【Mybatis】深入浅出Mybatis（十二）——逆向工程后增删改查调用

朴灿烈づ我的快乐病毒、 2022-06-12 00:36 220阅读 0赞

# 一、前言 #

在前一篇博客中，小编曾经向大家分享了[【Mybatis】深入浅出Mybatis（十）——逆向工程][Mybatis_Mybatis]，简单介绍了如何通过逆向工程，生成我们需要的实体和mapper映射文件。在这篇博客中，小编将向大家介绍一下如何调用。

# 二、增删改查 #

我们对一个表进行相应得到增删改查，首先看一下mapper映射文件：

## 2.1 mapper映射 ##

<?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.taotao.mapper.TbContentMapper" >
      <resultMap id="BaseResultMap" type="com.taotao.pojo.TbContent" >
        <id column="id" property="id" jdbcType="BIGINT" />
        <result column="category_id" property="categoryId" jdbcType="BIGINT" />
        <result column="title" property="title" jdbcType="VARCHAR" />
        <result column="sub_title" property="subTitle" jdbcType="VARCHAR" />
        <result column="title_desc" property="titleDesc" jdbcType="VARCHAR" />
        <result column="url" property="url" jdbcType="VARCHAR" />
        <result column="pic" property="pic" jdbcType="VARCHAR" />
        <result column="pic2" property="pic2" jdbcType="VARCHAR" />
        <result column="created" property="created" jdbcType="TIMESTAMP" />
        <result column="updated" property="updated" jdbcType="TIMESTAMP" />
      </resultMap>
      <resultMap id="ResultMapWithBLOBs" type="com.taotao.pojo.TbContent" extends="BaseResultMap" >
        <result column="content" property="content" jdbcType="LONGVARCHAR" />
      </resultMap>
      <sql id="Example_Where_Clause" >
        <where >
          <foreach collection="oredCriteria" item="criteria" separator="or" >
            <if test="criteria.valid" >
              <trim prefix="(" suffix=")" prefixOverrides="and" >
                <foreach collection="criteria.criteria" item="criterion" >
                  <choose >
                    <when test="criterion.noValue" >
                      and ${criterion.condition}
                    </when>
                    <when test="criterion.singleValue" >
                      and ${criterion.condition} #{criterion.value}
                    </when>
                    <when test="criterion.betweenValue" >
                      and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                    </when>
                    <when test="criterion.listValue" >
                      and ${criterion.condition}
                      <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                        #{listItem}
                      </foreach>
                    </when>
                  </choose>
                </foreach>
              </trim>
            </if>
          </foreach>
        </where>
      </sql>
      <sql id="Update_By_Example_Where_Clause" >
        <where >
          <foreach collection="example.oredCriteria" item="criteria" separator="or" >
            <if test="criteria.valid" >
              <trim prefix="(" suffix=")" prefixOverrides="and" >
                <foreach collection="criteria.criteria" item="criterion" >
                  <choose >
                    <when test="criterion.noValue" >
                      and ${criterion.condition}
                    </when>
                    <when test="criterion.singleValue" >
                      and ${criterion.condition} #{criterion.value}
                    </when>
                    <when test="criterion.betweenValue" >
                      and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                    </when>
                    <when test="criterion.listValue" >
                      and ${criterion.condition}
                      <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                        #{listItem}
                      </foreach>
                    </when>
                  </choose>
                </foreach>
              </trim>
            </if>
          </foreach>
        </where>
      </sql>
      <sql id="Base_Column_List" >
        id, category_id, title, sub_title, title_desc, url, pic, pic2, created, updated
      </sql>
      <sql id="Blob_Column_List" >
        content
      </sql>
      <select id="selectByExampleWithBLOBs" resultMap="ResultMapWithBLOBs" parameterType="com.taotao.pojo.TbContentExample" >
        select
        <if test="distinct" >
          distinct
        </if>
        <include refid="Base_Column_List" />
        ,
        <include refid="Blob_Column_List" />
        from tb_content
        <if test="_parameter != null" >
          <include refid="Example_Where_Clause" />
        </if>
        <if test="orderByClause != null" >
          order by ${orderByClause}
        </if>
      </select>
      <select id="selectByExample" resultMap="BaseResultMap" parameterType="com.taotao.pojo.TbContentExample" >
        select
        <if test="distinct" >
          distinct
        </if>
        <include refid="Base_Column_List" />
