Mybatis Plus用自定义新增，来实现真正的批量新增方式

编写自定义insert和update的SQL 批量处理方法
insert

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.TableFieldInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
import lombok.Setter;
import lombok.experimental.Accessors;
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 java.util.List;
import java.util.function.Predicate;


/**
 * @author aaa
 * @date 2023-09-27 18:27
 * @description
 */
public class InsertBatchColumn extends AbstractMethod {

    /**
     * 字段筛选条件
     */
    @Setter
    @Accessors(chain = true)
    private Predicate predicate;

    public InsertBatchColumn() {
        super("insertBatch");
    }

    public InsertBatchColumn(Predicate predicate) {
    	// 此处的名称必须与后续的RootMapper的新增方法名称一致
        super("insertBatch");
        this.predicate = predicate;
    }

    @SuppressWarnings("Duplicates")
    @Override
    public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
        KeyGenerator keyGenerator = NoKeyGenerator.INSTANCE;
        SqlMethod sqlMethod = SqlMethod.INSERT_ONE;
        List fieldList = tableInfo.getFieldList();
        String insertSqlColumn = tableInfo.getKeyInsertSqlColumn(true,false) +
                this.filterTableFieldInfo(fieldList, predicate, TableFieldInfo::getInsertSqlColumn, EMPTY);
        String columnScript = LEFT_BRACKET + insertSqlColumn.substring(0, insertSqlColumn.length() - 1) + RIGHT_BRACKET;
        String insertSqlProperty = tableInfo.getKeyInsertSqlProperty(true,ENTITY_DOT, false) +
                this.filterTableFieldInfo(fieldList, predicate, i -> i.getInsertSqlProperty(ENTITY_DOT), EMPTY);
        insertSqlProperty = LEFT_BRACKET + insertSqlProperty.substring(0, insertSqlProperty.length() - 1) + RIGHT_BRACKET;
        String valuesScript = SqlScriptUtils.convertForeach(insertSqlProperty, "list", null, ENTITY, COMMA);
        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 (tableInfo.havePK()) {
            if (tableInfo.getIdType() == IdType.AUTO) {
                /* 自增主键 */
                keyGenerator = Jdbc3KeyGenerator.INSTANCE;
                keyProperty = tableInfo.getKeyProperty();
                keyColumn = tableInfo.getKeyColumn();
            } else {
                if (null != tableInfo.getKeySequence()) {
                    keyGenerator = TableInfoHelper.genKeyGenerator(modelClass.getName(), tableInfo, builderAssistant);
                    keyProperty = tableInfo.getKeyProperty();
                    keyColumn = tableInfo.getKeyColumn();
                }
            }
        }
        String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), columnScript, valuesScript);
        SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
		// 注意第三个参数，需要与后续的RootMapper里面新增方法名称要一致，不然会报无法绑定异常
        return this.addInsertMappedStatement(mapperClass, modelClass, "insertBatch", sqlSource, keyGenerator, keyProperty, keyColumn);

    }
}

update

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


/**
 * @author aaa
 * @date 2023-09
 * @description
 */
public class UpdateBatchColumn extends AbstractMethod {

    /**
     * @param methodName 方法名
     * @since 3.5.0
     */
    public UpdateBatchColumn(String methodName) {
        super(methodName);
    }

    @SuppressWarnings("Duplicates")
    @Override
    public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
        String sql = "";
        String additional = tableInfo.isWithVersion() ? tableInfo.getVersionFieldInfo().getVersionOli("item", "item.") : "" + tableInfo.getLogicDeleteSql(true, true);
        String setSql = sqlSet(tableInfo.isWithLogicDelete(), false, tableInfo, false, "item", "item.");
        String sqlResult = String.format(sql, tableInfo.getTableName(), setSql, tableInfo.getKeyColumn(), "item." + tableInfo.getKeyProperty(), additional);
        SqlSource sqlSource = languageDriver.createSqlSource(configuration, sqlResult, modelClass);
        // 第三个参数必须和RootMapper的自定义方法名一致
        return this.addUpdateMappedStatement(mapperClass, modelClass, "updateBatch", sqlSource);


    }


}

2,创建一个 SQL 注入器 InsertBatchSqlInjector

import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.injector.DefaultSqlInjector;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import com.example.ftserver.plugin.InsertBatchColumn;
import com.example.ftserver.plugin.UpdateBatchColumn;

import java.util.List;

/**
 * @author aaa
 * @description
 */
public class CustomizedSqlInjector extends DefaultSqlInjector {


    public List getMethodList(Class mapperClass, TableInfo tableInfo) {
        List methods = super.getMethodList(mapperClass,tableInfo);
        // 自定义的insert SQL注入器
        methods.add(new InsertBatchColumn());
        // 自定义的update SQL注入器，参数需要与RootMapper的批量update名称一致
        methods.add(new UpdateBatchColumn("updateBatch")); 
        return methods;
    }


}

3,将SQL 注入器放入配置类

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @author aaa
 * @description
 */
@Configuration
@MapperScan(basePackages = "com.example.ftserver.mapper") // 不用配置.*
public class MybatisPlusConfig {

    @Bean
    public CustomizedSqlInjector sqlInjector(){
        return new CustomizedSqlInjector();
    }
    /**
     * 添加分页插件
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));//如果配置多个插件,切记分页最后添加
        return interceptor;
    }
}

