这篇文章主要介绍了MyBatis的批量查询方法有哪些的相关知识，内容详细易懂，操作简单快捷，具有一定借鉴价值，相信大家阅读完这篇MyBatis的批量查询方法有哪些文章都会有所收获，下面我们一起来看看吧。
一.直接循环插入
@RestController
@RequestMapping("/mybatis3/user")
@RequiredArgsConstructor
public class UserController {
private final IUserService iUserService;
@GetMapping("/one")
public Long one(){
return iUserService.add();
}
}
Long add();
@Service
@RequiredArgsConstructor
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {
private final UserMapper userMapper;
@Override
public Long add() {
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("耗时："+( end - start ) + "ms");
return (end-start);
}
}
Integer insertUsers(User user);
<insert id="insertUsers" >
insert into user(username,password)
values (#{username}, #{password})
</insert>最终耗时：14s多
二.关闭MySql自动提交，手动进行循环插入提交
@RestController
@RequestMapping("/mybatis3/user")
@RequiredArgsConstructor
public class UserController {
private final IUserService iUserService;
@GetMapping("/one")
public Long one(){
return iUserService.add();
}
}
Long add2();
@Service
@RequiredArgsConstructor
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {
private final UserMapper userMapper;
// 手动开启sql的批量提交
private final SqlSessionTemplate sqlSessionTemplate;
@Override
public Long add2(){
//关闭自动提交
SqlSession sqlSession = sqlSessionTemplate.getSqlSessionFactory().openSession(ExecutorType.BATCH, false);
UserMapper mapper = 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);
mapper.insertUsers(user);
}
//自动提交SQL
sqlSession.commit();
long end = System.currentTimeMillis();
System.out.println("耗时："+( end - start ) + "ms");
return (end-start);
}
}平均：0.12s
第三种：用List集合的方式插入数据库（推荐）
@RestController
@RequestMapping("/mybatis3/user")
@RequiredArgsConstructor
public class UserController {
private final IUserService iUserService;
@GetMapping("/one3")
public Long one3(){
return iUserService.add3();
}
}
Long add3();
@Service
@RequiredArgsConstructor
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {
private final UserMapper userMapper;
@Override
public Long add3(){
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.insertUsersThree(userList);
long end = System.currentTimeMillis();
System.out.println("耗时："+( end - start ) + "ms");
return (end-start);
}
}
Integer insertUsersThree(List<User> userList);
<insert id="insertUsersThree">
insert into user(username,password)
values
<foreach collection="userList" item="user" separator=",">
(#{user.username},#{user.password})
</foreach>
</insert>第四种: MyBatis-Plus提供的SaveBatch方法
@RestController
@RequestMapping("/mybatis3/user")
@RequiredArgsConstructor
public class UserController {
private final IUserService iUserService;
@GetMapping("/one4")
public Long one4(){
return iUserService.add4();
}
}
Long add4();
@Service
@RequiredArgsConstructor
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {
private final UserMapper userMapper;
@Override
public Long add4() {
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("耗时："+( end - start ) + "ms");
return (end-start);
}
}直接报错：
看报错信息：
长串：Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: com.huang.mybatis3.mapper.UserMapper.insert (batch index #1) failed. Cause: java.sql.BatchUpdateException: Data truncation: Out of range value for column ‘id’ at row 1
; Data truncation: Out of range value for column ‘id’ at row 1; nested exception is java.sql.BatchUpdateException: Data truncation: Out of range value for column ‘id’ at row 1] with root cause短串：Data truncation: Out of range value for column ‘id’ at row 1
翻译一下：
可以发现就是我们的id超出范围：
int类型改为bigint即可
故此我们可以得出一个结论：设置数据库id的时候设置为bigint还是蛮好的哈
平均时间：0.2s
第五种 MyBatis-Plus提供的InsertBatchSomeColumn方法（推荐）
InsertBatchSomeColumn方法了解
这个类的注解就写的很明白
扩展这个InsertBatchSomeColumn方法
@Slf4j
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));
log.info("扩展的getMethodList方法被框架调用了");
return methodList;
}
}扩展的方法注入bean容器
/**
* @author Stone
* @date 2023/1/3
* @apiNote
*/
@Configuration
public class MybatisPlusConfig {
@Bean
public EasySqlInjector sqlInjector(){
return new EasySqlInjector();
}
}创建一个Mapper去实现我们的扩展的飞方法
public interface EasySqlInjectMapper<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);
}业务层
@Override
public Long add5() {
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("耗时："+( end - start ) + "ms");
return (end-start);
}耗时： 0.2 s
