概述

MybatisPlus是国产的第三方插件， 它封装了许多常用的CURDapi，免去了我们写mapper.xml的重复劳动，这里介绍了基本的整合SpringBoot和基础用法。

引入依赖

在项目中pom文件引入mybatisplus和mysql驱动依赖，如下图

    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.5.1</version>
    </dependency>
     <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
         <version>8.0.26</version>
     </dependency>

配置连接信息

在项目中application.yaml文件中配置数据库的连接信息

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/didiadmin?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8&nullCatalogMeansCurrent=true
    username: root
    password: 123456

新建两个表

本案例通过一个完整的业务流程来介绍如何使用mybatispuls，首先在数据库中新建两个表，一个是字典类型表sys_dict_type和一个字典数据表sys_dict_data

CREATE TABLE `sys_dict_type` (
    `id` CHAR (19) CHARACTER
    SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '标识',
    `type_name` VARCHAR (255) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '字典类型名称',
 `type_code` VARCHAR (255) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '字典类型标识',
 `description` VARCHAR (255) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '字典类型描述',
 `enable` CHAR (1) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '是否启用',
 `create_by` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '创建人ID',
  `create_name` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '创建人名称',
 `create_time` datetime DEFAULT NULL COMMENT '创建时间',
 `update_by` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '修改人ID',
 `update_name` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '修改人名称',
 `update_time` datetime DEFAULT NULL COMMENT '修改时间',
 `remark` VARCHAR (255) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '备注',
 PRIMARY KEY (`id`) USING BTREE
) ENGINE = INNODB DEFAULT CHARSET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = DYNAMIC

CREATE TABLE `sys_dict_data` (
    `data_id` CHAR (19) CHARACTER
    SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '标识',
    `data_label` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '字典标签',
 `data_value` CHAR (20) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '字典值',
 `type_code` CHAR (20) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '所属类型',
 `is_default` CHAR (1) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '是否默认',
 `update_by` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '修改人ID',
   `update_name` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '修改人名称',
 `update_time` datetime DEFAULT NULL COMMENT '修改时间',
 `create_by` VARCHAR (255) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '创建人ID',
   `create_name` CHAR (19) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '创建人名称',
 `create_time` datetime DEFAULT NULL COMMENT '创建时间',
 `remark` VARCHAR (255) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '备注',
 `enable` CHAR (1) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '是否启用',
 PRIMARY KEY (`data_id`) USING BTREE
) ENGINE = INNODB DEFAULT CHARSET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = DYNAMIC

在项目中创建相应的实体类

通过观察SQL语句发现两个表中有很多相同的字段，所有我们把相同的字段抽离出来，放到一个基础的实体类中，其他实体类通过集成方式获取公共的字段。

创建基础实体类

package com.didiplus.common.base;

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import lombok.Data;

import java.io.Serializable;
import java.time.LocalDateTime;

/**
* Author: didiplus
* Email: 972479352@qq.com
* CreateTime: 2022/4/29
* Desc: 基 础 实 体 类
*/

@Data
public class BaseDomain implements Serializable {
   
   

    /**
    * 创建时间
    */
    @TableField(value = "create_time", fill = FieldFill.INSERT)
    private LocalDateTime createTime;

    /**
    * 创建人
    */
    @TableField(value = "create_by", fill = FieldFill.INSERT)
    private String createBy;

    /**
    * 创建人名称
    */
    @TableField(value = "create_name", fill = FieldFill.INSERT)
    private String createName;

    /**
    * 修改时间
    */
    @TableField(value = "update_time", fill = FieldFill.UPDATE)
    private LocalDateTime updateTime;

    /**
    * 修改人
    */
    @TableField(value = "update_by", fill = FieldFill.UPDATE)
    private String updateBy;

    /**
    * 修改人名称
    */
    @TableField(value = "update_name", fill = FieldFill.UPDATE)
    private String updateName;


    /**
    * 备注
    */
    private String remark;
}

@TableField 是mybatisplus中的一个注解，后面会讲解到的。

基础实体类创建好了，接着我们把剩下的两个实体类也一同创建吧。

SysDictType实体类

package com.didiplus.modules.sys.domain;

import com.didiplus.common.base.BaseDomain;
import com.didiplus.common.base.ValidGroup;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

import javax.validation.constraints.*;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/25
 * Desc: 字典类型领域模型
 */

@Data
@ApiModel(value = "字典类型")
public class SysDictType extends BaseDomain {
   
   

    /**
     * 标识
     */
    @Null(groups = ValidGroup.Crud.Create.class)
    @NotNull(groups = ValidGroup.Crud.Update.class,message = "字典ID不能为空")
    @ApiModelProperty("ID")
    private String id;

