使用MyBatis注解开发，可以省去类配置文件，简洁方便。但是比较复杂的SQL和动态SQL还是建议书写类配置文件。
注解还是不推荐使用的。只是了解了解！ 简单的CRUD可以使用注解。简单写写。
把之前的例子改成使用注解的。
UserMapper.java
package cn.itxm.mybatis.mapper;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Options;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.ResultMap;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import cn.itxm.mybatis.beans.UserBean;
public interface UserMapper {
// 简单的增删改查可以使用注解
// 注解+配置文件
/**
* 新增用戶
* @param user
* @return
* @throws Exception
*/
@Insert("insert into t_user value (null,user.username,user.password,user.account)")
@Options(useGeneratedKeys=true,keyProperty="user.id")
public int insertUser(@Param("user")UserBean user) throws Exception;
/**
* 修改用戶
* @param user
* @param id
* @return
* @throws Exception
*/
@Update(" update t_user set username=#{u.username},password=#{u.password},account=#{u.account} where id=#{id}")
public int updateUser (@Param("u")UserBean user,@Param("id")int id) throws Exception;
/**
* 刪除用戶
* @param id
* @return
* @throws Exception
*/
@Delete(" delete from t_user where id=#{id} ")
public int deleteUser(int id) throws Exception;
/**
* 根据id查询用户信息
* @param id
* @return
* @throws Exception
*/
@Select(" select * from t_user where id=#{id}")
@Results({
@Result(id=true,property="id",column="id",javaType=Integer.class),
@Result(property="username",column="username",javaType=String.class),
@Result(property="password",column="password",javaType=String.class),
@Result(property="account",column="account",javaType=Double.class)
})
public UserBean selectUserById(int id) throws Exception;
/**
* 查询所有的用户信息
* @return
* @throws Exception
*/
@Select(" select * from t_user")
@ResultMap("userMap")
public List<UserBean> selectAllUser() throws Exception;
/**
* 批量增加
* @param user
* @return
* @throws Exception
*/
public int batchInsertUser(@Param("users")List<UserBean> user) throws Exception;
/**
* 批量删除
* @param list
* @return
* @throws Exception
*/
public int batchDeleteUser(@Param("list")List<Integer> list) throws Exception;
/**
* 分页查询数据
* @param parma
* @return
* @throws Exception
*/
public List<UserBean> pagerUser(Map<String, Object> parmas) throws Exception;
/**
*
* 分页统计数据
* @param parma
* @return
* @throws Exception
*/
public int countUser(Map<String, Object> parmas) throws Exception;
}UserMapper.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.itxm.mybatis.mapper.UserMapper">
<!-- 自定义返回结果集 -->
<resultMap id="userMap" type="UserBean">
<id property="id" column="id" javaType="java.lang.Integer"></id>
<result property="username" column="username" javaType="java.lang.String"></result>
<result property="password" column="password" javaType="java.lang.String"></result>
<result property="account" column="account" javaType="java.lang.Double"></result>
</resultMap>
<!-- 批量操作和foreach标签 -->
<insert id="batchInsertUser" parameterType="java.util.List">
insert into t_user values
<foreach collection="users" item="users" separator=",">
(null,#{users.username},#{users.password},#{users.account})
</foreach>
</insert>
<delete id="batchDeleteUser">
delete from t_user where id in (
<foreach collection="list" item="list" separator=",">
#{id}
</foreach>
)
</delete>
<!--collection 为用于遍历的元素（必选），支持数组、List、Set -->
<!-- item 表示集合中每一个元素进行迭代时的别名. -->
<!--separator表示在每次进行迭代之间以什么符号作为分隔 符. -->
<!--#在生成SQL时，对于字符类型参数，会拼装引号
$在生成SQL时，不会拼装引号，可用于order by之类的参数拼装
-->
<select id="pagerUser" parameterType="java.util.Map" resultMap="userMap">
select * from t_user where 1=1
<if test="username!=null">
and username like '%${username}%'
</if>
limit ${index},${pageSize}
</select>
<select id="countUser" parameterType="java.util.Map" resultType="int">
select count(*) from t_user where 1=1
<if test="username != null">
and username like '%${username}%'
</if>
</select>
</mapper>简单的一个一对一的使用注解的。
package com.lovo.mybatis.mapper;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.One;
import org.apache.ibatis.annotations.Options;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.ResultType;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import com.lovo.mybatis.beans.HusbandBean;
import com.lovo.mybatis.beans.WifeBean;
public interface HusbandMapper {
/** * 保存丈夫
* @param husband
* @return */
@Insert("insert into t_husband values (null,#{h.name})")
@Options(useGeneratedKeys=true,keyProperty="h.id")
public int saveHusband(@Param("h")HusbandBean husband);
/** * 根据ID查询丈夫资料
* @param id
* @return */
@Select("select * from t_husband where id=#{id}")
@ResultType(HusbandBean.class)
public HusbandBean findHusbandById(int id);
/*** 根据ID查询丈夫与妻子资料
* @param id
* @return */
@Select("select * from t_husband where id=#{id}")
@Results({
@Result(id=true,property="id",column="id",javaType=Integer.class),
@Result(property="name",column="name",javaType=String.class),
@Result(property="wife",column="id",javaType=WifeBean.class,[email protected](select="com.lovo.mybatis.mapper.WifeMapper.findWifeByHusbandId"))
})
public HusbandBean findHusbandAndWife(int id);
}package cn.itxm.mybatis.mapper;
import org.apache.ibatis.annotations.ResultType;
import org.apache.ibatis.annotations.Select;
import cn.itxm.mybatis.beans.WifeBean;
public interface WifeMapper {
@Select("select * from t_wife where fk_husband_id = #{id}")
@ResultType(WifeBean.class)
public WifeBean selectWifeByHusbandId(int id)throws Exception;
}注意：使用resultType时，一定要保证，你属性名与字段名相同；如果不相同，就使用resultMap 。
原创文章，作者：奋斗，如若转载，请注明出处：https://blog.ytso.com/14100.html