Automating CRUD Operations with MyBatisPlus in Spring Boot

Even for simple CRUD, extracting a reusable component is straightforward; this guide shows how to automate CRUD using MyBatisPlus in a Spring Boot project.

First, add the MyBatisPlus starter dependency:

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.2</version>
</dependency>

Next, create a utility class ApprenticeUtil that provides methods for converting between camelCase and snake_case, building a QueryWrapper from an entity, and retrieving field values via reflection.

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ReflectionUtils;

import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Objects;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Apprentice system utilities
 */
public class ApprenticeUtil {
    private static Pattern humpPattern = Pattern.compile("[A-Z]");
    private static Pattern linePattern = Pattern.compile("_(\\w)");
    // ... (methods humpToLine, lineToHump, getQueryWrapper, getValueForClass)
}

Then define a generic BaseController that, through Spring MVC annotations, offers common RESTful endpoints for insert, delete, update, getById, save, list, page, and count operations. The controller uses the generic service S extends IService<E> and the entity type E.

import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.IService;
import com.wangfugui.apprentice.common.util.ApprenticeUtil;
import com.wangfugui.apprentice.common.util.ResponseUtils;
import com.wangfugui.apprentice.dao.dto.PageParamDto;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;

public class BaseController<S extends IService<E>, E> {
    @Autowired
    protected S baseService;
    // CRUD methods annotated with @PostMapping/@GetMapping
    // ... (insert, delete, updateById, getById, save, list, page, count)
}

Because MyBatisPlus does not enable pagination by default, add a configuration class that registers a PaginationInnerInterceptor for MySQL.

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;

@Configuration
public class MybatisPlusConfig {
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

Finally, create concrete controllers that extend BaseController, supplying the specific service and entity types. For example, a DynamicController and a BlogController can be defined with only the class declaration.

@RestController
@RequestMapping("/apprentice/dynamic")
@Api("Dynamic Management")
public class DynamicController extends BaseController<IDynamicService, Dynamic> {}

@RestController
@RequestMapping("/apprentice/blog")
@Api(tags = "Blog Management")
public class BlogController extends BaseController<IBlogService, Blog> {}

With these steps, the application gains a fully functional, reusable CRUD layer without writing repetitive code for each entity.