SpringBoot整合Mybatis Plus實(shí)現(xiàn)基本CRUD的示例代碼

更新時(shí)間：2023年05月11日 09:37:30 作者：JK凱

Mybatis Plus是在Mybatis的基礎(chǔ)上的增強(qiáng)，使得我們對一些基本的CRUD使用起來更方便，本文主要介紹了SpringBoot整合Mybatis Plus實(shí)現(xiàn)基本CRUD的示例代碼，具有一定的參考價(jià)值，感興趣的可以了解一下

對數(shù)據(jù)庫的操作是我們公司中必不可少的功能，Mybatis Plus是在Mybatis的基礎(chǔ)上的增強(qiáng)，使得我們對一些基本的CRUD使用起來更方便等，這篇文章主要講講SpringBoot如何去整合Mybatis Plus，并實(shí)現(xiàn)基本的CRUD功能。

一、引入相應(yīng)的依賴

<dependency>
  <groupId>com.baomidou</groupId>
  <artifactId>mybatis-plus-boot-starter</artifactId>
  <version>3.5.3.1</version>
</dependency>
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.32</version>
</dependency>

引入mybatis-plus的依賴和mysql驅(qū)動的依賴。

二、進(jìn)行配置

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb?characterEncoding=utf-8&serverTimeZone=UTC
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  global-config:
    db-config:
      id-type: auto
      logic-delete-field: deleted
      logic-delete-value: 1
      logic-not-delete-value: 0

spring.datasource是對數(shù)據(jù)庫的鏈接信息的配置

mybatis-plus:

configuration.log-impl: 配置打印sql日志
id-type: id主鍵生成策略，auto為自增
logic-delete-field: 邏輯刪除的字段，線上數(shù)據(jù)庫一般要配置邏輯刪除
logic-delete-value: 邏輯刪除已刪除的值
logic-not-delete-value: 邏輯刪除未刪除的值

三、新建數(shù)據(jù)庫表

這里我新建一張簡單的user表

sql如下：

DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) NOT NULL,
  `age` int(3) NOT NULL,
  `create_time` datetime DEFAULT NULL,
  `update_time` datetime DEFAULT NULL,
  `deleted` int(1) DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

可以看到表中有一些建表必須的字段create_time、update_time、deleted，前兩個(gè)字段我們需要在項(xiàng)目中配置一下Mybatis Plus讓他在我們新增數(shù)據(jù)，更新數(shù)據(jù)時(shí)自動插入值，deleted邏輯刪除字段因?yàn)槲覀円呀?jīng)在yml中配置了，后續(xù)我們都不需要再處理。

四、配置 Mybatis Plus 自動填充

配置 Mybatis Plus 自動填充來實(shí)現(xiàn)對create_time、update_time的值自動插入和更新。

新建handler.mybatisplus.MyMetaObjectHandler類
該類實(shí)現(xiàn)MetaObjectHandler接口
并重寫insertFille和updateFill方法

具體代碼實(shí)現(xiàn)如下:

handler.mybatisplus.MyMetaObjectHandler:

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import java.util.Date;
@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
    @Override
    public void insertFill(MetaObject metaObject) {
        setFieldValByName("createTime", new Date(), metaObject);
        setFieldValByName("updateTime", new Date(), metaObject);
    }
    @Override
    public void updateFill(MetaObject metaObject) {
        setFieldValByName("updateTime", new Date(), metaObject);
    }
}

五、實(shí)現(xiàn)User實(shí)體類、UserMapper、UserService

User實(shí)體類

domain.entity.User：

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;
import java.util.Date;
@Data
@AllArgsConstructor
@NoArgsConstructor
@Accessors(chain = true)
@TableName("user")
public class User {
    @TableId
    private Long id;
    private String username;
    private Integer age;
    @TableField(fill = FieldFill.INSERT)
    private Date createTime;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Date updateTime;
    private Integer deleted;
}

@TableName：指定實(shí)體類對應(yīng)的表名

@TableId：指定為主鍵，我們配置的是auto，即主鍵自增策略

@TableField：指定該值使用我們的自動填充策略，INSERT為插入時(shí)填充，INSERT_UPDATE為插入和更新時(shí)填充

UserMapper

mapper.UserMapper:

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.jk.domain.entity.User;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface UserMapper extends BaseMapper<User> {
}

繼承Mybatis Plus提供的BaseMapper，已經(jīng)實(shí)現(xiàn)了一些基本的CRUD接口

UserService

service.UserService:

public interface UserService {
}

service.impl.UserServiceImpl:

import com.jk.service.UserService;
import org.springframework.stereotype.Service;
@Service
public class UserServiceImpl implements UserService {
}

