mybatis-plus批量更新太慢该如何解决详解

最近使用mybatis-plus的 saveOrUpdateBath 和saveBath接口执行特别慢，数据量大时往往需要十几分钟，打开日志查看原来批量操作也是循环单条数据插入的，那有没有批量更新的办法呢？？

mybatis-plus 提供了一个自定义方法sql注入器DefaultSqlInjector我们可以通过继DefaultSqlInjector来加入自定义的方法达到批量插入的效果。

import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.injector.DefaultSqlInjector;
import org.springframework.stereotype.Component;

import java.util.List;

/**
 * @Description: 自定义方法SQL注入器
 * @Title: CustomizedSqlInjector
 * @Package com.highgo.edu.common.batchOperation
 * @Author:
 * @Copyright
 * @CreateTime: 2022/11/3 16:21
 */
@Component
public class CustomizedSqlInjector  extends DefaultSqlInjector {
    /**
     * 如果只需增加方法，保留mybatis plus自带方法，
     * 可以先获取super.getMethodList()，再添加add
     */
    @Override
    public List<AbstractMethod> getMethodList(Class<?> mapperClass) {
        List<AbstractMethod> methodList = super.getMethodList(mapperClass);
        methodList.add(new InsertBatchMethod());
       // methodList.add(new UpdateBatchMethod());
        methodList.add(new MysqlInsertOrUpdateBath());
        methodList.add(new PGInsertOrUpdateBath());
        return methodList;
    }

}

同时我们需要继承BaseMapper<T> 定义

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Param;

import java.util.List;
/**
 * @description:自定义接口覆盖BaseMapper，解决mybatis-plus 批量操作慢的问题
 * @author:
 * @date: 2022/11/3 15:14
 * @param: null
 * @return:
 **/
public interface RootMapper<T> extends BaseMapper<T> {
    /**
     * @description:批量插入
     * @author:
     * @date: 2022/11/3 15:13
     * @param: [list]
     * @return: int
     **/
    int insertBatch(@Param("list") List<T> list);
    /**
     * @description:批量插入更新
     * @author:
     * @date: 2022/11/3 15:14
     * @param: [list]
     * @return: int
     **/
    int mysqlInsertOrUpdateBatch(@Param("list") List<T> list);

    int pgInsertOrUpdateBatch(@Param("list") List<T> list);
}

在需要使用批量更新插入的mapper上使用自定义的RootMapper

如下图

import com.XX.edu.common.batchOperation.RootMapper;
import com.XX.edu.exam.model.TScore;
import org.springframework.stereotype.Repository;

/**
 * @Entity com.XX.edu.exam.model.TScore
 */
@Repository
public interface TScoreMapper extends RootMapper<TScore> {

}

下面我们来定义批量插入的方法：

package com.XX.edu.common.batchOperation;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.core.enums.SqlMethod;
import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
import org.apache.commons.lang3.StringUtils;
import org.apache.ibatis.executor.keygen.Jdbc3KeyGenerator;
import org.apache.ibatis.executor.keygen.KeyGenerator;
import org.apache.ibatis.executor.keygen.NoKeyGenerator;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @Description: 批量插入的方法
 * @Title: InsertBatchMethod
 * @Package com.XX.edu.common.batchOperation
 * @Author:
 * @CreateTime: 2022/11/3 15:16
 */
public class InsertBatchMethod extends AbstractMethod {
    Logger logger = LoggerFactory.getLogger(getClass());

    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
        final String sql = "<script>insert into %s %s values %s</script>";
        final String fieldSql = prepareFieldSql(tableInfo);
        final String valueSql = prepareValuesSql(tableInfo);
        final String sqlResult = String.format(sql, tableInfo.getTableName(), fieldSql, valueSql);
        logger.debug("sqlResult----->{}", sqlResult);
        SqlSource sqlSource = languageDriver.createSqlSource(configuration, sqlResult, modelClass);
        KeyGenerator keyGenerator = new NoKeyGenerator();
        SqlMethod sqlMethod = SqlMethod.INSERT_ONE;
        String keyProperty = null;
        String keyColumn = null;
        // 表包含主键处理逻辑,如果不包含主键当普通字段处理
        if (StringUtils.isNotEmpty(tableInfo.getKeyProperty())) {
            if (tableInfo.getIdType() == IdType.AUTO) {
                /* 自增主键 */
                keyGenerator = new Jdbc3KeyGenerator();
                keyProperty = tableInfo.getKeyProperty();
                keyColumn = tableInfo.getKeyColumn();
            } else {
                if (null != tableInfo.getKeySequence()) {
                    keyGenerator = TableInfoHelper.genKeyGenerator(sqlMethod.getMethod(),tableInfo, builderAssistant);
                    keyProperty = tableInfo.getKeyProperty();
                    keyColumn = tableInfo.getKeyColumn();
                }
            }
        }
        // 第三个参数必须和RootMapper的自定义方法名一致
        return this.addInsertMappedStatement(mapperClass, modelClass, "insertBatch", sqlSource, keyGenerator, keyProperty, keyColumn);
    }

