关于java:给你-2-万条数据怎么快速导入到-MySQL写得太好了

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起源：blog.csdn.net/kisscatforever/article/details/79817039

一、前言

前两天做了一个导入的性能，导入开始的时候十分慢，导入 2w 条数据要 1 分多钟，起初一点一点的优化，从间接把 list 怼进 Mysql 中，到调配把 list 导入 Mysql 中，到多线程把 list 导入 Mysql 中。

工夫是一点一点的变少了。十分的爽，最初变成了 10s 以内。

上面就展现一下过程。

二、间接把 list 怼进 Mysql

应用 mybatis 的批量导入操作：

@Transactional(rollbackFor = Exception.class)
public int addFreshStudentsNew2(List<FreshStudentAndStudentModel> list, String schoolNo) {if (list == null || list.isEmpty()) {return 0;}
    List<StudentEntity> studentEntityList = new LinkedList<>();
    List<EnrollStudentEntity> enrollStudentEntityList = new LinkedList<>();
    List<AllusersEntity> allusersEntityList = new LinkedList<>();

    for (FreshStudentAndStudentModel freshStudentAndStudentModel : list) {EnrollStudentEntity enrollStudentEntity = new EnrollStudentEntity();
        StudentEntity studentEntity = new StudentEntity();
        BeanUtils.copyProperties(freshStudentAndStudentModel, studentEntity);
        BeanUtils.copyProperties(freshStudentAndStudentModel, enrollStudentEntity);
        String operator = TenancyContext.UserID.get();
        String studentId = BaseUuidUtils.base58Uuid();
        enrollStudentEntity.setId(BaseUuidUtils.base58Uuid());
        enrollStudentEntity.setStudentId(studentId);
        enrollStudentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        enrollStudentEntity.setOperator(operator);
        studentEntity.setId(studentId);
        studentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        studentEntity.setOperator(operator);
        studentEntityList.add(studentEntity);
        enrollStudentEntityList.add(enrollStudentEntity);

        AllusersEntity allusersEntity = new AllusersEntity();
        allusersEntity.setId(enrollStudentEntity.getId());
        allusersEntity.setUserCode(enrollStudentEntity.getNemtCode());
        allusersEntity.setUserName(enrollStudentEntity.getName());
        allusersEntity.setSchoolNo(schoolNo);
        allusersEntity.setTelNum(enrollStudentEntity.getTelNum());
        allusersEntity.setPassword(enrollStudentEntity.getNemtCode());  // 明码设置为考生号
        allusersEntityList.add(allusersEntity);
    }
        enResult = enrollStudentDao.insertAll(enrollStudentEntityList);
        stuResult = studentDao.insertAll(studentEntityList);
        allResult = allusersFacade.insertUserList(allusersEntityList);

    if (enResult > 0 && stuResult > 0 && allResult) {return 10;}
    return -10;
}

Mapper.xml

<insert id="insertAll" parameterType="com.dmsdbj.itoo.basicInfo.entity.EnrollStudentEntity">
    insert into tb_enroll_student
    <trim prefix="(" suffix=")" suffixOverrides=",">
            id,  
            remark,  
            nEMT_aspiration,  
            nEMT_code,  
            nEMT_score,  
            student_id,  
            identity_card_id,  
            level,  
            major,  
            name,  
            nation,  
            secondary_college,  
            operator,  
            sex,  
            is_delete,  
            account_address,  
            native_place,  
            original_place,  
            used_name,  
            pictrue,  
            join_party_date,  
            political_status,  
            tel_num,  
            is_registry,  
            graduate_school,  
            create_time,  
            update_time        </trim>        
    values
    <foreach collection="list" item="item" index="index" separator=",">
    (#{item.id,jdbcType=VARCHAR},
            #{item.remark,jdbcType=VARCHAR},
            #{item.nemtAspiration,jdbcType=VARCHAR},
            #{item.nemtCode,jdbcType=VARCHAR},
            #{item.nemtScore,jdbcType=VARCHAR},
            #{item.studentId,jdbcType=VARCHAR},
            #{item.identityCardId,jdbcType=VARCHAR},
            #{item.level,jdbcType=VARCHAR},
            #{item.major,jdbcType=VARCHAR},
            #{item.name,jdbcType=VARCHAR},
            #{item.nation,jdbcType=VARCHAR},
            #{item.secondaryCollege,jdbcType=VARCHAR},
            #{item.operator,jdbcType=VARCHAR},
            #{item.sex,jdbcType=VARCHAR},
            0,
            #{item.accountAddress,jdbcType=VARCHAR},
            #{item.nativePlace,jdbcType=VARCHAR},
            #{item.originalPlace,jdbcType=VARCHAR},
            #{item.usedName,jdbcType=VARCHAR},
            #{item.pictrue,jdbcType=VARCHAR},
            #{item.joinPartyDate,jdbcType=VARCHAR},
            #{item.politicalStatus,jdbcType=VARCHAR},
            #{item.telNum,jdbcType=VARCHAR},
            #{item.isRegistry,jdbcType=TINYINT},
            #{item.graduateSchool,jdbcType=VARCHAR},
            now(),
            now())   
    </foreach>                
</insert>

