不同查询构建器的使用方式（Mybatis、Mybatis-Plus、Mybatis-Flex、Spring Data JPA、QueryDsl）

- 一、SQL查询需求
- 二、【Mybaits】xml方式
- 三、【Mybatis-Plus】QueryWrapper方式
- 四、【Mybatis-Flex】QueryWrapper方式
- 五、【Mybatis-Flex】QueryWrapper & APT方式
- 六、【Spring Data JPA】Specification方式
- 七、【Spring Data JPA】Specification & MetaModel方式
- 八、【Spring Data JPA】QueryDsl方式

一、SQL查询需求

实现如下3个查询：

-- 查询1
SELECT 
* 
FROM SAMPLE 
WHERE
id = 1 
AND name LIKE '%ha%' 
AND create_time BETWEEN '2014-11-24' AND '2024-11-24'  

-- 查询2
SELECT 
* 
FROM SAMPLE 
WHERE
id = 1 
OR name LIKE '%ha%' 
OR create_time BETWEEN '2014-11-24' AND '2024-11-24'  

-- 查询3
SELECT 
* 
FROM SAMPLE 
WHERE
( id = 1 OR name LIKE '%ha%')
AND create_time BETWEEN '2014-11-24' AND '2024-11-24'

查询参数：

package com.luo.query;

class SampleQuery {
	private Long id;
	private String name;
	private LocalDateTime startDate;
	private LocalDateTime endDate;
	//省略getter/setter...
}

Sample数据对象：

package com.luo.po;

class Sample {
	private Long id;
	private String name;
	private LocalDateTime createTime;
	//省略getter/setter...
}

二、【Mybaits】xml方式

定义dao接口：

package com.luo.dao;

class SamplerMapper {
	List<Sample> select1(SampleQuery query);
	List<Sample> select2(SampleQuery query);
	List<Sample> select3(SampleQuery query);
}

定义mapper.xml，使用xml编写动态sql条件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.luo.dao.SampleMapper">   
    <select id="select1" resultType="com.luo.po.Sample">
        SELECT *
        FROM SAMPLE
        <where>
            <if test="id != null">
                AND id = #{id}
            </if>
            <if test="name != null">
                AND name LIKE CONCAT('%',#{name},'%')
            </if>
            <if test="startDate != null and endDate != null">
                AND create_time BETWEEN #{startDate} AND #{endDate}
            </if>
        </where>
    </select>
	<select id="select2" resultType="com.luo.po.Sample">
        SELECT *
        FROM SAMPLE
        <where>
            <if test="id != null">
                OR id = #{id}
            </if>
            <if test="name != null">
                OR name LIKE CONCAT('%',#{name},'%')
            </if>
            <if test="startDate != null and endDate != null">
                OR create_time BETWEEN #{startDate} AND #{endDate}
            </if>
        </where>
    </select>
    <select id="select3" resultType="com.luo.po.Sample">
        SELECT *
        FROM SAMPLE
        <where>
        	<if test="id != null or name != null">
        	(
	        	<if test="id != null">
	                id = #{id} OR 
	            </if>
	            <if test="name != null">
	                name LIKE CONCAT('%',#{name},'%')
	            </if>
	        )
        	</if>            
            <if test="startDate != null and endDate != null">
                AND create_time BETWEEN #{startDate} AND #{endDate}
            </if>
        </where>
    </select>
</mapper>

三、【Mybatis-Plus】QueryWrapper方式

定义dao接口，使用Mybatis-Plus QueryWrapper 动态构建查询条件：

import com.baomidou.mybatisplus.core.mapper.BaseMapper
import com.baomidou.mybatisplus.core.toolkit.Wrappers;

public interface SampleMapper extends BaseMapper<Sample> {

    default List<Sample> select1(SampleQueryDto query) {
        return this.selectList(Wrappers.<Sample>lambdaQuery()
                .eq(Objects.nonNull(query.getId()), Sample::getId, query.getId())
                .like(Objects.nonNull(query.getName()), Sample::getName, query.getName())
                .between(Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate()), Sample::getCreateTime, query.getStartDate(), query.getEndDate())
        );
    }

