update_time",property = "updateTime")})@Select("select * from emp where id = #{id}")public Emp getById(Integer id);//方案三:开启mybatis的驼峰命名自动映射开关 a column ---> aColumn 在application.properties增加语句//mybatis.configuration.map-underscore-to-camel-case=true

条件查询

xml映射文件

Mybatis动态SQL

if

if例子

foreach

sql include