Implementing Batch Insert with MyBatis-Plus in Java

When reviewing code, the author discovered that inserting records inside a for loop creates a new database connection for each iteration, which dramatically reduces performance even though the final result is unchanged. The article uses a delivery‑analogy to illustrate why batch insertion is far more efficient.

The solution is to use MyBatis‑Plus (MP) and its saveBatch method to insert many rows in a single operation. The article walks through the complete implementation steps.

1. Add MP dependency

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>mybatis-plus-latest-version</version>
</dependency>

Replace mybatis-plus-latest-version with the actual version number (e.g., 3.4.3).

2. Create database and table

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
DROP DATABASE IF EXISTS `testdb`;
CREATE DATABASE `testdb`;
USE `testdb`;

DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NULL DEFAULT NULL,
  `password` varchar(255) NULL DEFAULT NULL,
  `createtime` datetime NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=6 CHARSET=utf8mb4;

INSERT INTO `user` VALUES (1,'赵云','123456','2021-09-10 18:11:16');
INSERT INTO `user` VALUES (2,'张飞','123456','2021-09-10 18:11:28');
INSERT INTO `user` VALUES (3,'关羽','123456','2021-09-10 18:11:34');
INSERT INTO `user` VALUES (4,'刘备','123456','2021-09-10 18:11:41');
INSERT INTO `user` VALUES (5,'曹操','123456','2021-09-10 18:12:02');
SET FOREIGN_KEY_CHECKS = 1;

3. Entity class

import lombok.Getter;
import lombok.Setter;
import java.util.Date;

@Getter
@Setter
public class User {
    private int id;
    private String name;
    private String password;
    private Date createtime;
}

4. Controller layer

import com.example.demo.model.User;
import com.example.demo.service.impl.UserServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.ArrayList;
import java.util.List;

@RestController
@RequestMapping("/u")
public class UserController {
    @Autowired
    private UserServiceImpl userService;

    /** MP batch insert */
    @RequestMapping("/savebatch")
    public boolean saveBatch() {
        List<User> list = new ArrayList<>();
        // prepare 1000 users
        for (int i = 0; i < 1000; i++) {
            User user = new User();
            user.setName("test:" + i);
            user.setPassword("123456");
            list.add(user);
        }
        // batch insert
        return userService.saveBatch(list);
    }
}

5. Service layer

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.demo.model.User;

public interface UserService extends IService<User> {
}

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.demo.mapper.UserMapper;
import com.example.demo.model.User;
import com.example.demo.service.UserService;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
}

6. Mapper layer

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.model.User;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface UserMapper extends BaseMapper<User> {
}

The article concludes that using MP’s saveBatch dramatically reduces the number of database round‑trips, improving performance. It also hints at a future discussion of native JDBC batch inserts and a comparison of the two approaches.