Mybatis苞米豆（baomidou）使用说明书

2年前 (2022) 程序员胖胖胖虎阿

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一、背景

二、配置

1、pom文件配置

2、yml文件配置

3、SQL准备

三、具体代码（增删改查）

四、Wrapper中的QueryWrapper常用ge,gt,lt,le等具体含义

五、参考文献

一、背景

1.1 MyBatis-Plus 是由一个叫苞米豆的一个组织来开发的，组织负责人叫青苗，目前组织中大概有31人。MyBatis-Plus（ https://mybatis.plus/）简称 MP是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。MyBatis-Plus 可以不需要写SQL语句就能快速完成单表的操作，MyBatis-Plus的愿景就是成为 MyBatis 最好的搭档，就像魂斗罗中的 1P、2P，基友搭配，效率翻倍。

1.2 代码地址：

GitHub（https://github.com/baomidou/mybatis-plus）

码云（https://gitee.com/organizations/baomidou/）

本文主要以贴代码为主，实战为王。

二、配置

1、pom文件配置

 <properties>
    <java.version>1.8</java.version>
    <mybatisplus.version>3.3.1</mybatisplus.version>
 </properties>
<!--mybatis-plus-->
 <dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>${mybatisplus.version}</version>
 </dependency>
<!-- https://mvnrepository.com/artifact/com.baomidou/mybatis-plus-generator -->
 <dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>${mybatisplus.version}</version>
 </dependency>

2、yml文件配置

#mybatis配置
mybatis-plus:
  # 映射文件的位置
  mapper-locations: classpath:mapper/*.xml
  global-config:
    #数据库相关配置
    db-config:
      #主键类型  AUTO:"数据库ID自增", INPUT:"用户输入ID", ID_WORKER:"全局唯一ID (数字类型唯一ID)", UUID:"全局唯一ID UUID";
      id-type: AUTO
      #字段策略 IGNORED:"忽略判断",NOT_NULL:"非 NULL 判断"),NOT_EMPTY:"非空判断"
      field-strategy: NOT_NULL
      #驼峰下划线转换
      column-underline: true
      logic-delete-value: -1
      logic-not-delete-value: 0
    banner: false
  #原生配置
  configuration:
    map-underscore-to-camel-case: true
    cache-enabled: false
    call-setters-on-nulls: true
    jdbc-type-for-null: 'null'
  # 配置包别名
  type-aliases-package:  com.snowriver.it.springdemo.entity

3、SQL准备

CREATE TABLE `t_snow_operate_log` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT 'ID',
  `batch_no` varchar(32) DEFAULT NULL COMMENT '批次号',
  `operator` varchar(255) NOT NULL DEFAULT '' COMMENT '操作人',
  `operate_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '操作时间',
  `operate_type` tinyint(4) NOT NULL DEFAULT '-1' COMMENT '操作类型 1-导入 2-修改',
  `operate_detail` varchar(255) NOT NULL DEFAULT '' COMMENT '操作明细(导入-附件名称  修改-报单id)',
  `attachment_url` varchar(255) NOT NULL DEFAULT '' COMMENT '附件地址(操作类型为修改 该字段为空)',
  `upload_status` tinyint(4) NOT NULL DEFAULT '-1' COMMENT '上传状态 0-上传失败 1-上传成功 2-处理中',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=2245 DEFAULT CHARSET=utf8 ROW_FORMAT=COMPACT COMMENT='操作日志记录表';

三、具体代码（增删改查）

controller类：

@Slf4j
@RestController
@RequestMapping("/operate")
public class OperateLogController {

    @Resource
    private ISnowOperateLogService operateLogService;

    @PostMapping("/insert")
    public Result insert(@RequestBody OperateRecordReq request) {
        SnowOperateLog operateLog = new SnowOperateLog();
        operateLog.setOperator(request.getOperator());
        operateLog.setOperateTime(request.getOperateTimeStart());
        operateLog.setOperateType(Integer.valueOf(request.getOperateType()));
        operateLogService.save(operateLog);
        return Result.success();
    }