    /**
     * @description: 拼接字段值
     * @author:
     * @date: 2022/11/3 15:20
     * @param: [tableInfo]
     * @return: java.lang.String
     **/
    private String prepareValuesSql(TableInfo tableInfo) {
        final StringBuilder valueSql = new StringBuilder();
        valueSql.append("<foreach collection=\"list\" item=\"item\" index=\"index\" open=\"(\" separator=\"),(\" close=\")\">");
        //valueSql.append("#{item.").append(tableInfo.getKeyProperty()).append("},");
        tableInfo.getFieldList().forEach(x -> valueSql.append("#{item.").append(x.getProperty()).append("},"));
        valueSql.delete(valueSql.length() - 1, valueSql.length());
        valueSql.append("</foreach>");
        return valueSql.toString();
    }

    /**
     * @description:拼接字段
     * @author:
     * @date: 2022/11/3 15:20
     * @param: [tableInfo]
     * @return: java.lang.String
     **/
    private String prepareFieldSql(TableInfo tableInfo) {
        StringBuilder fieldSql = new StringBuilder();
        //fieldSql.append(tableInfo.getKeyColumn()).append(",");
        tableInfo.getFieldList().forEach(x -> {
            fieldSql.append(x.getColumn()).append(",");
        });
        fieldSql.delete(fieldSql.length() - 1, fieldSql.length());
        fieldSql.insert(0, "(");
        fieldSql.append(")");
        return fieldSql.toString();
    }
}

继续定义批量插入更新的抽象方法

package com.XX.edu.common.batchOperation;

import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import org.apache.ibatis.executor.keygen.NoKeyGenerator;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlSource;

/**
 * @Description: 批量插入更新
 * @Title: InsertOrUpdateBath
 * @Package com.XX.edu.common.batchOperation
 * @Author:
 * @Copyright
 * @CreateTime: 2022/11/3 15:23
 */
public abstract class InsertOrUpdateBathAbstract extends AbstractMethod {
    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
        final  SqlSource sqlSource = prepareSqlSource(tableInfo, modelClass);
        // 第三个参数必须和RootMapper的自定义方法名一致
        return this.addInsertMappedStatement(mapperClass, modelClass, prepareInsertOrUpdateBathName(), sqlSource, new NoKeyGenerator(), null, null);

    }

    protected abstract SqlSource prepareSqlSource(TableInfo tableInfo, Class<?> modelClass);

    protected abstract String prepareInsertOrUpdateBathName();

}

继承上面的抽象类----mysql版本（本版本未测试 根据自己需求修改）

package com.XX.edu.common.batchOperation;

import com.baomidou.mybatisplus.core.metadata.TableInfo;
import org.apache.ibatis.mapping.SqlSource;
import org.springframework.util.StringUtils;

/**
 * @Description: 批量插入更新
 * @Title: InsertOrUpdateBath
 * @Package com.XX.edu.common.batchOperation
 * @Author:
 * @Copyright
 * @CreateTime: 2022/11/3 15:23
 */
public class MysqlInsertOrUpdateBath extends InsertOrUpdateBathAbstract {

    @Override
    protected SqlSource prepareSqlSource(TableInfo tableInfo, Class<?> modelClass) {
        final String sql = "<script>insert into %s %s values %s ON DUPLICATE KEY UPDATE %s</script>";
        final String tableName = tableInfo.getTableName();
        final String filedSql = prepareFieldSql(tableInfo);
        final String modelValuesSql = prepareModelValuesSql(tableInfo);
        final String duplicateKeySql = prepareDuplicateKeySql(tableInfo);
        final String sqlResult = String.format(sql, tableName, filedSql, modelValuesSql, filedSql, duplicateKeySql);
        //String.format(sql, tableName, filedSql, modelValuesSql, duplicateKeySql);
        //System.out.println("savaorupdatesqlsql="+sqlResult);
        return languageDriver.createSqlSource(configuration, sqlResult, modelClass);
    }