代码阐明：

底层的 mapper 是通过逆向工程来生成的，批量插入如下，是拼接成相似：insert into tb_enroll_student（）values（），（）…….（）;

这样的毛病是，数据库个别有一个默认的设置，就是每次 sql 操作的数据不能超过 4M。这样插入，数据多的时候，数据库会报错 Packet for query is too large (6071393 > 4194304). You can change this value on the server by setting the max_allowed_packet' variable.， 尽管咱们能够通过

相似 批改 my.ini 加上 max_allowed_packet =67108864，67108864=64M，默认大小 4194304 也就是 4M

批改实现之后要重启 mysql 服务，如果通过命令行批改就不必重启 mysql 服务。

实现本次操作，然而咱们不能保障我的项目单次最大的大小是多少，这样是有弊病的。所以能够思考进行分组导入。

三、分组把 list 导入 Mysql 中

同样实用 mybatis 批量插入，区别是对每次的导入进行分组计算，而后分屡次进行导入：

@Transactional(rollbackFor = Exception.class)
public int addFreshStudentsNew2(List<FreshStudentAndStudentModel> list, String schoolNo) {if (list == null || list.isEmpty()) {return 0;}
    List<StudentEntity> studentEntityList = new LinkedList<>();
    List<EnrollStudentEntity> enrollStudentEntityList = new LinkedList<>();
    List<AllusersEntity> allusersEntityList = new LinkedList<>();

    for (FreshStudentAndStudentModel freshStudentAndStudentModel : list) {EnrollStudentEntity enrollStudentEntity = new EnrollStudentEntity();
        StudentEntity studentEntity = new StudentEntity();
        BeanUtils.copyProperties(freshStudentAndStudentModel, studentEntity);
        BeanUtils.copyProperties(freshStudentAndStudentModel, enrollStudentEntity);
        String operator = TenancyContext.UserID.get();
        String studentId = BaseUuidUtils.base58Uuid();
        enrollStudentEntity.setId(BaseUuidUtils.base58Uuid());
        enrollStudentEntity.setStudentId(studentId);
        enrollStudentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        enrollStudentEntity.setOperator(operator);
        studentEntity.setId(studentId);
        studentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        studentEntity.setOperator(operator);
        studentEntityList.add(studentEntity);
        enrollStudentEntityList.add(enrollStudentEntity);

        AllusersEntity allusersEntity = new AllusersEntity();
        allusersEntity.setId(enrollStudentEntity.getId());
        allusersEntity.setUserCode(enrollStudentEntity.getNemtCode());
        allusersEntity.setUserName(enrollStudentEntity.getName());
        allusersEntity.setSchoolNo(schoolNo);
        allusersEntity.setTelNum(enrollStudentEntity.getTelNum());
        allusersEntity.setPassword(enrollStudentEntity.getNemtCode());  // 明码设置为考生号
        allusersEntityList.add(allusersEntity);
    }

    int c = 100;
    int b = enrollStudentEntityList.size() / c;
    int d = enrollStudentEntityList.size() % c;

    int enResult = 0;
    int stuResult = 0;
    boolean allResult = false;

