SpringBoot整合MybatisPlus基本的增删改查，保姆级教程

　　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。2|0引入依赖
　　在项目中pom  文件引入mybatisplus  和mysql  驱动依赖，如下图             com.baomidou         mybatis-plus-boot-starter         3.5.1                     mysql          mysql-connector-java          8.0.26       3|0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 4|0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 5|0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。5|1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。5|2SysDictType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; }  5|3SysDictData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; } 6|0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。6|1SysDictTypeMapperpackage 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 { } 6|2SysDictDataMapperpackage 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 { } 7|0进一步封装到Service层7|1定义Service接口中的抽象方法SysDictDataServicepackage 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 { } SysDictTypeServicepackage 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 { }  7|2实现Service接口中的方法SysDictTypeServiceImplpackage 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 implements SysDictTypeService { }  SysDictDataServiceImplpackage 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 implements SysDictTypeService { }  8|0在控制层上进行增删改查操作8|1SysDictTypeControllerpackage 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
　　9|0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！9|1自定义实现类 DomainInterceptorpackage 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());     } } 10|0分页查询10|1添加分页插件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;     } } 10|2定义分页接口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); } 10|3实现分页接口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 page = new Page<>(pageDomain.getPage(),pageDomain.getLimit());         return sysDictTypeMapper.selectPage(page,null);     } } 10|4控制层调用@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;  } 10|5体验效果
　　下一篇，我们继续来学习mybatisPlus的代码生成器
　　原文链接：SpringBoot整合MybatisPlus基本的增删改查，保姆级教程 - 北根娃 - 博客园