    default List<Sample> select2(SampleQueryDto query) {
        return this.selectList(Wrappers.<Sample>lambdaQuery()
                .or().eq(Objects.nonNull(query.getId()), Sample::getId, query.getId())
                .or().like(Objects.nonNull(query.getName()), Sample::getName, query.getName())
                .or().between(Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate()), Sample::getCreateTime, query.getStartDate(), query.getEndDate())
        );
    }

    default List<Sample> select3(SampleQueryDto query) {
        return this.selectList(Wrappers.<Sample>lambdaQuery()
                .between(Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate()), Sample::getCreateTime, query.getStartDate(), query.getEndDate())
                .and(Objects.nonNull(query.getId()) || Objects.nonNull(query.getName()),
                        wrapper -> wrapper.eq(Objects.nonNull(query.getId()), Sample::getId, query.getId())
                                .or().like(Objects.nonNull(query.getName()), Sample::getName, query.getName())
                )
        );
    }
}

四、【Mybatis-Flex】QueryWrapper方式

定义dao接口，使用Mybatis-Flex QueryWrapper 动态构建查询条件：

import com.mybatisflex.core.BaseMapper;
import com.mybatisflex.core.query.QueryWrapper

public interface SampleMapper extends BaseMapper<Sample> {


    default List<Sample> select1(SampleQueryDto query) {
        return this.selectListByQuery(QueryWrapper.create()
                .eq(Sample::getId, query.getId(), Objects.nonNull(query.getId()))
                .like(Sample::getName, query.getName(), Objects.nonNull(query.getName()))
                .between(Sample::getCreateTime, query.getStartDate(), query.getEndDate(), Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate()))
        );
    }

    default List<Sample> select2(SampleQueryDto query) {
        return this.selectListByQuery(QueryWrapper.create()
                .or(Sample::getId).eq(query.getId(), Objects.nonNull(query.getId()))
                .or(Sample::getName).like(query.getName(), Objects.nonNull(query.getName()))
                .or(Sample::getCreateTime).between(query.getStartDate(), query.getEndDate(), Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate()))
        );
    }

    default List<Sample> select3(SampleQueryDto query) {
        return this.selectListByQuery(QueryWrapper.create()
                .between(Sample::getCreateTime, query.getStartDate(), query.getEndDate(), Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate()))
                .and(queryWrapper -> {
                    queryWrapper.eq(Sample::getId, query.getId(), Objects.nonNull(query.getId()))
                            .or(Sample::getName).like(query.getName(), Objects.nonNull(query.getName()));
                }, Objects.nonNull(query.getId()) || Objects.nonNull(query.getName())));
    }
}

五、【Mybatis-Flex】QueryWrapper & APT方式

定义dao接口，使用Mybatis-Flex QueryWrapper 和基于APT生成的查询辅助类动态构建查询条件：

import com.mybatisflex.core.BaseMapper;
import com.mybatisflex.core.query.QueryWrapper;
import static com.luo.po.table.SampleTableDef.SAMPLE;

public interface SampleMapper extends BaseMapper<Sample> {

    default List<Sample> select1(SampleQueryDto query) {
        return this.selectListByQuery(QueryWrapper.create()
                .where(SAMPLE.ID.eq(query.getId(), Objects.nonNull(query.getId())))
                .and(SAMPLE.NAME.like(query.getName(), Objects.nonNull(query.getName())))
                .and(SAMPLE.CREATE_TIME.between(query.getStartDate(), query.getEndDate(), Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())))
        );
    }

    default List<Sample> select2(SampleQueryDto query) {
        return this.selectListByQuery(QueryWrapper.create()
                .where(SAMPLE.ID.eq(query.getId(), Objects.nonNull(query.getId())))
                .or(SAMPLE.NAME.like(query.getName(), Objects.nonNull(query.getName())))
                .or(SAMPLE.CREATE_TIME.between(query.getStartDate(), query.getEndDate(), Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())))
        );
    }

    default List<Sample> select3(SampleQueryDto query) {
        return this.selectListByQuery(QueryWrapper.create()
                .where(SAMPLE.CREATE_TIME.between(query.getStartDate(), query.getEndDate(), Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())))
                .and(SAMPLE.ID.eq(query.getId(), Objects.nonNull(query.getId()))
                        .or(SAMPLE.NAME.like(query.getName(), Objects.nonNull(query.getName()))))
        );
    }
}