    /**
     * 字典名称
     */
    @NotBlank(message = "字典名称必填项")
    @ApiModelProperty(value = "字典名称",example = "用户ID")
    private String typeName;
    /**
     * 字典类型
     */
    @NotBlank(message = "字典编码不能为空")
    @ApiModelProperty(value = "字典编码")
    private String typeCode;
    /**
     * 字典描述
     */
    @ApiModelProperty(value = "字典描述")
    private String description;
    /**
     * 字典可用状态
     */
    @NotBlank(message = "字典状态不能为空")
    @ApiModelProperty(value = "字典状态")
    private Boolean enable;
}

SysDictData实体类

package com.didiplus.modules.sys.domain;

import com.baomidou.mybatisplus.annotation.TableField;
import com.didiplus.common.base.BaseDomain;
import com.didiplus.common.base.ValidGroup;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Null;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/29
 * Desc: 字典值领域模型
 */

@Data
public class SysDictData extends BaseDomain {
   
   
    /**
     * id 编号
     */
    @Null(groups = ValidGroup.Crud.Create.class)
    @NotNull(groups = ValidGroup.Crud.Update.class,message = "字典数据ID不能为空")
    @ApiModelProperty("ID")
    @TableField(value = "data_id")
    private String dataId;
    /**
     * 字典显示
     */
    @NotBlank(message = "字典数据名称必填项")
    @ApiModelProperty(value = "字典数据名称")
    private String dataLabel;
    /**
     * 字典值
     */
    @NotBlank(message = "字典数据值不能为空")
    @ApiModelProperty(value = "字典数据值")
    private String dataValue;
    /**
     * 字典类型
     */
    @ApiModelProperty(value = "字典编码")
    @NotBlank(message = "字典数据值不能为空")
    private String typeCode;
    /**
     * 是否为默认
     */
    @ApiModelProperty(value = "字典编码")
    @NotBlank(message = "字典数据值不能为空")
    private String isDefault;

    /**
     * 是否启用
     */
    @NotBlank(message = "字典状态不能为空")
    @ApiModelProperty(value = "字典数据状态")
    private Boolean enable;
}

创建DAO继承MybatisPlus增强接口

为两个实体类中分别添加DAO继承MybatisPlus增强接口，这样就可以集成了增删改查的功能了。

SysDictTypeMapper

package com.didiplus.modules.sys.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.didiplus.modules.sys.domain.SysDictType;
import org.apache.ibatis.annotations.Mapper;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/29
 * Desc: 字典类型接口
 */
@Mapper
public interface SysDictTypeMapper extends BaseMapper<SysDictType> {
   
   
}

SysDictDataMapper

package com.didiplus.modules.sys.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.didiplus.modules.sys.domain.SysDictData;
import org.apache.ibatis.annotations.Mapper;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/29
 * Desc: 字典数据接口
 */

@Mapper
public interface SysDictDataMapper extends BaseMapper<SysDictData> {
   
   
}

进一步封装到Service层

定义Service接口中的抽象方法

SysDictDataService

package com.didiplus.modules.sys.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.didiplus.modules.sys.domain.SysDictData;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/29
 * Desc:
 */

public interface SysDictDataService extends IService<SysDictData> {
   
   
}

SysDictTypeService

package com.didiplus.modules.sys.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.didiplus.modules.sys.domain.SysDictType;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/29
 * Desc:
 */
public interface SysDictTypeService extends IService<SysDictType> {
   
   
}

实现Service接口中的方法

SysDictTypeServiceImpl

package com.didiplus.modules.sys.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.didiplus.modules.sys.domain.SysDictType;
import com.didiplus.modules.sys.mapper.SysDictTypeMapper;
import com.didiplus.modules.sys.service.SysDictTypeService;
import org.springframework.stereotype.Service;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/29
 * Desc:
 */
@Service
public class SysDictTypeServiceImpl extends ServiceImpl<SysDictTypeMapper, SysDictType> implements SysDictTypeService {
   
   
}

SysDictDataServiceImpl

package com.didiplus.modules.sys.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.didiplus.modules.sys.domain.SysDictType;
import com.didiplus.modules.sys.mapper.SysDictTypeMapper;
import com.didiplus.modules.sys.service.SysDictTypeService;
import org.springframework.stereotype.Service;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/29
 * Desc:
 */
@Service
public class SysDictTypeServiceImpl extends ServiceImpl<SysDictTypeMapper, SysDictType> implements SysDictTypeService {
   
   
}

在控制层上进行增删改查操作

SysDictTypeController

package com.didiplus.modules.sys.controller;

import com.didiplus.common.base.ValidGroup;
import com.didiplus.modules.sys.domain.SysDictType;
import com.didiplus.modules.sys.service.SysDictTypeService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.v3.oas.annotations.parameters.RequestBody;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;


/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/4/25
 * Desc: 数据字典控制器
 */
@RestController
@Api(tags = "数据字典")
@RequestMapping("/api/sys/dictType")
public class SysDictTypeController {
   
   

    @Autowired
    SysDictTypeService sysDictTypeService;

