MybatisPlus is not easy to use, the handsome guy wrote a MybatisPlusPro in a fit of anger

When Fugui is using MybatisPlusit for development, although it is easy to use, most of them are adding, deleting, modifying and checking at the dao level, so I plan to extract a set of functions in the controller layer by myself. Let me introduce first, " ": just inherit MybatisPlusProa BaseControllerclass , you can add, delete, modify, query, list query, page query, sort, query with parameters, and count the number. Without further ado, let's start!

The first step is to introduce the jar package of MybatisPlus

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

The second step is to write the util class

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系统Util
 *
 * @author MaSiyi
 * @version 1.0.0 2021/11/26
 * @since JDK 1.8.0
 */
public class ApprenticeUtil {

    private static Pattern humpPattern = Pattern.compile("[A-Z]");
    private static Pattern linePattern = Pattern.compile("_(\\w)");

    /**
     * 驼峰转下划线
     *
     * @Param: [str]
     * @return: java.lang.String
     * @Author: MaSiyi
     * @Date: 2021/11/26
     */
    public static String humpToLine(String str) {
        Matcher matcher = humpPattern.matcher(str);
        StringBuffer sb = new StringBuffer();
        while (matcher.find()) {
            matcher.appendReplacement(sb, "_" + matcher.group(0).toLowerCase());
        }
        matcher.appendTail(sb);
        return sb.toString();
    }

    /**
     * 下划线转驼峰
     *
     * @Param: [str]
     * @return: java.lang.String
     * @Author: MaSiyi
     * @Date: 2021/11/26
     */
    public static String lineToHump(String str) {
        str = str.toLowerCase();
        Matcher matcher = linePattern.matcher(str);
        StringBuffer sb = new StringBuffer();
        while (matcher.find()) {
            matcher.appendReplacement(sb, matcher.group(1).toUpperCase());
        }
        matcher.appendTail(sb);
        return sb.toString();
    }

    /**
     * 获取QueryWrapper
     *
     * @Param: [entity]
     * @return: com.baomidou.mybatisplus.core.conditions.query.QueryWrapper<E>
     * @Author: MaSiyi
     * @Date: 2021/11/26
     */
    public static <E> QueryWrapper<E> getQueryWrapper(E entity) {
        Field[] fields = entity.getClass().getDeclaredFields();
        QueryWrapper<E> eQueryWrapper = new QueryWrapper<>();
        for (int i = 0; i < fields.length; i++) {
            Field field = fields[i];
            //忽略final字段
            if (Modifier.isFinal(field.getModifiers())) {
                continue;
            }
            field.setAccessible(true);
            try {
                Object obj = field.get(entity);
                if (!ObjectUtils.isEmpty(obj)) {
                    String name = ApprenticeUtil.humpToLine(field.getName());
                    eQueryWrapper.eq(name, obj);
                }
            } catch (IllegalAccessException e) {
                return null;
            }
        }
        return eQueryWrapper;

    }

    /** 反射获取字段值
     * @Param: [entity, value] value 值为 "id" "name" 等
     * @return: java.lang.Object
     * @Author: MaSiyi
     * @Date: 2021/11/26
     */
    public static <E> Object getValueForClass(E entity,String value) {

        Field id = null;
        PropertyDescriptor pd = null;
        try {
            id = entity.getClass().getDeclaredField(value);
            pd = new PropertyDescriptor(id.getName(), entity.getClass());
        } catch (NoSuchFieldException | IntrospectionException e) {
            e.printStackTrace();
        }
        //获取get方法
        Method getMethod = Objects.requireNonNull(pd).getReadMethod();
        return ReflectionUtils.invokeMethod(getMethod, entity);
    }
}

Reflection to get the field value, this Java code demonstrates how to use reflection to get the property value of the specified object. A generic representation of a method that can accept parameters of any type entity. In this code, first obtain entitythe attributes of the class corresponding to the parameter object through reflection, ie value.

Then obtain idthe property's JavaBean specification accessor PropertyDescriptor through the built-in Introspector mechanism of Java, and extract the corresponding getter method from the object. Finally, use the tool class ReflectionUtils provided by the Spring framework to get the method and then call the getter method to get the attribute value and return it. It should be noted that if you want to access private member variables or methods under the reflection mechanism, you should first call its setAccessible(true) method to obtain permission.