        from tb_content
        <if test="_parameter != null" >
          <include refid="Example_Where_Clause" />
        </if>
        <if test="orderByClause != null" >
          order by ${orderByClause}
        </if>
      </select>
      <select id="selectByPrimaryKey" resultMap="ResultMapWithBLOBs" parameterType="java.lang.Long" >
        select 
        <include refid="Base_Column_List" />
        ,
        <include refid="Blob_Column_List" />
        from tb_content
        where id = #{id,jdbcType=BIGINT}
      </select>
      <delete id="deleteByPrimaryKey" parameterType="java.lang.Long" >
        delete from tb_content
        where id = #{id,jdbcType=BIGINT}
      </delete>
      <delete id="deleteByExample" parameterType="com.taotao.pojo.TbContentExample" >
        delete from tb_content
        <if test="_parameter != null" >
          <include refid="Example_Where_Clause" />
        </if>
      </delete>
      <insert id="insert" parameterType="com.taotao.pojo.TbContent" >
        insert into tb_content (id, category_id, title, 
          sub_title, title_desc, url, 
          pic, pic2, created, 
          updated, content)
        values (#{id,jdbcType=BIGINT}, #{categoryId,jdbcType=BIGINT}, #{title,jdbcType=VARCHAR}, 
          #{subTitle,jdbcType=VARCHAR}, #{titleDesc,jdbcType=VARCHAR}, #{url,jdbcType=VARCHAR}, 
          #{pic,jdbcType=VARCHAR}, #{pic2,jdbcType=VARCHAR}, #{created,jdbcType=TIMESTAMP}, 
          #{updated,jdbcType=TIMESTAMP}, #{content,jdbcType=LONGVARCHAR})
      </insert>
      <insert id="insertSelective" parameterType="com.taotao.pojo.TbContent" >
        insert into tb_content
        <trim prefix="(" suffix=")" suffixOverrides="," >
          <if test="id != null" >
            id,
          </if>
          <if test="categoryId != null" >
            category_id,
          </if>
          <if test="title != null" >
            title,
          </if>
          <if test="subTitle != null" >
            sub_title,
          </if>
          <if test="titleDesc != null" >
            title_desc,
          </if>
          <if test="url != null" >
            url,
          </if>
          <if test="pic != null" >
            pic,
          </if>
          <if test="pic2 != null" >
            pic2,
          </if>
          <if test="created != null" >
            created,
          </if>
          <if test="updated != null" >
            updated,
          </if>
          <if test="content != null" >
            content,
          </if>
        </trim>
        <trim prefix="values (" suffix=")" suffixOverrides="," >
          <if test="id != null" >
            #{id,jdbcType=BIGINT},
          </if>
          <if test="categoryId != null" >
            #{categoryId,jdbcType=BIGINT},
          </if>
          <if test="title != null" >
            #{title,jdbcType=VARCHAR},
          </if>
          <if test="subTitle != null" >
            #{subTitle,jdbcType=VARCHAR},
          </if>
          <if test="titleDesc != null" >
            #{titleDesc,jdbcType=VARCHAR},
          </if>
          <if test="url != null" >
            #{url,jdbcType=VARCHAR},
          </if>
          <if test="pic != null" >
            #{pic,jdbcType=VARCHAR},
          </if>
          <if test="pic2 != null" >
            #{pic2,jdbcType=VARCHAR},
          </if>
          <if test="created != null" >
            #{created,jdbcType=TIMESTAMP},
          </if>
          <if test="updated != null" >
            #{updated,jdbcType=TIMESTAMP},
          </if>
          <if test="content != null" >
            #{content,jdbcType=LONGVARCHAR},
          </if>
        </trim>
      </insert>
      <select id="countByExample" parameterType="com.taotao.pojo.TbContentExample" resultType="java.lang.Integer" >
        select count(*) from tb_content
        <if test="_parameter != null" >
          <include refid="Example_Where_Clause" />
        </if>
      </select>
      <update id="updateByExampleSelective" parameterType="map" >
        update tb_content
        <set >
          <if test="record.id != null" >
            id = #{record.id,jdbcType=BIGINT},
          </if>
          <if test="record.categoryId != null" >
            category_id = #{record.categoryId,jdbcType=BIGINT},
          </if>
          <if test="record.title != null" >
            title = #{record.title,jdbcType=VARCHAR},
          </if>
          <if test="record.subTitle != null" >
            sub_title = #{record.subTitle,jdbcType=VARCHAR},
          </if>
          <if test="record.titleDesc != null" >
            title_desc = #{record.titleDesc,jdbcType=VARCHAR},
          </if>
          <if test="record.url != null" >
            url = #{record.url,jdbcType=VARCHAR},
          </if>
          <if test="record.pic != null" >