    @ApiOperation("字典添加")
    @PostMapping("/add")
    public String add(@Validated(value = ValidGroup.Crud.Create.class) @RequestBody SysDictType sysDictType) {
   
   
        return  sysDictTypeService.save(sysDictType)? "添加成功":"添加失败";
    }

    @ApiOperation("字典修改")
    @PutMapping("/edit")
    public String edit(@Validated(value = ValidGroup.Crud.Update.class) @RequestBody SysDictType sysDictType) {
   
   
        return  sysDictTypeService.updateById(sysDictType)? "修改成功":"修改失败";
    }


    @ApiOperation("字典删除")
    @DeleteMapping("/del/{id}")
    public  String del( @PathVariable String id) {
   
   
        return  sysDictTypeService.removeById(id)? "删除成功":"删除失败";
    }


}

体验效果

新增数据

修改数据

删除数据

自动填充功能

原理:

• 实现元对象处理器接口：com.baomidou.mybatisplus.core.handlers.MetaObjectHandler
• 注解填充字段 @TableField(.. fill = FieldFill.INSERT)生成器策略部分也可以配置！

  自定义实现类 DomainInterceptor

  ```java
  package com.didiplus.common.web.interceptor;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;

/**

• Author: didiplus
• Email: 972479352@qq.com
• CreateTime: 2022/5/4

• Desc: 字 段 填 充 拦 截 器
  */
  @Component
  public class DomainInterceptor implements MetaObjectHandler {
  @Override
  public void insertFill(MetaObject metaObject) {

   createField(metaObject);
  

  }

  @Override
  public void updateFill(MetaObject metaObject) {

   updateField(metaObject);
  

  }

  /**

  • @Field 创建时间

  • */
    public void createField(MetaObject metaObject){
    this.strictInsertFill(metaObject,"createTime", LocalDateTime.class,LocalDateTime.now());
    }

    /**

  • @Field 修改时间
  • */
    public void updateField(MetaObject metaObject) {
    this.strictUpdateFill(metaObject,"updateTime",LocalDateTime.class,LocalDateTime.now());
    }
    }
    ```

    分页查询

    添加分页插件

    ```java
    package com.didiplus.common.config;

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

/**

• Author: didiplus
• Email: 972479352@qq.com
• CreateTime: 2022/5/4

• Desc: mybatis-plus分页插件
  */
  @Configuration
  public class MyBatisPlusConfig {

  /**

  • mybatis-plus分页插件
    */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
    MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
    interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
    return interceptor;
    }
    }
    ```

    定义分页接口

    ```java
    package com.didiplus.modules.sys.service;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.IService;
import com.didiplus.common.web.domain.PageDomain;
import com.didiplus.modules.sys.domain.SysDictType;

/**

• Author: didiplus
• Email: 972479352@qq.com
• CreateTime: 2022/4/29

• Desc: 数据字典类型服务类
  */
  public interface SysDictTypeService extends IService {

  IPage page(PageDomain pageDomain);
  }
  ```

  实现分页接口

  ```java
  package com.didiplus.modules.sys.service.impl;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.didiplus.common.web.domain.PageDomain;
import com.didiplus.modules.sys.domain.SysDictType;
import com.didiplus.modules.sys.mapper.SysDictTypeMapper;
import com.didiplus.modules.sys.service.SysDictTypeService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

/**

• Author: didiplus
• Email: 972479352@qq.com
• CreateTime: 2022/4/29

• Desc:
  */
  @Service
  public class SysDictTypeServiceImpl extends ServiceImpl implements SysDictTypeService {
  @Resource
  SysDictTypeMapper sysDictTypeMapper;
  @Override
  public IPage page(PageDomain pageDomain) {

   IPage<SysDictType> page = new Page<>(pageDomain.getPage(),pageDomain.getLimit());
   return sysDictTypeMapper.selectPage(page,null);
  

  }
  }

  ## 控制层调用
  ```java
  @RestController
  @Api(tags = "数据字典")
  @RequestMapping("/api/sys/dictType")
  public class SysDictTypeController {
  
   @Autowired
   SysDictTypeService sysDictTypeService;
  
   @ApiOperation("字典分页查询")
   @GetMapping
   public IPage list(@RequestBody PageDomain pageDomain){
       return sysDictTypeService.page(pageDomain);
   }
  }
  

  PageDomain定义了分页接收的两个参数

PageDomain类

package com.didiplus.common.web.domain;

import lombok.Data;

/**
 * Author: didiplus
 * Email: 972479352@qq.com
 * CreateTime: 2022/5/4
 * Desc: 分 页 参 数 封 装
 */
@Data
public class PageDomain {
   
   
    /**
     * 当前页
     */
    private  Integer page;
    /**
     * 每页数量
     */
    private  Integer limit;

}

体验效果

下一篇，我们继续来学习mybatisPlus的代码生成器