In the third step, we write the BaseController class

Below is our BaseController class

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.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.List;

/** 核心公共controller类
 * @Param:
 * @return:
 * @Author: MaSiyi
 * @Date: 2021/11/26
 */
public class BaseController<S extends IService<E>, E> {

    @Autowired
    protected S baseService;

    @ApiOperation("增")
    @PostMapping("/insert")
    public ResponseUtils insert(@RequestBody E entity) {
        baseService.save(entity);
        return ResponseUtils.success("添加成功");
    }

    @ApiOperation("删")
    @PostMapping("/deleteById")
    public ResponseUtils delete(@RequestBody List<Integer> ids) {

        baseService.removeByIds(ids);
        return ResponseUtils.success("添加成功");
    }

    @ApiOperation("改")
    @PostMapping("/updateById")
    public ResponseUtils updateById(@RequestBody E entity) {
        baseService.updateById(entity);
        return ResponseUtils.success("添加成功");
    }

    @ApiOperation("查")
    @GetMapping("/getById")
    public ResponseUtils getById(@RequestParam Integer id) {

        return ResponseUtils.success(baseService.getById(id));
    }

    @ApiOperation("存")
    @PostMapping("/save")
    public ResponseUtils save(@RequestBody E entity) {
        baseService.saveOrUpdate(entity);
        return ResponseUtils.success("添加成功");
    }

    @ApiOperation("list查")
    @PostMapping("/list")
    public ResponseUtils list(@RequestBody E entity) {
        QueryWrapper<E> queryWrapper = ApprenticeUtil.getQueryWrapper(entity);
        List<E> list = baseService.list(queryWrapper);
        return ResponseUtils.success(list);
    }

    @ApiOperation("page查")
    @PostMapping("/page")
    public ResponseUtils page(@RequestBody PageParamDto<E> pageParamDto) {
        //限制条件
        if (pageParamDto.getPage() < 1) {
            pageParamDto.setPage(1);
        }

        if (pageParamDto.getSize() > 100) {
            pageParamDto.setSize(100);
        }
        Page<E> page = new Page<>(pageParamDto.getPage(), pageParamDto.getSize());
        QueryWrapper<E> queryWrapper = new QueryWrapper<>();
        //升序
        String asc = pageParamDto.getAsc();
        if (!StrUtil.isEmpty(asc) && !"null".equals(asc)) {
            String[] split = asc.split(",");
            queryWrapper.orderByAsc(split);
        }
        //降序
        String desc = pageParamDto.getDesc();
        if (!StrUtil.isEmpty(desc) && !"null".equals(desc)) {
            String[] split = desc.split(",");
            queryWrapper.orderByDesc(split);
        }
        Page<E> ePage = baseService.page(page, queryWrapper);
        return ResponseUtils.success(ePage);
    }

    @ApiOperation("获取数量")
    @PostMapping("/count")
    public ResponseUtils count(@RequestBody E entity) {
        QueryWrapper<E> queryWrapper = ApprenticeUtil.getQueryWrapper(entity);
        long count = baseService.count(queryWrapper);
        return ResponseUtils.success(count);
    }


}

This Java code shows a basic RESTful API interface implementation based on the Spring Boot framework. BaseController is a more general Controller base class, which can handle requests corresponding to various entity types (such as adding, deleting, modifying, checking, etc.) through generics.

具体来说，该类中包含了五个基本HTTP操作（POST, GET），通过不同参数和请求方式对实体对象进行CRUD操作，即添加(insert)、删除(delete)、修改(update)、查询(getById)、存储(save)、列表查询(list)、分页查询(page)、统计数量(count)。同时，通过Spring Boot自带的Web开发框架中的注解，将每个方法暴露为一个Restful API。

需要注意的是，该控制器只是一个模板，实际使用时需要继承该控制器并传入相应的Service类作为泛型S的参数，并实现具体的CRUD方法。

第四步，由于mybatisplus默认是不支持分页的，我们需要配置一下使他支持

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 {


    /** 设置分页插件
     * @Param: []
     * @return: com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor
     * @Author: MaSiyi
     * @Date: 2021/11/26
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
    
}

第五步，我们在自己的controller类中继承BaseController类

import com.wangfugui.apprentice.dao.domain.Dynamic;
import com.wangfugui.apprentice.service.IDynamicService;
import io.swagger.annotations.Api;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * <p>
 * 动态表 前端控制器
 * </p>
 *
 * @author MrFugui
 * @since 2021-11-23
 */
@RestController
@RequestMapping("/apprentice/dynamic")
@Api("动态管理")
public class DynamicController extends BaseController<IDynamicService, Dynamic>{

}

这样就可以有默认的增删改查了

import com.wangfugui.apprentice.dao.domain.Blog;
import com.wangfugui.apprentice.service.IBlogService;
import io.swagger.annotations.Api;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * <p>
 * 博客表 前端控制器
 * </p>
 *
 * @author MrFugui
 * @since 2021-11-25
 */
@RestController
@RequestMapping("/apprentice/blog")
@Api(tags = "博客管理")
public class BlogController extends BaseController<IBlogService, Blog>{



}

这样就能使用啦！ 仓库地址： MybatisPlusPro 如果对你有用的话，记得关注一下富贵同学，爱你们