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

一、前言

前兩天做了一個導入的功能，導入開始的時候非常慢，導入2w條數(shù)據(jù)要1分多鐘，后來一點一點的優(yōu)化，從直接把list懟進Mysql中，到分配把list導入Mysql中，到多線程把list導入Mysql中。

時間是一點一點的變少了。非常的爽，最后變成了10s以內(nèi)。

下面就展示一下過程。

二、直接把list懟進Mysql

@Transactional(rollbackFor?=?Exception.class)
public?int?addFreshStudentsNew2(List?list,?String?schoolNo)?{
????if?(list?==?null?||?list.isEmpty())?{
????????return?0;
????}
????List?studentEntityList?=?new?LinkedList<>();
????List?enrollStudentEntityList?=?new?LinkedList<>();
????List?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());??//密碼設(shè)置為考生號
????????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;
}

推薦一個 Spring Boot 基礎(chǔ)教程及實戰(zhàn)示例：

https://github.com/javastacks/spring-boot-best-practice

Mapper.xml

"insertAll"?parameterType="com.dmsdbj.itoo.basicInfo.entity.EnrollStudentEntity">
????insert?into?tb_enroll_student
????"("?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????????????????
????values
????"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()????????
????)???
????????????????????
?

代碼說明：

底層的mapper是通過逆向工程來生成的，批量插入如下，是拼接成類似：insert into tb_enroll_student（）values （），（）…….（）;

關(guān)注Java項目精選，推送更多 Java 干貨！

這樣的缺點是，數(shù)據(jù)庫一般有一個默認的設(shè)置，就是每次sql操作的數(shù)據(jù)不能超過4M。這樣插入，數(shù)據(jù)多的時候，數(shù)據(jù)庫會報錯Packet for query is too large (6071393 > 4194304). You can change this value on the server by setting the max_allowed_packet' variable.，雖然我們可以通過

類似修改 my.ini 加上 max_allowed_packet =67108864，67108864=64M，默認大小4194304 也就是4M

修改完成之后要重啟mysql服務(wù)，如果通過命令行修改就不用重啟mysql服務(wù)。

完成本次操作，但是我們不能保證項目單次最大的大小是多少，這樣是有弊端的。所以可以考慮進行分組導入。

三、分組把list導入Mysql中

同樣適用mybatis批量插入，區(qū)別是對每次的導入進行分組計算，然后分多次進行導入：

@Transactional(rollbackFor?=?Exception.class)
public?int?addFreshStudentsNew2(List?list,?String?schoolNo)?{
????if?(list?==?null?||?list.isEmpty())?{
????????return?0;
????}
????List?studentEntityList?=?new?LinkedList<>();
????List?enrollStudentEntityList?=?new?LinkedList<>();
????List?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());??//密碼設(shè)置為考生號
????????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;
}

代碼說明：

這樣操作，可以避免上面的錯誤，但是分多次插入，無形中就增加了操作實踐，很容易超時。所以這種方法還是不值得提倡的。

再次改進，使用多線程分批導入。

四、多線程分批導入Mysql

依然使用mybatis的批量導入，不同的是，根據(jù)線程數(shù)目進行分組，然后再建立多線程池，進行導入。

@Transactional(rollbackFor?=?Exception.class)
public?int?addFreshStudentsNew(List?list,?String?schoolNo)?{
????if?(list?==?null?||?list.isEmpty())?{
????????return?0;
????}
????List?studentEntityList?=?new?LinkedList<>();
????List?enrollStudentEntityList?=?new?LinkedList<>();
????List?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());??//密碼設(shè)置為考生號
????????allusersEntityList.add(allusersEntity);
????});


????int?nThreads?=?50;

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

????for?(int?i?=?0;?i?????????final?List?EnrollStudentEntityImputList?=?enrollStudentEntityList.subList(size?/?nThreads?*?i,?size?/?nThreads?*?(i?+?1));
????????final?List?studentEntityImportList?=?studentEntityList.subList(size?/?nThreads?*?i,?size?/?nThreads?*?(i?+?1));
????????final?List?allusersEntityImportList?=?allusersEntityList.subList(size?/?nThreads?*?i,?size?/?nThreads?*?(i?+?1));

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

代碼說明：

上面是通過應(yīng)用ExecutorService 建立了固定的線程數(shù)，然后根據(jù)線程數(shù)目進行分組，批量依次導入。一方面可以緩解數(shù)據(jù)庫的壓力，另一個面線程數(shù)目多了，一定程度會提高程序運行的時間。

缺點就是要看服務(wù)器的配置，如果配置好的話就可以開多點線程，配置差的話就開小點。

五、小結(jié)

通過使用這個操作真是不斷的提高了，項目使用技巧也是不錯。

加油~~ 多線程哦~~


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給你 2 萬條數(shù)據(jù)，怎么快速導入到 MySQL？寫得太好了！

一、前言

二、直接把list懟進Mysql

三、分組把list導入Mysql中

四、多線程分批導入Mysql

五、小結(jié)

給你 2 萬條數(shù)據(jù)，怎么快速導入到 MySQL？寫得太好了！

一、前言

二、直接把list懟進Mysql

三、分組把list導入Mysql中

四、多線程分批導入Mysql

五、小結(jié)