Two ways to write auto-increment id when adding new data in MyBatis

Two ways to write auto-increment id when adding new data in MyBatis

1. Single insertion

• Interface method:

    public interface PlayerDao {
        int insertOnePlayer(Player player);
        int insertOnePlayer2(Player player);
    }

1.1 Method 1

   public void testInsertGenerateId1() throws IOException {
           // 2. Get sqlSession
           SqlSession sqlSession = sqlSessionFactory.openSession();
           // 3. Get the corresponding mapper
           PlayerDao mapper = sqlSession.getMapper(PlayerDao.class);
           // 4. Execute the query statement and return the result
           Player player = new Player();
           player.setPlayName("Allen Iverson");
           player.setPlayNo(3);
           player.setTeam("76ers");
           player.setHeight(1.83F);
           mapper.insertOnePlayer(player);
           sqlSession.commit();
           System.out.println(player.getId());
       }

• Mapper file:

      <insert id="insertOnePlayer" parameterType="Player" useGeneratedKeys="true" keyProperty="id">
     		insert into tb_player (id, playName, playNo,team, height)
     		values (
                 #{id,jdbcType=INTEGER},
                 #{playName,jdbcType=VARCHAR},
                 #{playNo,jdbcType=INTEGER},
                 #{team,jdbcType=VARCHAR},
                 #{height,jdbcType=DECIMAL}
     		)
     	</insert>

• Method 1 configuration: useGeneratedKeys="true" keyProperty="id"

1.2 Method 2

    public void testInsertGenerateId2() throws IOException {
            // 2. Get sqlSession
            SqlSession sqlSession = sqlSessionFactory.openSession();
            // 3. Get the corresponding mapper
            PlayerDao mapper = sqlSession.getMapper(PlayerDao.class);
            // 4. Execute the query statement and return the result
            Player player = new Player();
            player.setPlayName("Tony Parker");
            player.setPlayNo(9);
            player.setTeam("spurs");
            player.setHeight(1.88F);
            mapper.insertOnePlayer2(player);
            sqlSession.commit();
            System.out.println(player.getId());
        }Mapper file:<insert id="insertOnePlayer2" parameterType="Player">
           <selectKey  keyProperty="id" order="AFTER" resultType="int">
               select LAST_INSERT_ID()
           </selectKey>
           insert into tb_player (id, playName, playNo,team, height)
           values (
           #{id,jdbcType=INTEGER},
           #{playName,jdbcType=VARCHAR},
           #{playNo,jdbcType=INTEGER},
           #{team,jdbcType=VARCHAR},
           #{height,jdbcType=DECIMAL}
           )
       </insert>

• Method 2 is completed through the selectKey tag. SelectKey is more flexible and supports a certain degree of customization.

2. Batch insertion

• The Java file is omitted, and the Mapper file is given here directly. The Mapper file is as follows, which is actually: useGeneratedKeys="true" keyProperty="id", where id is the primary key id of JavaBean

  <insert id="insertBatch" parameterType="" useGeneratedKeys="true" keyProperty="id">
   INSERT INTO partition_info (id, node_ip_id, init_schema_info_id,
   prefix_table_index, partition_num, start_time,
   end_time, create_time, is_delete
   )
   values
   <foreach collection="list" item="item" index="index" separator=",">
     (#{,jdbcType=INTEGER}, #{,jdbcType=INTEGER}, #{,jdbcType=INTEGER},
     #{,jdbcType=VARCHAR}, #{,jdbcType=VARCHAR}, #{,jdbcType=TIMESTAMP},
     #{,jdbcType=TIMESTAMP}, #{,jdbcType=TIMESTAMP}, #{,jdbcType=TINYINT}
     )
   </foreach>
 </insert>

• Java code

        System.out.println("before insert ...");
        for (PartitionInfo p: list) {
            System.out.println(p);
        }

        PartitionInfoMapper mapper = sqlSession.getMapper(PartitionInfoMapper.class);
        int i = mapper.insertBatch(list);
        System.out.println("The rows be affected :" + i);

        System.out.println("after insert ...");
        for (PartitionInfo p: list) {
            System.out.println(p);
        }

• Output

before insert ...
PartitionInfo(id=null, nodeIpId=1, initSchemaInfoId=1, prefixTableIndex=1, partitionNum=null, startTime=null, endTime=null, createTime=Fri Dec 13 18:26:46 CST 2019, isDelete=null)
PartitionInfo(id=null, nodeIpId=2, initSchemaInfoId=2, prefixTableIndex=2, partitionNum=null, startTime=null, endTime=null, createTime=Fri Dec 13 18:26:46 CST 2019, isDelete=null)
PartitionInfo(id=null, nodeIpId=3, initSchemaInfoId=3, prefixTableIndex=3, partitionNum=null, startTime=null, endTime=null, createTime=Fri Dec 13 18:26:46 CST 2019, isDelete=null)
The rows be affected :3
after insert ...
PartitionInfo(id=701, nodeIpId=1, initSchemaInfoId=1, prefixTableIndex=1, partitionNum=null, startTime=null, endTime=null, createTime=Fri Dec 13 18:26:46 CST 2019, isDelete=null)
PartitionInfo(id=702, nodeIpId=2, initSchemaInfoId=2, prefixTableIndex=2, partitionNum=null, startTime=null, endTime=null, createTime=Fri Dec 13 18:26:46 CST 2019, isDelete=null)
PartitionInfo(id=703, nodeIpId=3, initSchemaInfoId=3, prefixTableIndex=3, partitionNum=null, startTime=null, endTime=null, createTime=Fri Dec 13 18:26:46 CST 2019, isDelete=null)

• All other codes here are omitted, basically: useGeneratedKeys="true" keyProperty="id" These two tags work
• In addition, the version of mybatis I use is 3.4.1

3. Pay attention

• Note the insert into tb_player (id, playName, playNo, team, height) in the Mapper file. Don't add a comma here. There is a comma after the height before, causing the error of the pointer to be null.