    @Override
    protected String prepareInsertOrUpdateBathName() {
        return "mysqlInsertOrUpdateBath";
    }

    String prepareDuplicateKeySql(TableInfo tableInfo) {
        final StringBuilder duplicateKeySql = new StringBuilder();
        if (!StringUtils.isEmpty(tableInfo.getKeyColumn())) {
            duplicateKeySql.append(tableInfo.getKeyColumn()).append("=values(").append(tableInfo.getKeyColumn()).append("),");
        }

        tableInfo.getFieldList().forEach(x -> {
            duplicateKeySql.append(x.getColumn())
                    .append("=values(")
                    .append(x.getColumn())
                    .append("),");
        });
        duplicateKeySql.delete(duplicateKeySql.length() - 1, duplicateKeySql.length());
        return duplicateKeySql.toString();
    }

    String prepareModelValuesSql(TableInfo tableInfo) {
        final StringBuilder valueSql = new StringBuilder();
        valueSql.append("<foreach collection=\"list\" item=\"item\" index=\"index\" open=\"(\" separator=\"),(\" close=\")\">");
        if (!StringUtils.isEmpty(tableInfo.getKeyProperty())) {
            valueSql.append("#{item.").append(tableInfo.getKeyProperty()).append("},");
        }
        tableInfo.getFieldList().forEach(x -> valueSql.append("#{item.").append(x.getProperty()).append("},"));
        valueSql.delete(valueSql.length() - 1, valueSql.length());
        valueSql.append("</foreach>");
        return valueSql.toString();
    }

    /**
     * @description:准备属性名
     * @author:
     * @date: 2022/11/3 15:25
     * @param: [tableInfo]
     * @return: java.lang.String
     **/
    String prepareFieldSql(TableInfo tableInfo) {
        StringBuilder fieldSql = new StringBuilder();
        fieldSql.append(tableInfo.getKeyColumn()).append(",");
        tableInfo.getFieldList().forEach(x -> {
            fieldSql.append(x.getColumn()).append(",");
        });
        fieldSql.delete(fieldSql.length() - 1, fieldSql.length());
        fieldSql.insert(0, "(");
        fieldSql.append(")");
        return fieldSql.toString();
    }
}

继承上面的抽象类----postgresql版本（已测试完成，其中id使用序列自增）

package com.XX.edu.common.batchOperation;

import com.baomidou.mybatisplus.core.metadata.TableInfo;
import org.apache.ibatis.mapping.SqlSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;

/**
 * @Description: 批量插入更新
 * @Title: InsertOrUpdateBath
 * @Package com.XX.edu.common.batchOperation
 * @Author:
 * @Copyright
 * @CreateTime: 2022/11/3 15:23
 */
public class PGInsertOrUpdateBath extends InsertOrUpdateBathAbstract {
    Logger logger = LoggerFactory.getLogger(getClass());
    @Override
    protected SqlSource prepareSqlSource(TableInfo tableInfo, Class<?> modelClass) {
        final String sql = "<script>insert into %s %s values %s on conflict (id)  do update set %s </script>";
        final String tableName = tableInfo.getTableName();
        final String filedSql = prepareFieldSql(tableInfo);
        final String modelValuesSql = prepareModelValuesSql(tableInfo);
        final String duplicateKeySql = prepareDuplicateKeySql(tableInfo);
        final String sqlResult = String.format(sql, tableName, filedSql, modelValuesSql, duplicateKeySql);
        logger.info("sql=={}",sqlResult);
        return languageDriver.createSqlSource(configuration, sqlResult, modelClass);
    }