    for (int e = c; e <= c * b; e = e + c) {enResult = enrollStudentDao.insertAll(enrollStudentEntityList.subList(e - c, e));
        stuResult = studentDao.insertAll(studentEntityList.subList(e - c, e));
        allResult = allusersFacade.insertUserList(allusersEntityList.subList(e - c, e));
    }
    if (d != 0) {enResult = enrollStudentDao.insertAll(enrollStudentEntityList.subList(c * b, enrollStudentEntityList.size()));
        stuResult = studentDao.insertAll(studentEntityList.subList(c * b, studentEntityList.size()));
        allResult = allusersFacade.insertUserList(allusersEntityList.subList(c * b, allusersEntityList.size()));
    }

    if (enResult > 0 && stuResult > 0 && allResult) {return 10;}
    return -10;
}

代码阐明：

这样操作，能够防止下面的谬误，然而分屡次插入，无形中就减少了操作实际，很容易超时。所以这种办法还是不值得提倡的。

再次改良，应用多线程分批导入。

四、多线程分批导入 Mysql

仍然应用 mybatis 的批量导入，不同的是，依据线程数目进行分组，而后再建设多线程池，进行导入。

@Transactional(rollbackFor = Exception.class)
public int addFreshStudentsNew(List<FreshStudentAndStudentModel> list, String schoolNo) {if (list == null || list.isEmpty()) {return 0;}
    List<StudentEntity> studentEntityList = new LinkedList<>();
    List<EnrollStudentEntity> enrollStudentEntityList = new LinkedList<>();
    List<AllusersEntity> allusersEntityList = new LinkedList<>();

    list.forEach(freshStudentAndStudentModel -> {EnrollStudentEntity enrollStudentEntity = new EnrollStudentEntity();
        StudentEntity studentEntity = new StudentEntity();
        BeanUtils.copyProperties(freshStudentAndStudentModel, studentEntity);
        BeanUtils.copyProperties(freshStudentAndStudentModel, enrollStudentEntity);
        String operator = TenancyContext.UserID.get();
        String studentId = BaseUuidUtils.base58Uuid();
        enrollStudentEntity.setId(BaseUuidUtils.base58Uuid());
        enrollStudentEntity.setStudentId(studentId);
        enrollStudentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        enrollStudentEntity.setOperator(operator);
        studentEntity.setId(studentId);
        studentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        studentEntity.setOperator(operator);
        studentEntityList.add(studentEntity);
        enrollStudentEntityList.add(enrollStudentEntity);

        AllusersEntity allusersEntity = new AllusersEntity();
        allusersEntity.setId(enrollStudentEntity.getId());
        allusersEntity.setUserCode(enrollStudentEntity.getNemtCode());
        allusersEntity.setUserName(enrollStudentEntity.getName());
        allusersEntity.setSchoolNo(schoolNo);
        allusersEntity.setTelNum(enrollStudentEntity.getTelNum());
        allusersEntity.setPassword(enrollStudentEntity.getNemtCode());  // 明码设置为考生号
        allusersEntityList.add(allusersEntity);
    });


    int nThreads = 50;

    int size = enrollStudentEntityList.size();
    ExecutorService executorService = Executors.newFixedThreadPool(nThreads);
    List<Future<Integer>> futures = new ArrayList<Future<Integer>>(nThreads);

    for (int i = 0; i < nThreads; i++) {final List<EnrollStudentEntity> EnrollStudentEntityImputList = enrollStudentEntityList.subList(size / nThreads * i, size / nThreads * (i + 1));
        final List<StudentEntity> studentEntityImportList = studentEntityList.subList(size / nThreads * i, size / nThreads * (i + 1));
        final List<AllusersEntity> allusersEntityImportList = allusersEntityList.subList(size / nThreads * i, size / nThreads * (i + 1));

       Callable<Integer> task1 = () -> {studentSave.saveStudent(EnrollStudentEntityImputList,studentEntityImportList,allusersEntityImportList);
           return 1;
        };
      futures.add(executorService.submit(task1));
    }
    executorService.shutdown();
    if (!futures.isEmpty() && futures != null) {return 10;}
    return -10;
}

代码阐明：

下面是通过利用 ExecutorService 建设了固定的线程数，而后依据线程数目进行分组，批量顺次导入。一方面能够缓解数据库的压力，另一个面线程数目多了，肯定水平会进步程序运行的工夫。

毛病就是要看服务器的配置，如果配置好的话就能够开多点线程，配置差的话就开小点。

五、小结

通过应用这个操作真是一直的进步了，我的项目应用技巧也是不错。

加油 多线程哦

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2022-03-25
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