Mybatis动态sql

<where>假如第一个条件为空，会自动处理第一个and

<!-- =====================根据条件查询================== -->
     <select id="selectPersonByCondition" parameterType="qc" resultMap="BaseResultMapper">
         select * from person_test t
         <where>
             <if test="name != null">
                 t.name like '%${name}%'
             </if>
             <if test="gender != null">
                 and t.gender = #{gender}
             </if>
             <if test="birthday != null">
                 and t.birthday = #{birthday}
             </if>
             <if test="address != null">
                 and t.address like '%${address}%'
             </if>
         </where>
     </select>

<set>会自动解决最后一个,

<update id="updatePerson" parameterType="cn.tx.model.Person">
         update person_test p
         <set>
             <if test="name != null">
                 p.name = #{name},
             </if>
             <if test="gender != null">
                 p.gender = #{gender},
             </if>
             <if test="birthday != null">
                 p.birthday = #{birthday},
             </if>
             <if test="address != null">
                 p.address = #{address},
             </if>
         </set>
         <where>
             p.id = ${id}
         </where>
     </update>

foreach

 <!-- map.put("pids",Integer[] ids)
         collection:需要遍历的集合
         open:开始符号
         close:结束符号
         item:每一项
         separator:分隔符
         index:索引
      -->
     <select id="selectPersonByIn" parameterType="map" resultMap="BaseResultMapper">
         select * from person_test t where t.id in 
         <foreach collection="pids" open="(" close=")" item="id" separator="," index="i">
             #{id}
         </foreach>
     </select>

批量插入与批量删除

<insert id="insertBatch" parameterType="map">
        
        <selectKey keyProperty="personId" order="AFTER" resultType="int">
            select LAST_INSERT_ID()
        </selectKey>
        insert into person (person_id, name, gender, person_addr, birthday)
        values
        <foreach collection="personList" separator="," item="person">
            (#{person.personId}, #{person.name}, #{person.gender}, #{person.personAddr}, #{person.birthday})
        </foreach>
    </insert>

@Test
    public void insertBatch(){
        SqlSession session = sessionFactory.openSession();
        List<Person> pList = new ArrayList<Person>();
        Map<String,Object> map = new HashMap<String,Object>();
        
        try {
            for(int i = 0; i < 1000008; i++){
                Person p = new Person();
                p.setName("黄盖"+i);
                p.setGender(1);
                p.setPersonAddr("北京"+i);
                p.setBirthday(new Date());
                pList.add(p);
                if(i%100 == 0){//防止内存溢出
                    map.put("personList", pList);
                    session.insert("com.rl.mapper.PersonMapper.insertBatch", map);
                    pList.clear();
                }
            }
            map.put("personList", pList);
            session.insert("com.rl.mapper.PersonMapper.insertBatch", map);
        
            
            //数据库的变更都要提交事务
            session.commit();
            
        } catch (Exception e) {
            e.printStackTrace();
            session.rollback();
        }finally{
            session.close();
        }
    }

<delete id="delete" parameterType="map">
        delete from user where user_id in 
        <foreach collection="ids" open="(" close=")" item="userId" separator=",">
            #{userId}
        </foreach>
    </delete>

@Test
    public void deleteBatch(){
        SqlSession session = sessionFactory.openSession();
        List<Integer> idList = new ArrayList<Integer>();
        Map<String,Object> map = new HashMap<String,Object>();
        
        try {
            for(int i = 106; i <= 1000113; i++){
                idList.add(i);
                if(i%100 == 0){
                    map.put("ids", idList);
                    session.delete("com.rl.mapper.PersonMapper.deleteBatch", map);
                    idList.clear();
                }
            }
            map.put("ids", idList);
            session.delete("com.rl.mapper.PersonMapper.deleteBatch", map);
            //数据库的变更都要提交事务
            session.commit();
            
        } catch (Exception e) {
            e.printStackTrace();
            session.rollback();
        }finally{
            session.close();
        }
    }