            pic = #{record.pic,jdbcType=VARCHAR},
          </if>
          <if test="record.pic2 != null" >
            pic2 = #{record.pic2,jdbcType=VARCHAR},
          </if>
          <if test="record.created != null" >
            created = #{record.created,jdbcType=TIMESTAMP},
          </if>
          <if test="record.updated != null" >
            updated = #{record.updated,jdbcType=TIMESTAMP},
          </if>
          <if test="record.content != null" >
            content = #{record.content,jdbcType=LONGVARCHAR},
          </if>
        </set>
        <if test="_parameter != null" >
          <include refid="Update_By_Example_Where_Clause" />
        </if>
      </update>
      <update id="updateByExampleWithBLOBs" parameterType="map" >
        update tb_content
        set id = #{record.id,jdbcType=BIGINT},
          category_id = #{record.categoryId,jdbcType=BIGINT},
          title = #{record.title,jdbcType=VARCHAR},
          sub_title = #{record.subTitle,jdbcType=VARCHAR},
          title_desc = #{record.titleDesc,jdbcType=VARCHAR},
          url = #{record.url,jdbcType=VARCHAR},
          pic = #{record.pic,jdbcType=VARCHAR},
          pic2 = #{record.pic2,jdbcType=VARCHAR},
          created = #{record.created,jdbcType=TIMESTAMP},
          updated = #{record.updated,jdbcType=TIMESTAMP},
          content = #{record.content,jdbcType=LONGVARCHAR}
        <if test="_parameter != null" >
          <include refid="Update_By_Example_Where_Clause" />
        </if>
      </update>
      <update id="updateByExample" parameterType="map" >
        update tb_content
        set id = #{record.id,jdbcType=BIGINT},
          category_id = #{record.categoryId,jdbcType=BIGINT},
          title = #{record.title,jdbcType=VARCHAR},
          sub_title = #{record.subTitle,jdbcType=VARCHAR},
          title_desc = #{record.titleDesc,jdbcType=VARCHAR},
          url = #{record.url,jdbcType=VARCHAR},
          pic = #{record.pic,jdbcType=VARCHAR},
          pic2 = #{record.pic2,jdbcType=VARCHAR},
          created = #{record.created,jdbcType=TIMESTAMP},
          updated = #{record.updated,jdbcType=TIMESTAMP}
        <if test="_parameter != null" >
          <include refid="Update_By_Example_Where_Clause" />
        </if>
      </update>
      <update id="updateByPrimaryKeySelective" parameterType="com.taotao.pojo.TbContent" >
        update tb_content
        <set >
          <if test="categoryId != null" >
            category_id = #{categoryId,jdbcType=BIGINT},
          </if>
          <if test="title != null" >
            title = #{title,jdbcType=VARCHAR},
          </if>
          <if test="subTitle != null" >
            sub_title = #{subTitle,jdbcType=VARCHAR},
          </if>
          <if test="titleDesc != null" >
            title_desc = #{titleDesc,jdbcType=VARCHAR},
          </if>
          <if test="url != null" >
            url = #{url,jdbcType=VARCHAR},
          </if>
          <if test="pic != null" >
            pic = #{pic,jdbcType=VARCHAR},
          </if>
          <if test="pic2 != null" >
            pic2 = #{pic2,jdbcType=VARCHAR},
          </if>
          <if test="created != null" >
            created = #{created,jdbcType=TIMESTAMP},
          </if>
          <if test="updated != null" >
            updated = #{updated,jdbcType=TIMESTAMP},
          </if>
          <if test="content != null" >
            content = #{content,jdbcType=LONGVARCHAR},
          </if>
        </set>
        where id = #{id,jdbcType=BIGINT}
      </update>
      <update id="updateByPrimaryKeyWithBLOBs" parameterType="com.taotao.pojo.TbContent" >
        update tb_content
        set category_id = #{categoryId,jdbcType=BIGINT},
          title = #{title,jdbcType=VARCHAR},
          sub_title = #{subTitle,jdbcType=VARCHAR},
          title_desc = #{titleDesc,jdbcType=VARCHAR},
          url = #{url,jdbcType=VARCHAR},
          pic = #{pic,jdbcType=VARCHAR},
          pic2 = #{pic2,jdbcType=VARCHAR},
          created = #{created,jdbcType=TIMESTAMP},
          updated = #{updated,jdbcType=TIMESTAMP},
          content = #{content,jdbcType=LONGVARCHAR}
        where id = #{id,jdbcType=BIGINT}
      </update>
      <update id="updateByPrimaryKey" parameterType="com.taotao.pojo.TbContent" >
        update tb_content
        set category_id = #{categoryId,jdbcType=BIGINT},
          title = #{title,jdbcType=VARCHAR},
          sub_title = #{subTitle,jdbcType=VARCHAR},
          title_desc = #{titleDesc,jdbcType=VARCHAR},
          url = #{url,jdbcType=VARCHAR},
          pic = #{pic,jdbcType=VARCHAR},
          pic2 = #{pic2,jdbcType=VARCHAR},
          created = #{created,jdbcType=TIMESTAMP},
          updated = #{updated,jdbcType=TIMESTAMP}
        where id = #{id,jdbcType=BIGINT}
      </update>
    </mapper>