六、【Spring Data JPA】Specification方式

定义仓库接口，使用Spring Data JPA Specification构建查询条件：

import org.springframework.data.jpa.domain.Specification;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.querydsl.QuerydslPredicateExecutor;
import org.springframework.util.CollectionUtils;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

/**
 * 示例仓库（Specification）
 *
 * @author luohq
 * @date 2024-11-25 13:01
 * @link https://docs.spring.io/spring-data/jpa/reference/jpa/specifications.html
 */
public interface SampleRepo1 extends JpaRepository<Sample, String>, JpaSpecificationExecutor<Sample>, QuerydslPredicateExecutor<Sample> {

    default List<Sample> select1(SampleQuery query) {
        //构建查询条件
        Specification<Sample> specification = new Specification<>() {
            @Override
            public Predicate toPredicate(Root<Sample> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>(3);
                if (Objects.nonNull(query.getId())) {
                    predicates.add(cb.equal(root.get("id"), query.getId()));
                }
                if (Objects.nonNull(query.getName())) {
                    predicates.add(cb.like(root.get("name"), "%" + query.getName() + "%"));
                }
                if (Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())) {
                    predicates.add(cb.between(root.get("createTime"), query.getStartDate(), query.getEndDate()));
                }
                return cb.and(predicates.toArray(Predicate[]::new));
            }
        };
        //执行查询
        return this.findAll(specification);
    }

    default List<Sample> select2(SampleQuery query) {
        //构建查询条件
        Specification<Sample> specification = new Specification<>() {
            @Override
            public Predicate toPredicate(Root<Sample> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>(3);
                if (Objects.nonNull(query.getId())) {
                    predicates.add(cb.equal(root.get("id"), query.getId()));
                }
                if (Objects.nonNull(query.getName())) {
                    predicates.add(cb.like(root.get("name"), "%" + query.getName() + "%"));
                }
                if (Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())) {
                    predicates.add(cb.between(root.get("createTime"), query.getStartDate(), query.getEndDate()));
                }
                if (CollectionUtils.isEmpty(predicates)) {
                    //默认添加一个成立条件，避免多个or条件为空时拼接0=1
                    predicates.add(cb.equal(cb.literal(1), 1));
                }
                return cb.or(predicates.toArray(Predicate[]::new));
            }
        };
        //执行查询
        return this.findAll(specification);
    }

    default List<Sample> select3(SampleQuery query) {
        //构建查询条件
        Specification<Sample> specification = new Specification<>() {
            @Override
            public Predicate toPredicate(Root<Sample> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>(2);
                if (Objects.nonNull(query.getId())) {
                    predicates.add(cb.equal(root.get("id"), query.getId()));
                }
                if (Objects.nonNull(query.getName())) {
                    predicates.add(cb.like(root.get("name"), "%" + query.getName() + "%"));
                }
                if (CollectionUtils.isEmpty(predicates)) {
                    //默认添加一个成立条件，避免多个or条件为空时拼接0=1
                    predicates.add(cb.equal(cb.literal(1), 1));
                }
                Predicate group1 = cb.or(predicates.toArray(Predicate[]::new));


                predicates = new ArrayList<>(1);
                if (Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())) {
                    predicates.add(cb.between(root.get("createTime"), query.getStartDate(), query.getEndDate()));
                }
                Predicate group2 = cb.and(predicates.toArray(Predicate[]::new));

                return cb.and(group1, group2);
            }
        };
        //执行查询
        return this.findAll(specification);
    }
}

七、【Spring Data JPA】Specification & MetaModel方式

定义仓库接口，使用Spring Data JPA Specification 和动态生成的JPA元模型构建查询条件：

import com.luo.po.Sample;
import com.luo.po.Sample_;
import com.luo.query.SampleQuery;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.querydsl.QuerydslPredicateExecutor;
import org.springframework.util.CollectionUtils;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

