mybatis注解使用

　　spring整合mybatis时，要使用mybatis的注解，需要spring-config.xml文件中添加下述配置：　　

 <!--下述配置指明了我们的Mapper，即Dao，在相应的包里也就可以使用注解了，同时不用写Dao的实现类了  -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.itszt.dao"></property>
        <property name="sqlSessionFactoryBeanName"  value="sqlSessionFactory"></property>
    </bean>

　　UserDao.xml文件配置如下：　

<?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">
<!--
  保证命名空间，和接口的全类名一致
-->
<mapper namespace="com.itszt.dao.UserDao">
    <resultMap id="userMap" type="user">
        <id property="uid" column="uid"></id>
        <result property="username111" column="username"></result>
    </resultMap>
</mapper>

　　此时，在与UserDao.xml文件同一包下的UserDao接口可以直接写sql操作语句：

package com.itszt.dao;
import com.itszt.domain.User;
import com.itszt.domain.User2;
import org.apache.ibatis.annotations.*;
import org.springframework.stereotype.Repository;
import java.util.List;
/**
 * 我们给接口加@Repository注解，会根据我们的MapperScanner配置，
 *将来会自动为该接口构建匿名实现类，然后实例化这个实现类的对象拿去使用
 * 而实现类的具体方法功能怎么实现，由两方面决定:
 * 1.UserDao.xml   2.interface UserDao中的注解
 */
@Repository
public interface UserDao {
    //演示常用查询
    @Select("select * from user where uid=#{uid}")
    public User findUserByUID(int uid);

    @Select("select * from user where username=#{username} and userage=#{userage}")
    public User findUserByNameAndAge(@Param("username") String username, @Param("userage")int age);

    @Select("select count(*) from user")
    public Integer queryUserCount();

    //演示insert ，并且获取自动递增的id赋值
    @Insert("insert into user(username,userage,usersalary,regTime) values(#{username},#{userage},#{usersalary},#{regTime})")
    @SelectKey(keyProperty = "uid",keyColumn = "uid",resultType = Integer.class,before = false,statement = "select last_insert_id()")
    public void testaddUser1(User user);

    //演示insert ，并且获取自动设置UUID
    @Insert("insert into user2(uid,username,userage,usersalary,regTime) values(#{uid},#{username},#{userage},#{usersalary},#{regTime})")
    @SelectKey(keyProperty = "uid",keyColumn = "uid",resultType = String.class,before = true,statement = "select uuid()")
    public void testaddUser2(User2 user);

    //演示删除
    @Delete("delete from user where uid=#{uid}")
    public void testDeleteUser(int uid);
    //演示更新某个字段
    @Update("update user set username=#{username} where uid=#{uid}")
    public void testUpdateUser1(@Param("uid") int uid,@Param("username")String username);

   //演示ResultMap
    @Select("select * from user where uid=#{uid}")
//    @ResultMap("userMap")
    @Results({@Result(property = "username111",column = "username")})
    public User testReusltRM(int uid);

//演示list
    @Select("<script>" +
            "SELECT * FROM user WHERE uid IN\n" +
            "<foreach collection=\"list\" open=\"(\" close=\")\" separator=\",\" item=\"uid\">\n" +
            "    #{uid}\n" +
            "</foreach>"+
            "</script>")
    public List<User> findUsersByIDs(List<Integer> uids);

//演示list2，基于自定义SQL来做
    @Select("SELECT * FROM user WHERE uid IN list:#{uids}")
    @Lang(SelectInLangDriver.class)
    public List<User> findUsersByIDs3(@Param("uids") List<Integer> uids);

//演示list3，基于自定义SQL来做，能够支持多个集合
    @Select("SELECT * FROM user WHERE uid IN list:#{uids} or userage IN list:#{ages}")
    @Lang(SelectInLangDriver2.class)
    public List<User> findUsersByIDs4(@Param("uids") List<Integer> uids,@Param("ages") List<Integer> ages);
}