MybatisPlus查询更so easy

前言

MybatisPlus已经比Mybatis好用太多了，少了很多模板代码。但是使用多了，总是感觉仍然有很多模板代码要处理。昨天搞了SpringJPA以后，想了想，MybatisPlus也能so easy

现状

如果是普通的eq，直接可以使用Wrappers.query(entity)实现。但是in，between的查询也很常见，仍然需要写一些逻辑

环境

JDK1.8
SpringBoot2.7.11
mybatis-plus-boot-starter3.4.2
mysql-connector-j8.0.33

核心代码

调用queryWrapper方法， 入参为构造的参数对象和实体类型，返回查询条件

import cn.hutool.core.util.ObjectUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.TableFieldInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.db.query.Range;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.reflect.FieldUtils;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.stream.Collectors;

/**
 * @author dzh
 * @since 2024/12/30
 */
public class QueryMybatisPlusUtils {

    public static <T> QueryWrapper<T> queryWrapper(Object param, Class<T> entityType) {
        Field[] fields = FieldUtils.getAllFields(param.getClass());
        QueryWrapper<T> qr = Wrappers.query();
        try {
            for (Field field : fields) {
                field.setAccessible(true);
                String name = toColumnName(field.getName(), entityType);
                Class<?> type = field.getType();
                Object value = field.get(param);
                if (ObjectUtil.isNotEmpty(value)) {
                    if (value instanceof Range) {
                        Range<?> range = (Range<?>) value;
                        if (ObjectUtils.allNotNull(range.getMinimum(), range.getMaximum())) {
                            qr.between(name, range.getMinimum(), range.getMaximum());
                        } else if (range.getMinimum() != null) {
                            qr.ge(name, range.getMinimum());
                        } else if (range.getMaximum() != null) {
                            qr.le(name, range.getMaximum());
                        }
                    } else if (type.isPrimitive()) {
                        qr.eq(name, value);
                    } else if (value instanceof Collection) {
                        Collection<?> collection = (Collection<?>) value;
                        qr.in(name, collection);
                    } else if (value.getClass().isArray()) {
                        Collection<?> collection = Arrays.stream(((Object[]) value)).collect(Collectors.toList());
                        qr.in(name, collection);
                    }
                }
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return qr;
    }

    public static String toColumnName(String name, Class<?> type) {
        TableInfo tableInfo = TableInfoHelper.getTableInfo(type);
        if (tableInfo.getKeyProperty().equals(name)) {
            return tableInfo.getKeyColumn();
        }
        List<TableFieldInfo> fieldList = tableInfo.getFieldList();
        return fieldList.stream()
                .filter(item -> item.getField().getName().equals(name))
                .findAny()
                .map(TableFieldInfo::getColumn)
                .orElseThrow(() -> new RuntimeException("字段不存在：" + name));
    }
}

业务和测试代码

• 测试代码

    @Test
    void query() {
        BookQuery bookQuery = new BookQuery();
        QueryWrapper<Book> queryWrapper = QueryMybatisPlusUtils.queryWrapper(bookQuery, Book.class);
        System.out.println(queryWrapper);
        List<Book> books = bookMapper.selectList(queryWrapper);
        System.out.println(books);
    }

• Book 实体

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.apache.solr.client.solrj.beans.Field;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

import java.time.LocalDate;
import java.util.Date;

/**
 * @author dzh
 * @since 2024/10/22
 */
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
@Document("books")
@org.springframework.data.elasticsearch.annotations.Document(indexName = "books")
public class Book {
    @Id
    @TableId(type = IdType.AUTO)
    private Integer id;
    private String line;
    private Long pid;
    private String title;
    private Integer age;
    private LocalDate publishDay;
    private Date createTime;
}

• BookQuery 查询参数

import java.time.LocalDate;
import java.util.Date;
import java.util.List;

/**
 * @author dzh
 * @since 2024/12/30
 */
@Data
public class BookQuery {
    private List<Long> id;
    private List<String> title;
    private Range<Integer> age;
    private Range<LocalDate> publishDay;
    private Range<Date> createTime;
}

• Range 辅助区间查询类

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * 区间
 * @author dzh
 * @since 2024/12/31
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Range<T> {
    private T minimum;
    private T maximum;

    public static <T> Range<T> between(T minimum, T maximum) {
        return new Range<>(minimum, maximum);
    }
}

• BookMapper

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.db.entity.Book;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface BookMapper extends BaseMapper<Book> {
}

总结

这个只是懒人想的懒办法，技术能力有限，后续项目迭代中可以持续优化