在这个文件中，包含了所有的增删改查的方法。它们对应着不同的sql语句，我们要做的就是要选择合适得到语句来执行我们的操作。下面一次展示增删改查操作。

## 2.2 增 ##

在这里我们直接调用dao的insert方法，insert使用的sql语句可以在mapper映射文件中找到。

/** * 内容管理service * @author Ares * */
    @Service
    public class ContentServiceImpl implements ContentService { 
    
        @Autowired
        private TbContentMapper contentMapper;
    
        @Override
        public TaotaoResult insertContent(TbContent content) {
            content.setCreated(new Date());
            content.setUpdated(new Date());
            //插入数据
            contentMapper.insert(content);
    
            return TaotaoResult.ok();
        }
    }

# 2.3 删 #

@Override
        public TaotaoResult deleteContent(Long id) {
            int count = contentMapper.deleteByPrimaryKey(id);
            if (count>0) {
                return TaotaoResult.ok();
            }
            return null;
        }

## 2.4 改 ##

@Override
        public TaotaoResult updateContent(TbContent content) {
            content.setUpdated(new Date());
            //更新数据
            contentMapper.updateByPrimaryKey(content);
            return TaotaoResult.ok();
        }

## 2.5 查 ##

这里我们使用按照条件进行查询，TbContentExample ，通过criteria.andCategoryIdEqualTo(id)来确定，查询条件是CategoryId=id的操作。当然我们还可以采用其他的操作。

@Override
        public List<TbContent> getContentList(Long id) {
            TbContentExample example = new TbContentExample();
            Criteria criteria = example.createCriteria();
            criteria.andCategoryIdEqualTo(id);
            //查询
            List<TbContent> contentList = contentMapper.selectByExample(example);
            return contentList;
        }

# 三、注意事项 #

不知道朋友们有没有发现，我们调用的增删改查都是针对单表操作的，所以这个就是逆向功能的一个弊端吧，如果我们需要进行多表操作，就得对mapper文件进行添加sql，自己写sql语句了。对于这些操作，小编会在下一篇博客中向大家介绍。

# 四、小结 #

逆向工程的的使用还是比较方便的，当我们在使用的过程中，还是有很多的需要进行单表操作的，下面只要我们找到合适的方法，写出合适的方法还是很666的。加油！

[Mybatis_Mybatis]: http://blog.csdn.net/kisscatforever/article/details/61430064