mybatis快速入门(四)

package cn.my.mybatis.entity;

public class UserQueryVo {

    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}

<!-- 入参类型是包装类 -->
    <select id="findByNameAndSex" parameterType="cn.my.mybatis.entity.UserQueryVo" resultType="cn.my.mybatis.entity.User">
        select * from user 
        <!-- where标签可以去掉首个and ，sql动态标签和jstl标签很类似，大家看一下应该就差不多了 -->
        <where>
            <if test="user != null">
                <if test="user.sex != null and user.sex != ‘‘">
                    and sex=#{user.sex} 
                </if>
                <if test="user.username != null and user.username != ‘‘">
                    and username=#{user.username}
                </if>
            </if>
        </where>
    </select>

public List<User> findByNameAndSex(UserQueryVo userVo);

 /**
     * 根据名称和sex查询
     */
    @Test 
    public void testFindByNameAndSex(){
           SqlSession session = factory.openSession();
           UserDaoMapper dao = session.getMapper(UserDaoMapper.class);//获取mybatis的动态代码实现接口对象
           //这里就是构建包装类
           UserQueryVo userQueryVo = new UserQueryVo();
           User user = new User();
           user.setUsername("王小二");
           user.setSex("男");
           userQueryVo.setUser(user);
           
           List<User> list = dao.findByNameAndSex(userQueryVo); 
           session.commit();
           session.close();  
           System.out.println(list);
    }
        

  <!-- 入参类型是包装类 -->
    <select id="findByIds" parameterType="cn.my.mybatis.entity.UserQueryVo" resultType="cn.my.mybatis.entity.User">
        select * from user 
        <!-- where标签可以去掉首个and ，sql动态标签和jstl标签很类似，大家看一下应该就差不多了 -->
        <where>
            <if test="listIds != null">
                collection:UserQueryVo的属性名，item表示临时名称下面使用的，open：拼接字符串的开始，close拼接字符串的结束，separator：分隔符
                <foreach collection="listIds" item="id" open=" id in (" close=")" separator=",">
                    #{id}
                </foreach>
            </if>
        </where>
    </select>

public List<User> findByIds(UserQueryVo userVo);

  @Test 
    public void testFindByIds(){
        SqlSession session = factory.openSession();
        UserDaoMapper dao = session.getMapper(UserDaoMapper.class);//获取mybatis的动态代码实现接口对象
        //这里就是构建包装类
        UserQueryVo userQueryVo = new UserQueryVo();
        List<Integer> ids = new ArrayList<Integer>();
        ids.add(1);
        ids.add(10);
        ids.add(22);
        userQueryVo.setListIds(ids);
        
        List<User> list = dao.findByIds(userQueryVo); 
        session.commit();
        session.close();  
        for (User user : list) {
            System.out.println(user);
        }
    }

select * from user WHERE id in ( ? , ? , ? ) 

<?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="cn.my.dao.UserDaoMapper">
    <select id="findById" parameterType="int" resultType="cn.my.mybatis.entity.User">
        select * from user where id=#{id}
    </select>
    
    <!-- sql片段 -->
    <sql id="byNameAndSex_where">
        <if test="user != null">
                <if test="user.sex != null and user.sex != ‘‘">
                    and sex=#{user.sex} 
                </if>
                <if test="user.username != null and user.username != ‘‘">
                    and username=#{user.username}
                </if>
        </if>
    </sql>
    
    <!-- 入参类型是包装类 -->
    <select id="findByNameAndSex" parameterType="cn.my.mybatis.entity.UserQueryVo" resultType="cn.my.mybatis.entity.User">
        select * from user 
        <!-- where标签可以去掉首个and ，sql动态标签和jstl标签很类似，大家看一下应该就差不多了 -->
        <where>
            <!-- 将原有的代码直接写进sql标签中就搞定，如果sql片段在其它xml文件中那么直接引入其它文件的sql片段路径即可 -->
            <include refid="byNameAndSex_where"/>
        </where>
    </select>
    
    <!-- sql片段 -->
    <sql id="byIds_where">
           <if test="listIds != null">
            <!-- collection:UserQueryVo的属性名，item表示临时名称下面使用的，open：拼接字符串的开始，close拼接字符串的结束，separator：分隔符 -->
            <foreach collection="listIds" item="id" open=" id in (" close=")" separator=",">
                #{id}
            </foreach>
        </if>
    </sql>
    
    <!-- 入参类型是包装类 -->
    <select id="findByIds" parameterType="cn.my.mybatis.entity.UserQueryVo" resultType="cn.my.mybatis.entity.User">
        select * from user 
        <!-- where标签可以去掉首个and ，sql动态标签和jstl标签很类似，大家看一下应该就差不多了 -->
        <where>
            <!-- 将原有的代码直接写进sql标签中就搞定，如果sql片段在其它xml文件中那么直接引入其它文件的sql片段路径即可 -->
            <include refid="byIds_where"/>
        </where>
    </select>
    
    <!-- 新增映射 修改id名称为了以后封装basedao-->
    <insert id="insert" parameterType="cn.my.mybatis.entity.User">
         <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
            SELECT LAST_INSERT_ID()
        </selectKey>
        INSERT INTO `user` (`username`,`birthday`,`sex`,`address`) 
        VALUES(#{username},#{birthday},#{sex},#{address})
    </insert>
   
    <!-- 修改用户 修改id名称为了以后封装basedao-->
    <update id="update" parameterType="cn.my.mybatis.entity.User">
        UPDATE `user` 
        SET
          `username` = #{username},
          `birthday` = #{birthday},
          `sex` = #{sex},
          `address` = #{address} 
        WHERE `id` = #{id} ;
    </update>
    <!-- 删除 修改id名称为了以后封装basedao -->
    <delete id="delete" parameterType="java.lang.Integer">
        delete from user where id=#{id}
    </delete>
</mapper>