/**
 * 示例仓库（Specification、MetaModel）
 *
 * @author luohq
 * @date 2024-11-25 13:01
 * @link https://docs.spring.io/spring-data/jpa/reference/jpa/specifications.html
 * @link https://docs.jboss.org/hibernate/jpamodelgen/1.3/reference/en-US/html_single/
 */
public interface SampleRepo2 extends JpaRepository<Sample, String>, JpaSpecificationExecutor<Sample>, QuerydslPredicateExecutor<Sample> {

    default List<Sample> select1(SampleQuery query) {
        //构建查询条件
        Specification<Sample> specification = new Specification<>() {
            @Override
            public Predicate toPredicate(Root<Sample> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>(3);
                if (Objects.nonNull(query.getId())) {
                    predicates.add(cb.equal(root.get(Sample_.ID), query.getId()));
                }
                if (Objects.nonNull(query.getName())) {
                    predicates.add(cb.like(root.get(Sample_.NAME), "%" + query.getName() + "%"));
                }
                if (Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())) {
                    predicates.add(cb.between(root.get(Sample_.CREATE_TIME), query.getStartDate(), query.getEndDate()));
                }
                return cb.and(predicates.toArray(Predicate[]::new));
            }
        };
        //执行查询
        return this.findAll(specification);
    }

    default List<Sample> select2(SampleQuery query) {
        //构建查询条件
        Specification<Sample> specification = new Specification<>() {
            @Override
            public Predicate toPredicate(Root<Sample> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>(3);
                if (Objects.nonNull(query.getId())) {
                    predicates.add(cb.equal(root.get(Sample_.ID), query.getId()));
                }
                if (Objects.nonNull(query.getName())) {
                    predicates.add(cb.like(root.get(Sample_.NAME), "%" + query.getName() + "%"));
                }
                if (Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())) {
                    predicates.add(cb.between(root.get(Sample_.CREATE_TIME), query.getStartDate(), query.getEndDate()));
                }
                if (CollectionUtils.isEmpty(predicates)) {
                    //默认添加一个成立条件，避免多个or条件为空时拼接0=1
                    predicates.add(cb.equal(cb.literal(1), 1));
                }
                return cb.or(predicates.toArray(Predicate[]::new));
            }
        };
        //执行查询
        return this.findAll(specification);
    }

    default List<Sample> select3(SampleQuery query) {
        //构建查询条件
        Specification<Sample> specification = new Specification<>() {
            @Override
            public Predicate toPredicate(Root<Sample> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>(2);
                if (Objects.nonNull(query.getId())) {
                    predicates.add(cb.equal(root.get(Sample_.ID), query.getId()));
                }
                if (Objects.nonNull(query.getName())) {
                    predicates.add(cb.like(root.get(Sample_.NAME), "%" + query.getName() + "%"));
                }
                if (CollectionUtils.isEmpty(predicates)) {
                    //默认添加一个成立条件，避免多个or条件为空时拼接0=1
                    predicates.add(cb.equal(cb.literal(1), 1));
                }
                Predicate group1 = cb.or(predicates.toArray(Predicate[]::new));


                predicates = new ArrayList<>(1);
                if (Objects.nonNull(query.getStartDate()) && Objects.nonNull(query.getEndDate())) {
                    predicates.add(cb.between(root.get(Sample_.CREATE_TIME), query.getStartDate(), query.getEndDate()));
                }
                Predicate group2 = cb.and(predicates.toArray(Predicate[]::new));

                return cb.and(group1, group2);
            }
        };
        //执行查询
        return this.findAll(specification);
    }
}

八、【Spring Data JPA】QueryDsl方式

定义仓库接口，使用 Spring Data JPA 和 QueryDsl 构建查询条件：

import com.luo.po.Sample;
import static com.luo.po.QSample.sample;
import com.luo.query.SampleQuery;
import com.querydsl.core.types.Predicate;
import com.querydsl.core.types.dsl.BooleanExpression;
import com.querydsl.core.types.dsl.Expressions;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.querydsl.QuerydslPredicateExecutor;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

