面试题：MyBatis批量插入的五种方式，哪种最强？

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前言

列举了MyBatis和MyBatis-Plus常用的五种批量插入的方式，进行了详细的总结归纳

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一、准备工作

1、导入pom.xml依赖

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

<!--Mybatis依赖-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.2</version>
</dependency>

<!--Mybatis-Plus依赖-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.2</version>
</dependency>

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

2、配置yml文件

server:
  port: 8080
 
spring:
  datasource:
    username: mysql用户名
    password: mysql密码
    url: jdbc:mysql://localhost:3306/数据库名字?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
 
mybatis:
  mapper-locations: classpath:mapping/*.xml

3、公用的User类

@Data
public class User {
 
    private int id;
    private String username;
    private String password;
}

二、MyBatis利用For循环批量插入

1、编写UserService服务类，测试一万条数据耗时情况

@Service
public class UserService {
 
    @Resource
    private UserMapper userMapper;
 
    public void InsertUsers(){
        long start = System.currentTimeMillis();
        for(int i = 0 ;i < 10000; i++) {
            User user = new User();
            user.setUsername("name" + i);
            user.setPassword("password" + i);
            userMapper.insertUsers(user);
        }
        long end = System.currentTimeMillis();
        System.out.println("一万条数据总耗时：" + (end-start) + "ms" );
    }
 
}

2、编写UserMapper接口

@Mapper
public interface UserMapper {
 
    Integer insertUsers(User user);
}

3、编写UserMapper.xml文件

<?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.ithuang.demo.mapper.UserMapper">
    <insert id="insertUsers">
        INSERT INTO user (username, password)
        VALUES(#{username}, #{password})
    </insert>
</mapper>

4、进行单元测试

@SpringBootTest
class DemoApplicationTests {
 
    @Resource
    private UserService userService;
 
    @Test
    public void insert(){
        userService.InsertUsers();
    }
 
}

5、结果输出

一万条数据总耗时：26348ms

三、MyBatis的手动批量提交

1、其他保持不变，Service层作稍微的变化

@Service
public class UserService {
 
    @Resource
    private UserMapper userMapper;
 
    @Resource
    private SqlSessionTemplate sqlSessionTemplate;
 
    public void InsertUsers(){
        //关闭自动提交
        SqlSession sqlSession = sqlSessionTemplate.getSqlSessionFactory().openSession(ExecutorType.BATCH, false);
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        long start = System.currentTimeMillis();
        for(int i = 0 ;i < 10000; i++) {
            User user = new User();
            user.setUsername("name" + i);
            user.setPassword("password" + i);
            userMapper.insertUsers(user);
        }
        sqlSession.commit();
        long end = System.currentTimeMillis();
        System.out.println("一万条数据总耗时：" + (end-start) + "ms" );
    }
 
}

2、结果输出

一万条数据总耗时：24516ms

四、MyBatis以集合方式批量新增（推荐）

1、编写UserService服务类

@Service
public class UserService {
 
    @Resource
    private UserMapper userMapper;
 
    public void InsertUsers(){
        long start = System.currentTimeMillis();
        List<User> userList = new ArrayList<>();
        User user;
        for(int i = 0 ;i < 10000; i++) {
            user = new User();
            user.setUsername("name" + i);
            user.setPassword("password" + i);
            userList.add(user);
        }
        userMapper.insertUsers(userList);
        long end = System.currentTimeMillis();
        System.out.println("一万条数据总耗时：" + (end-start) + "ms" );
    }
 
}

2、编写UserMapper接口

@Mapper
public interface UserMapper {
 
    Integer insertUsers(List<User> userList);
}

3、编写UserMapper.xml文件

<?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.ithuang.demo.mapper.UserMapper">
    <insert id="insertUsers">
        INSERT INTO user (username, password)
        VALUES
        <foreach collection ="userList" item="user" separator =",">
            (#{user.username}, #{user.password})
        </foreach>
    </insert>
</mapper>

4、输出结果

一万条数据总耗时：521ms

五、MyBatis-Plus提供的SaveBatch方法

1、编写UserService服务

@Service
public class UserService extends ServiceImpl<UserMapper, User> implements IService<User> {
 
    public void InsertUsers(){
        long start = System.currentTimeMillis();
        List<User> userList = new ArrayList<>();
        User user;
        for(int i = 0 ;i < 10000; i++) {
            user = new User();
            user.setUsername("name" + i);
            user.setPassword("password" + i);
            userList.add(user);
        }
        saveBatch(userList);
        long end = System.currentTimeMillis();
        System.out.println("一万条数据总耗时：" + (end-start) + "ms" );
    }
}

2、编写UserMapper接口

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

3、单元测试结果

一万条数据总耗时：24674ms

六、MyBatis-Plus提供的InsertBatchSomeColumn方法（推荐）

1、编写EasySqlInjector 自定义类

public class EasySqlInjector extends DefaultSqlInjector {
 
 
    @Override
    public List<AbstractMethod> getMethodList(Class<?> mapperClass, TableInfo tableInfo) {
        // 注意：此SQL注入器继承了DefaultSqlInjector(默认注入器)，调用了DefaultSqlInjector的getMethodList方法，保留了mybatis-plus的自带方法
        List<AbstractMethod> methodList = super.getMethodList(mapperClass, tableInfo);
        methodList.add(new InsertBatchSomeColumn(i -> i.getFieldFill() != FieldFill.UPDATE));
        return methodList;
    }
 
}

2、定义核心配置类注入此Bean

@Configuration
public class MybatisPlusConfig {
 
    @Bean
    public EasySqlInjector sqlInjector() {
        return new EasySqlInjector();
    }
}

3、编写UserService服务类

public class UserService{
 
    @Resource
    private UserMapper userMapper;
    public void InsertUsers(){
        long start = System.currentTimeMillis();
        List<User> userList = new ArrayList<>();
        User user;
        for(int i = 0 ;i < 10000; i++) {
            user = new User();
            user.setUsername("name" + i);
            user.setPassword("password" + i);
            userList.add(user);
        }
        userMapper.insertBatchSomeColumn(userList);
        long end = System.currentTimeMillis();
        System.out.println("一万条数据总耗时：" + (end-start) + "ms" );
    }
}

4、编写EasyBaseMapper接口

public interface EasyBaseMapper<T> extends BaseMapper<T> {
    /**
     * 批量插入 仅适用于mysql
     *
     * @param entityList 实体列表
     * @return 影响行数
     */
    Integer insertBatchSomeColumn(Collection<T> entityList);
}

5、编写UserMapper接口

@Mapper
public interface UserMapper<T> extends EasyBaseMapper<User> {
    
}

6、单元测试结果

一万条数据总耗时：575ms

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总结

以上就是我对目前MyBatis常用的批量插入方法的总结