MyBatis批量插入

普通for循环#

@Test
public void testInsertBatch2() throws Exception {
    long start = System.currentTimeMillis();
    User user;
    SqlSession sqlSession = sqlSessionTemplate.getSqlSessionFactory().openSession(false);
    UserDao mapper = sqlSession.getMapper(UserDao.class);
    for (int i = 0; i < 500; i++) {
        user = new User();
        user.setId("test" + i);
        user.setName("name" + i);
        user.setDelFlag("0");
        mapper.insert(user);
    }
    sqlSession.commit();
    long end = System.currentTimeMillis();
    System.out.println("---------------" + (start - end) + "---------------");
}

myBatis的BATCH模式插入#

@Test
public void testInsertBatch2() throws Exception {
    long start = System.currentTimeMillis();
    User user;
    SqlSession sqlSession = sqlSessionTemplate.getSqlSessionFactory().openSession(ExecutorType.BATCH, false);
    UserDao mapper = sqlSession.getMapper(UserDao.class);
    for (int i = 0; i < 500; i++) {
        user = new User();
        user.setId("test" + i);
        user.setName("name" + i);
        user.setDelFlag("0");
        mapper.insert(user);
    }
    sqlSession.commit();
    long end = System.currentTimeMillis();
    System.out.println("---------------" + (start - end) + "---------------");
}

前两种的xml配置#

<insert id="insert">
    INSERT INTO t_user (id, name, del_flag)
          VALUES(#{id}, #{name}, #{delFlag})
</insert>

foreach方式插入#

@Test
public void testInsertBatch() throws Exception {
    long start = System.currentTimeMillis();
    List<User> list = new ArrayList<>();
    User user;
    for (int i = 0; i < 10000; i++) {
        user = new User();
        user.setId("test" + i);
        user.setName("name" + i);
        user.setDelFlag("0");
        list.add(user);
    }
    userService.insertBatch(list);
    long end = System.currentTimeMillis();
    System.out.println("---------------" + (start - end) + "---------------");
}

xml配置#

<insert id="insertBatch">
    INSERT INTO t_user
            (id, name, del_flag)
    VALUES
    <foreach collection ="list" item="user" separator =",">
         (#{user.id}, #{user.name}, #{user.delFlag})
    </foreach >
</insert>

batch相对来说比simple快，第三种批量写入是最快的，但第三种会产生问题#

mysql默认接受sql的大小是1048576(1M)，即第三种方式若数据量超过1M会报如下异常

nested exception is com.mysql.jdbc.PacketTooBigException: Packet for query is too large (5677854 > 1048576).

You can change this value on the server by setting the max_allowed_packet' variable.

可通过调整MySQL安装目录下的my.ini文件中[mysqld]段的＂max_allowed_packet = 1M＂

executorType#

• simple，不做特殊事情
• reuse，缓存起来复用
• batch，批量方式

batch方式最快

mapper不过是通过sqlfactory自动实现了原始dao接口和dao实现类

写好配置，连接池，预处理语句，然后调用执行即可