/**
 * 示例仓库（Specification、QueryDsl）
 *
 * @author luohq
 * @date 2024-11-25 13:01
 * @link https://docs.spring.io/spring-data/jpa/reference/jpa/specifications.html
 * @link https://docs.spring.io/spring-data/jpa/reference/repositories/core-extensions.html#core.extensions.querydsl
 */
public interface SampleRepo3 extends JpaRepository<Sample, String>, JpaSpecificationExecutor<Sample>, QuerydslPredicateExecutor<Sample> {

    default List<Sample> select1(SampleQuery query) {
        //Predicate predicate = sample.id.eq(query.getId())
        //        .and(sample.name.contains(query.getName()))
        //        .and(sample.createTime.between(query.getStartDate(), query.getEndDate()));

        //构建查询条件
        List<BooleanExpression> predicates = new ArrayList<>();
        if (query.getId() != null) {
            predicates.add(sample.id.eq(query.getId()));
        }
        if (query.getName() != null) {
            predicates.add(sample.name.contains(query.getName()));
        }
        if (query.getStartDate() != null && query.getEndDate() != null) {
            predicates.add(sample.createTime.between(query.getStartDate(), query.getEndDate()));
        }
        //避免空指针异常
        if (predicates.isEmpty()) {
            predicates.add(Expressions.asBoolean(true).isTrue());
        }
        //合并查询条件
        BooleanExpression predicate = Expressions.allOf(predicates.toArray(new BooleanExpression[predicates.size()]));

        //执行查询
        Iterable<Sample> all = this.findAll(predicate);

        return StreamSupport.stream(all.spliterator(), false)
                .collect(Collectors.toList());
    }

    default List<Sample> select2(SampleQuery query) {
        //Predicate predicate = sample.id.eq(query.getId())
        //        .or(sample.name.contains(query.getName()))
        //        .or(sample.createTime.between(query.getStartDate(), query.getEndDate()));

        //构建查询条件
        List<BooleanExpression> predicates = new ArrayList<>();
        if (query.getId() != null) {
            predicates.add(sample.id.eq(query.getId()));
        }
        if (query.getName() != null) {
            predicates.add(sample.name.contains(query.getName()));
        }
        if (query.getStartDate() != null && query.getEndDate() != null) {
            predicates.add(sample.createTime.between(query.getStartDate(), query.getEndDate()));
        }
        //避免空指针异常
        if (predicates.isEmpty()) {
            predicates.add(Expressions.asBoolean(true).isTrue());
        }
        //合并查询条件
        BooleanExpression predicate = Expressions.anyOf(predicates.toArray(new BooleanExpression[predicates.size()]));

        //执行查询
        Iterable<Sample> all = this.findAll(predicate);

        return StreamSupport.stream(all.spliterator(), false)
                .collect(Collectors.toList());

    }

    default List<Sample> select3(SampleQuery query) {
        //Predicate predicate = sample.createTime.between(query.getStartDate(), query.getEndDate())
        //        .and(sample.id.eq(query.getId())
        //                .or(sample.name.contains(query.getName()))
        //        );

        //构建查询条件 - 分组1
        List<BooleanExpression> predicates = new ArrayList<>();
        if (query.getStartDate() != null && query.getEndDate() != null) {
            predicates.add(sample.createTime.between(query.getStartDate(), query.getEndDate()));
        }
        //避免空指针异常
        if (predicates.isEmpty()) {
            predicates.add(Expressions.asBoolean(true).isTrue());
        }
        //合并查询条件
        BooleanExpression group1 = Expressions.allOf(predicates.toArray(new BooleanExpression[predicates.size()]));

        //构建查询条件 - 分组2
        predicates = new ArrayList<>();
        if (query.getId() != null) {
            predicates.add(sample.id.eq(query.getId()));
        }
        if (query.getName() != null) {
            predicates.add(sample.name.contains(query.getName()));
        }
        //避免空指针异常
        if (predicates.isEmpty()) {
            predicates.add(Expressions.asBoolean(true).isTrue());
        }
        //合并查询条件
        BooleanExpression group2 = Expressions.anyOf(predicates.toArray(new BooleanExpression[predicates.size()]));

        //合并分组条件
        Predicate predicate = Expressions.allOf(group1, group2);
        //执行查询
        Iterable<Sample> all = this.findAll(predicate);
        return StreamSupport.stream(all.spliterator(), false)
                .collect(Collectors.toList());
    }
}