    @PostMapping("/insert-batch")
    public Result insertBatch(@RequestBody OperateRecordReq request) {
        LocalDateTime dateTime = LocalDateTime.now();
        List<SnowOperateLog> list = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            SnowOperateLog operateLog = new SnowOperateLog();
            operateLog.setBatchNo(String.valueOf(System.currentTimeMillis()));
            operateLog.setOperator("liudehua" + i);
            operateLog.setOperateType(1);
            operateLog.setOperateTime(dateTime);
            list.add(operateLog);
        }
        operateLogService.saveBatch(list);
        return Result.success();
    }

    @GetMapping("/delete")
    public Result<List<SnowOperateLog>> deleteById(@RequestParam(value = "id") String id) {
        operateLogService.deleteById(id);
        return Result.success();
    }

    @PostMapping("/update-by-name")
    public Result updateByOperator(@RequestBody OperateRecordReq request) {
        operateLogService.updateByOperator(request.getOperator());
        return Result.success();
    }

    @PostMapping("/queryList")
    public Result<PageDto<SnowOperateLog>> queryList(@RequestBody OperateRecordReq request) {
        return operateLogService.queryList(request);
    }

    @PostMapping("/query-by-name")
    public Result<List<SnowOperateLog>> selectAllByOperator(@RequestBody OperateRecordReq request) {
        List<SnowOperateLog> snowOperateLogs = operateLogService.selectAllByOperator(request.getOperator());
        return Result.success(snowOperateLogs);
    }
}

服务类：

public interface ISnowOperateLogService extends IService<SnowOperateLog> {

    Result<PageDto<SnowOperateLog>> queryList(OperateRecordReq request);

    List<SnowOperateLog> selectAllByOperator(String operator);

    void updateByOperator(String operator);

    void deleteById(String id);
}

实现类：

@Slf4j
@Service
public class SnowOperateLogServiceImpl extends ServiceImpl<SnowOperateLogMapper, SnowOperateLog> implements
        ISnowOperateLogService {

    @Resource
    private SnowOperateLogMapper operateLogMapper;

    // 注意：不配置MybatisPlusConfig分页不生效  TokenKind
    @Override
    public Result<PageDto<SnowOperateLog>> queryList(OperateRecordReq request) {
        LambdaQueryWrapper<SnowOperateLog> wrapper = Wrappers.lambdaQuery(SnowOperateLog.class);
        IPage<SnowOperateLog> page = new Page<>(request.getPageNum(),request.getPageSize());
        wrapper
                .eq(SnowOperateLog::getOperator,request.getOperator())
                .eq(SnowOperateLog::getOperateType,request.getOperateType())
                .ge(SnowOperateLog::getOperateTime,request.getOperateTimeStart())
                .le(SnowOperateLog::getOperateTime,request.getOperateTimeEnd())
                .orderByDesc(SnowOperateLog::getId);
        IPage<SnowOperateLog> logIPage = operateLogMapper.selectPage(page,wrapper);
        PageDto<SnowOperateLog> result = new PageDto<>(logIPage.getTotal(), logIPage.getPages()
                , logIPage.getCurrent(), logIPage.getSize()
                , logIPage.getRecords());
        return Result.success(result);
    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public List<SnowOperateLog> selectAllByOperator(String operator) {
//        // 自定义方法和SQL实现功能
//        List<SnowOperateLog> snowOperateLogs = operateLogMapper.selectAllByOperator(operator);
        LambdaQueryWrapper<SnowOperateLog> queryWrapper = Wrappers.lambdaQuery(SnowOperateLog.class)
                .eq(SnowOperateLog::getOperator, operator);
        List<SnowOperateLog> snowOperateLogs = operateLogMapper.selectList(queryWrapper);
        // 批量打印日志
        snowOperateLogs.forEach(System.out::println);
        return snowOperateLogs;
    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public void updateByOperator(String operator) {
        LambdaUpdateWrapper<SnowOperateLog> wrapper = Wrappers.lambdaUpdate(SnowOperateLog.class)
                .eq(SnowOperateLog::getOperator, "张三")
                .set(SnowOperateLog::getOperator, "张三疯======");
        super.update(wrapper);
    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public void deleteById(String id) {
        LambdaQueryWrapper<SnowOperateLog> wrapper = Wrappers.lambdaQuery(SnowOperateLog.class)
                .eq(SnowOperateLog::getId, id);
        super.remove(wrapper);
    }
}

mapper类

@Mapper
public interface SnowOperateLogMapper extends BaseMapper<SnowOperateLog> {