先把對應(yīng)的service建好，后面實(shí)現(xiàn)controller時(shí)再一并實(shí)現(xiàn)。

六、使用Restful風(fēng)格實(shí)現(xiàn)CRUD功能

前期準(zhǔn)備

因?yàn)槲覀冃枰诓榱斜頃r(shí)需要使用分頁功能，需要配置一下Mybatis Plus分頁插件

config.MybatisPlus:

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;
@Configuration
public class MybatisPlus {
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
        mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return mybatisPlusInterceptor;
    }
}

另外因?yàn)槲覀冃枰谛略龊透聲r(shí)是不需要全部的實(shí)體字段，需要創(chuàng)建對應(yīng)的DTO來接收前端數(shù)據(jù)，返回時(shí)也不需要全部字段，需要對應(yīng)的Vo對返回前端所需字段

domain.dto.AddUserDto:

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class AddUserDto {
    private String username;
    private Integer age;
}

domain.dto.UpdateUserDto:

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class UpdateUserDto {
    private Long id;
    private String username;
    private Integer age;
}

domain.vo.UserVo:

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.util.Date;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class UserVo {
    private Long id;
    private String username;
    private Integer age;
    private Date createTime;
}

domain.vo.PageVo:

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.util.List;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class PageVo {
    private List result;
    private Long total;
}

PageVo用來處理所有需要分頁數(shù)據(jù)的響應(yīng)

關(guān)于統(tǒng)一響應(yīng)大家可以看 SpringBoot 中統(tǒng)一響應(yīng)格式及統(tǒng)一異常處理，你應(yīng)該這樣做

關(guān)于Bean拷貝大家可以看SpringBoot 項(xiàng)目中 Bean 拷貝及工具類封裝

CRUD 對應(yīng)的controller

controller.UserController:

import com.jk.domain.dto.AddUserDto;
import com.jk.domain.dto.UpdateUserDto;
import com.jk.service.UserService;
import com.jk.domain.vo.ResponseResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;
    @PostMapping
    public ResponseResult addUser(@RequestBody AddUserDto addUserDto) {
        return userService.addUser(addUserDto);
    }
    @PutMapping
    public ResponseResult updateUser(@RequestBody UpdateUserDto updateUserDto) {
        return userService.updateUser(updateUserDto);
    }
    @DeleteMapping("/{id}")
    public ResponseResult deleteUser(@PathVariable("id") Long id) {
        return userService.deleteUser(id);
    }
    @GetMapping
    public ResponseResult getUser(@RequestParam(defaultValue = "1") Integer pageNum,
                                  @RequestParam(defaultValue = "10") Integer pageSize) {
        return userService.getUser(pageNum, pageSize);
    }
}

CRUD 對應(yīng)的 service

service.UserService:

import com.jk.domain.dto.AddUserDto;
import com.jk.domain.dto.UpdateUserDto;
import com.jk.domain.vo.ResponseResult;
public interface UserService {
    ResponseResult addUser(AddUserDto addUserDto);
    ResponseResult updateUser(UpdateUserDto updateUserDto);
    ResponseResult deleteUser(Long id);
    ResponseResult getUser(Integer pageNum, Integer pageSize);
}

CRUD 都應(yīng) service實(shí)現(xiàn)類

service.impl.UserServiceImpl:

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.jk.domain.dto.AddUserDto;
import com.jk.domain.dto.UpdateUserDto;
import com.jk.domain.entity.User;
import com.jk.domain.vo.UserVo;
import com.jk.mapper.UserMapper;
import com.jk.service.UserService;
import com.jk.domain.vo.PageVo;
import com.jk.domain.vo.ResponseResult;
import com.jk.utils.BeanCopyUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;
    @Override
    public ResponseResult addUser(AddUserDto addUserDto) {
        User user = BeanCopyUtils.copyBean(addUserDto, User.class);
        userMapper.insert(user);
        return ResponseResult.okResult();
    }
    @Override
    public ResponseResult updateUser(UpdateUserDto updateUserDto) {
        User user = new User();
        BeanUtils.copyProperties(updateUserDto, user);
        userMapper.updateById(user);
        return ResponseResult.okResult();
    }
    @Override
    public ResponseResult deleteUser(Long id) {
        userMapper.deleteById(id);
        return ResponseResult.okResult();
    }
    @Override
    public ResponseResult getUser(Integer pageNum, Integer pageSize) {
        Page<User> userPage = new Page<>(pageNum, pageSize);
        userMapper.selectPage(userPage, null);
        List<UserVo> userVos = BeanCopyUtils.copyBeanList(userPage.getRecords(), UserVo.class);
        PageVo pageVo = new PageVo(userVos, userPage.getTotal());
        return ResponseResult.okResult(pageVo);
    }
}

到此這篇關(guān)于SpringBoot整合Mybatis Plus實(shí)現(xiàn)基本CRUD的示例代碼的文章就介紹到這了,更多相關(guān)SpringBoot MybatisPlus實(shí)現(xiàn)CRUD內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

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