4,新建一个在 config 包下创建 RootMapper 接口，让其继承自 Mybatis Plus 提供的 BaseMapper, 并定义批量插入方法

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

import java.util.Collection;

/**
 * @author aaa
 * @date 2023-09-28 16:11
 * @description
 */
public interface RootMapper extends BaseMapper {
	// 新增方法
    int insertBatch(@Param("list")Collection batchList);
    // 修改方法
    int updateBatch(@Param("list")Collection batchList);
}

5,新建 自己的Mapper，注意继承刚刚自定义的 RootMapper, 而不是Mybatis plus的 BaseMapper :

import com.test.ft.common.entity.PersonEntity;
import com.example.ftserver.plugin.RootMapper;
import org.apache.ibatis.annotations.Mapper;

/**
 * 

 *  Mapper 接口
 * 
 *
 * @author aaa
 * @since 2023-10-19 16:32:39
 */
public interface PersonMapper extends RootMapper {

}

批量修改会报错，Mybatis映射文件中的sql语句默认是不支持以" ; " 结尾，也就是不支持多条sql语句的执行。需要在连接mysql的url上加 &allowMultiQueries=true 运行批量操作才可以执行。

如果数据库设置了默认值，用批量添加汇会存null，修改如下：

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.TableFieldInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
import lombok.Setter;
import lombok.experimental.Accessors;
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 java.util.List;
import java.util.function.Predicate;


/**
 * @author aaa
 * @date 2023-09-27 18:27
 * @description
 */
public class InsertBatchColumn extends AbstractMethod {

    /**
     * 字段筛选条件
     */
    @Setter
    @Accessors(chain = true)
    private Predicate predicate;

    public InsertBatchColumn() {
        super("insertBatch");
    }

    public InsertBatchColumn(Predicate predicate) {
        // 此处的名称必须与后续的RootMapper的新增方法名称一致
        super("insertBatch");
        this.predicate = predicate;
    }

    @SuppressWarnings("Duplicates")
    @Override
    public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
        KeyGenerator keyGenerator = NoKeyGenerator.INSTANCE;
        SqlMethod sqlMethod = SqlMethod.INSERT_ONE;
        List fieldList = tableInfo.getFieldList();
        String insertSqlColumn = tableInfo.getKeyInsertSqlColumn(true, false) +
                this.filterTableFieldInfo(fieldList, predicate, TableFieldInfo::getInsertSqlColumn, EMPTY);
        String columnScript = LEFT_BRACKET + insertSqlColumn.substring(0, insertSqlColumn.length() - 1) + RIGHT_BRACKET;
/*        String insertSqlProperty = tableInfo.getKeyInsertSqlProperty(true, ENTITY_DOT, false) +
                this.filterTableFieldInfo(fieldList, predicate, i -> i.getInsertSqlProperty(ENTITY_DOT), EMPTY);*/
        String insertSqlProperty = tableInfo.getKeyInsertSqlProperty(true, ENTITY_DOT, false) +
                this.filterTableFieldInfo(fieldList, predicate, i -> getInsertSqlProperty(i, ENTITY_DOT), EMPTY);
        insertSqlProperty = LEFT_BRACKET + insertSqlProperty.substring(0, insertSqlProperty.length() - 1) + RIGHT_BRACKET;
        String valuesScript = SqlScriptUtils.convertForeach(insertSqlProperty, "list", null, ENTITY, COMMA);
        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 (tableInfo.havePK()) {
            if (tableInfo.getIdType() == IdType.AUTO) {
                /* 自增主键 */
                keyGenerator = Jdbc3KeyGenerator.INSTANCE;
                keyProperty = tableInfo.getKeyProperty();
                keyColumn = tableInfo.getKeyColumn();
            } else {
                if (null != tableInfo.getKeySequence()) {
                    keyGenerator = TableInfoHelper.genKeyGenerator(modelClass.getName(), tableInfo, builderAssistant);
                    keyProperty = tableInfo.getKeyProperty();
                    keyColumn = tableInfo.getKeyColumn();
                }
            }
        }
        String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), columnScript, valuesScript);
        SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
        // 注意第三个参数，需要与后续的RootMapper里面新增方法名称要一致，不然会报无法绑定异常
        return this.addInsertMappedStatement(mapperClass, modelClass, "insertBatch", sqlSource, keyGenerator, keyProperty, keyColumn);

    }

    private String getInsertSqlProperty(TableFieldInfo tableFieldInfo, final String prefix) {
        String newPrefix = prefix == null ? "" : prefix;
        String elPart = SqlScriptUtils.safeParam(newPrefix + tableFieldInfo.getEl());
        //属性为空时使用默认值
        String result = SqlScriptUtils.convertIf(elPart,
                String.format("%s != null", newPrefix + tableFieldInfo.getEl()), false)
                + SqlScriptUtils.convertIf("default",
                String.format("%s == null", newPrefix + tableFieldInfo.getEl()), false);
        return result + ",";
    }

}

总结
以上就是MyBatis plus对MySQL实现批量新增，批量修改的内容，才疏学浅，如有错误，希望多多的指正。需要注意的是：**该方法只对MySQL测试过，其他的数据库支持度不一致，不一定适用