    List<SnowOperateLog> selectAllByOperator(@Param("operator") String operator);

}

mapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.snowriver.it.springdemo.mapper.SnowOperateLogMapper">

    <!-- 通用查询映射结果 -->
    <resultMap id="BaseResultMap" type="com.snowriver.it.springdemo.entity.SnowOperateLog">
        <id column="id" property="id" />
        <result column="batch_no" property="batchNo" />
        <result column="operator" property="operator" />
        <result column="operate_time" property="operateTime" />
        <result column="operate_type" property="operateType" />
        <result column="operate_detail" property="operateDetail" />
        <result column="attachment_url" property="attachmentUrl" />
        <result column="upload_status" property="uploadStatus" />
    </resultMap>

    <!-- 通用查询结果列 -->
    <sql id="Base_Column_List">
        id, batch_no, operator, operate_time, operate_type, operate_detail, attachment_url, upload_status
    </sql>

    <select id="selectAllByOperator" resultMap="BaseResultMap">
        select
        <include refid="Base_Column_List"/>
        from t_snow_operate_log
        where operator = #{operator, jdbcType=VARCHAR}
    </select>

</mapper>

配置类：MybatisPlusConfig

备注：如果没有该类，分页查询不生效

@Configuration
public class MybatisPlusConfig {
    @Bean
    public PaginationInterceptor paginationInterceptor(){
        return new PaginationInterceptor();
    }
}

实体类

@Data
@EqualsAndHashCode(callSuper = false)
@Accessors(chain = true)
@TableName("t_snow_operate_log")
public class SnowOperateLog implements Serializable {

    private static final long serialVersionUID = 1L;

    /**
     * ID
     */
    @TableId(value = "id", type = IdType.AUTO)
    private Long id;

    /**
     * 批次号
     */
    private String batchNo;

    /**
     * 操作人
     */
    private String operator;

    /**
     * 操作时间
     */
    private LocalDateTime operateTime;

    /**
     * 操作类型 1-导入 2-修改
     */
    private Integer operateType;

    /**
     * 操作明细(导入-附件名称  修改-报单id)
     */
    private String operateDetail;

    /**
     * 附件地址(操作类型为修改 该字段为空)
     */
    private String attachmentUrl;

    /**
     * 上传状态 0-上传失败 1-上传成功 2-处理中
     */
    private Integer uploadStatus;


}

问：SnowOperateLogServiceImpl继承ServiceImpl就可以获得service层的方法，为什么还需要实现ISnowOperateLogService接口？

答：实现 ISnowOperateLogService 接口能够更方便地对业务进行扩展，一些复杂场景下的数据处理，MyBatisPlus 提供的 Service 方法可能无法处理，此时我们就需要自己编写代码，这时候只需在 ISnowOperateLogService 中定义自己的方法，并在 SnowOperateLogServiceImpl 中实现即可。具体见这行代码（SnowOperateLogServiceImpl类）：

List<SnowOperateLog> snowOperateLogs = operateLogMapper.selectAllByOperator(operator);

四、Wrapper中的QueryWrapper常用ge,gt,lt,le等具体含义

这个自己看源码就行，具体的类在是com.baomidou.mybatisplus.core.conditions.interfaces.interface

方法名	方法描述
allEq	map 所有非空属性等于 =
eq	等于 =
ne	不等于 <>
gt	大于 >
ge	大于等于 >=
lt	小于 <
le	小于等于 <=
between	ETWEEN 值1 AND 值2
notBetween	NOT BETWEEN 值1 AND 值2
like	LIKE '%值%'
notLike	NOT LIKE '%值%'
likeLeft	LIKE '%值'
likeRight	LIKE '值%'