MyBatis Plus基于自定义BaseMapper来添加批量插入、批量更新方法

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已于 2022-06-17 09:51:16 修改

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于 2020-10-15 18:24:31 首次发布

本文链接：https://blog.youkuaiyun.com/LSL1618/article/details/109102424

本文档展示了如何在MybatisPlus中自定义`BaseMapper`接口，添加批量插入和批量更新的方法，并通过自定义SQL注入器使这些方法生效。首先，定义了`RootMapper`接口，扩展了`BaseMapper`并添加了两个自定义方法。接着，实现了`InsertBatchMethod`和`UpdateBatchMethod`，分别处理批量插入和批量更新的逻辑。然后，创建了一个`CustomizedSqlInjector`类，用于注入自定义方法。最后，在配置文件中配置这个自定义SQL注入器，使其在项目中生效。

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1. 自定义BaseMapper


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

import java.util.List;

/**
 * 根Mapper，给表Mapper继承用的，可以自定义通用方法
 * {@link com.baomidou.mybatisplus.core.mapper.BaseMapper}
 * {@link com.baomidou.mybatisplus.extension.service.IService}
 * {@link com.baomidou.mybatisplus.extension.service.impl.ServiceImpl}
 */
public interface RootMapper<T> extends BaseMapper<T> {

    /**
     * 自定义批量插入
     * 如果要自动填充，@Param(xx) xx参数名必须是 list/collection/array 3个的其中之一
     */
    int insertBatch(@Param("list") List<T> list);

    /**
     * 自定义批量更新，条件为主键
     * 如果要自动填充，@Param(xx) xx参数名必须是 list/collection/array 3个的其中之一
     */
    int updateBatch(@Param("list") List<T> list);

}

2. 批量插入方法实现


import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.executor.keygen.NoKeyGenerator;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlSource;

/**
 * 批量插入方法实现
 */
@Slf4j
public class InsertBatchMethod extends AbstractMethod {
    /**
     * insert into user(id, name, age) values (1, "a", 17), (2, "b", 18);
     <script>
     insert into user(id, name, age) values
     <foreach collection="list" item="item" index="index" open="(" separator="),(" close=")">
     #{item.id}, #{item.name}, #{item.age}
     </foreach>
     </script>
     */
    @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);
        log.debug("sqlResult----->{}", sqlResult);
        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.addInsertMappedStatement(mapperClass, modelClass, "insertBatch", sqlSource, new NoKeyGenerator(), null, null);
    }

    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();
    }

    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();
    }
}

3. 批量更新方法实现


import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlSource;

/**
 * 批量更新方法实现，条件为主键，选择性更新
 */
@Slf4j
public class UpdateBatchMethod extends AbstractMethod {
    /**
     * update user set name = "a", age = 17 where id = 1;
     * update user set name = "b", age = 18 where id = 2;
     <script>
     <foreach collection="list" item="item" separator=";">
     update user
     <set>
     <if test="item.name != null and item.name != ''">
     name = #{item.name,jdbcType=VARCHAR},
     </if>
     <if test="item.age != null">
     age = #{item.age,jdbcType=INTEGER},
     </if>
     </set>
     where id = #{item.id,jdbcType=INTEGER}
     </foreach>
     </script>
     */
    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
        String sql = "<script>\n<foreach collection=\"list\" item=\"item\" separator=\";\">\nupdate %s %s where %s=#{%s} %s\n</foreach>\n</script>";
        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);
        log.debug("sqlResult----->{}", sqlResult);
        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);
    }

}

4. 自定义方法SQL注入器


import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.injector.DefaultSqlInjector;

import java.util.List;

/**
 * 自定义方法SQL注入器
 */
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());
        return methodList;
    }
}

5. 配置SQL注入器使其生效


import cn.config.CustomizedSqlInjector;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@MapperScan(basePackages = "cn.mapper")
@Configuration
public class MybatisPlusConfig {

    @Bean
    public CustomizedSqlInjector customizedSqlInjector() {
        return new CustomizedSqlInjector();
    }

}

备注：以下是当时所用的 Mybatis Plus 引用依赖版本，新版本可能需要结合Mybatis Plus最新官方文档进行调整。

<dependency>
	<groupId>com.baomidou</groupId>
	<artifactId>mybatis-plus-boot-starter</artifactId>
	<version>3.4.0</version>
</dependency>