    @Override
    protected String prepareInsertOrUpdateBathName() {
        return "pgInsertOrUpdateBatch";
    }

    private String prepareDuplicateKeySql(TableInfo tableInfo) {
        final StringBuilder duplicateKeySql = new StringBuilder();
        if (!StringUtils.isEmpty(tableInfo.getKeyColumn())) {
            duplicateKeySql.append(tableInfo.getKeyColumn()).append("=excluded.").append(tableInfo.getKeyColumn()).append(",");
        }

        tableInfo.getFieldList().forEach(x -> {
            duplicateKeySql.append(x.getColumn())
                    .append("=excluded.")
                    .append(x.getColumn())
                    .append(",");
        });
        duplicateKeySql.delete(duplicateKeySql.length() - 1, duplicateKeySql.length());
        return duplicateKeySql.toString();
    }

    private String prepareModelValuesSql(TableInfo tableInfo) {
        final StringBuilder valueSql = new StringBuilder();
        valueSql.append("<foreach collection=\"list\" item=\"item\" index=\"index\" open=\"(\" separator=\"),(\" close=\")\">");
        if (!StringUtils.isEmpty(tableInfo.getKeyProperty())) {
            valueSql.append("#{item.").append(tableInfo.getKeyProperty()).append("},");
        }
        tableInfo.getFieldList().forEach(x -> valueSql.append("#{item.").append(x.getProperty()).append("},"));
        valueSql.delete(valueSql.length() - 1, valueSql.length());
        valueSql.append("</foreach>");
        return valueSql.toString();
    }

    /**
     * @description:准备属性名
     * @author:
     * @date: 2022/11/3 15:25
     * @param: [tableInfo]
     * @return: java.lang.String
     **/
    private String prepareFieldSql(TableInfo tableInfo) {
        StringBuilder fieldSql = new StringBuilder();
        if (!StringUtils.isEmpty(tableInfo.getKeyProperty())) {
            fieldSql.append(tableInfo.getKeyColumn()).append(",");
        }

        tableInfo.getFieldList().forEach(x -> {
            fieldSql.append(x.getColumn()).append(",");
        });
        fieldSql.delete(fieldSql.length() - 1, fieldSql.length());
        fieldSql.insert(0, "(");
        fieldSql.append(")");
        return fieldSql.toString();
    }
}

到此定义结束，下面开始使用

@Service
public class TNewExerciseServiceImpl extends ServiceImpl<TNewExerciseMapper, TNewExercise>
        implements TNewExerciseService {
    Logger logger = LoggerFactory.getLogger(getClass());
//引入mapper
@Autowired
TScoreMapper scoreMapper;
//这样就可以批量新增更新操作了
public void test(List<TScore> collect){
 scoreMapper.pgInsertOrUpdateBatch(collect);
}

}

但是如果collect数据量太大会出现异常
“Tried to send an out-of-range integer as a 2-byte value: 87923”
是因为pg对于sql语句的参数数量是有限制的，最大为32767。

看pg源码

public void sendInteger2(int val) throws IOException {
        if (val >= -32768 && val <= 32767) {
            this.int2Buf[0] = (byte)(val >>> 8);
            this.int2Buf[1] = (byte)val;
            this.pgOutput.write(this.int2Buf);
        } else {
            throw new IOException("Tried to send an out-of-range integer as a 2-byte value: " + val);
        }
    }

从源代码中可以看到pgsql使用2个字节的integer，故其取值范围为[-32768, 32767]。

这意味着sql语句的参数数量，即行数*列数之积必须小于等于32767.

比如，总共有17个字段，因为最大是32767，这样最多允许32767/ 17 大约是1 927个，所以要分批操作，或有能力的童鞋可以自己修改pg的驱动呦

分批插入代码如下：

    /**
     * @description:
     * @author:
     * @date: 2022/11/4 14:57
     * @param: [list, fieldCount:列数]
     * @return: void
     **/
    public void detachSaveOrUpdate_score(List<TScore> list, int fieldCount) {
        int numberBatch = 32767; //每一次插入的最大数
        //每一次插入的最大行数 ， 向下取整
        int v = ((Double) Math.floor(numberBatch / (fieldCount * 1.0))).intValue();
        double number = list.size() * 1.0 / v;
        int n = ((Double) Math.ceil(number)).intValue(); //向上取整
        for (int i = 0; i < n; i++) {
            int end = v * (i + 1);
            if (end > list.size()) {
                end = list.size(); //如果end不能超过最大索引值
            }
            scoreMapper.pgInsertOrUpdateBatch(list.subList(v * i, end)); //插入数据库
            logger.info("更新一次~~~{}-{}", v * i, end);
        }
    }

完成收工~~~

总结

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