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Spring Data JPA实现动态条件与范围查询

程序员文章站 2022-03-10 16:46:19
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Spring Data JPA为我们提供了Query With Example来实现动态条件查询，当查询条件为空的时候，我们不用做大量的条件判断。但是Query With Example却不支持范围查询(包括日期范围，数值范围查询)，本文通过Specification实现了既支持动态条件查询又支持范围查询的方法。

 

排版良好地址：Spring Data JPA实现动态条件与范围查询

1 实现方式

1.1 范围对象Range定义

import java.io.Serializable;


public class Range<E> implements Serializable {
    private static final long serialVersionUID = 1L;

    private String field;
    private Comparable from;
    private Comparable to;
    private Boolean includeNull;


    public Range(String field) {
        this.field = field;
    }


    public Range(String field, Comparable from, Comparable to) {
        this.field = field;
        this.from = from;
        this.to = to;
    }

    public Range(String field, Comparable from, Comparable to, Boolean includeNull) {
        this.field = field;
        this.from = from;
        this.to = to;
        this.includeNull = includeNull;
    }


    public Range(Range<E> other) {
        this.field = other.getField();
        this.from = other.getFrom();
        this.to = other.getTo();
        this.includeNull = other.getIncludeNull();
    }

    public String getField() {
        return field;
    }

    public Comparable getFrom() {
        return from;
    }


    public void setFrom(Comparable from) {
        this.from = from;
    }

    public boolean isFromSet() {
        return getFrom() != null;
    }


    public Comparable getTo() {
        return to;
    }

    public void setTo(Comparable to) {
        this.to = to;
    }

    public boolean isToSet() {
        return getTo() != null;
    }

    public void setIncludeNull(boolean includeNull) {
        this.includeNull = includeNull;
    }

    public Boolean getIncludeNull() {
        return includeNull;
    }

    public boolean isIncludeNullSet() {
        return includeNull != null;
    }

    public boolean isBetween() {
        return isFromSet() && isToSet();
    }

    public boolean isSet() {
        return isFromSet() || isToSet() || isIncludeNullSet();
    }

    public boolean isValid() {
        if (isBetween()) {
            return getFrom().compareTo(getTo()) <= 0;
        }

        return true;
    }
}

1.2 example的Specification

import org.springframework.data.domain.Example;
import org.springframework.data.jpa.convert.QueryByExamplePredicateBuilder;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.util.Assert;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;

/**
 * Created by wangyunfei on 2017/6/6.
 */
public class ByExampleSpecification<T> implements Specification<T> {
    private final Example<T> example;

    public ByExampleSpecification(Example<T> example) {

        Assert.notNull(example, "Example must not be null!");
        this.example = example;
    }


    @Override
    public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
        return QueryByExamplePredicateBuilder.getPredicate(root, cb, example);
    }
}

1.3 Range的Specification

import org.springframework.data.jpa.domain.Specification;

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

import static com.google.common.collect.Iterables.toArray;
import static com.google.common.collect.Lists.newArrayList;
import static java.lang.Boolean.FALSE;
import static java.lang.Boolean.TRUE;

/**
 * Created by wangyunfei on 2017/6/6.
 */
public class  ByRangeSpecification<T> implements Specification<T> {
    private  final  List<Range<T>> ranges;

    public  ByRangeSpecification(List<Range<T>> ranges) {
        this.ranges = ranges;
    }

    @Override
    public  Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
        List<Predicate> predicates = newArrayList();

        for (Range<T> range : ranges) {
            if (range.isSet()) {
                Predicate rangePredicate = buildRangePredicate(range, root, builder);

                if (rangePredicate != null) {
                    if (!range.isIncludeNullSet() || range.getIncludeNull() == FALSE) {
                        predicates.add(rangePredicate);
                    } else {
                        predicates.add(builder.or(rangePredicate, builder.isNull(root.get(range.getField()))));
                    }
                }

                if (TRUE == range.getIncludeNull()) {
                    predicates.add(builder.isNull(root.get(range.getField())));
                } else if (FALSE == range.getIncludeNull()) {
                    predicates.add(builder.isNotNull(root.get(range.getField())));
                }
            }
        }
        return predicates.isEmpty() ? builder.conjunction() : builder.and(toArray(predicates, Predicate.class));
    }

    private Predicate buildRangePredicate(Range<T> range, Root<T> root, CriteriaBuilder builder) {
        if (range.isBetween()) {
            return builder.between(root.get(range.getField()), range.getFrom(), range.getTo());
        } else if (range.isFromSet()) {
            return builder.greaterThanOrEqualTo(root.get(range.getField()), range.getFrom());
        } else if (range.isToSet()) {
            return builder.lessThanOrEqualTo(root.get(range.getField()), range.getTo());
        }
        return null;
    }

}

1.4 自定义Repository与实现

import org.springframework.data.domain.Example;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.NoRepositoryBean;

import java.io.Serializable;
import java.util.List;

@NoRepositoryBean
public interface WiselyRepository<E, PK extends Serializable> extends JpaRepository<E, PK> {


 Page<E> queryByExampleWithRange(Example example,List<Range<E>> ranges, Pageable pageable);

}

import org.springframework.data.domain.Example;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.data.jpa.repository.support.JpaEntityInformation;
import org.springframework.data.jpa.repository.support.SimpleJpaRepository;

import javax.persistence.EntityManager;
import java.io.Serializable;
import java.util.List;

import static org.springframework.data.jpa.domain.Specifications.where;


public class WiselyRepositoryImpl<E, PK extends Serializable> extends SimpleJpaRepository<E, PK> implements
        WiselyRepository<E, PK> {
    private final EntityManager entityManager;

    public WiselyRepositoryImpl(JpaEntityInformation entityInformation, EntityManager entityManager) {
        super(entityInformation, entityManager);
        this.entityManager = entityManager;
    }



    @Override
    public Page<E> queryByExampleWithRange(Example example, List<Range<E>> ranges, Pageable pageable) {
        Specification<E> byExample = new ByExampleSpecification<>(example);
        Specification<E> byRanges = new ByRangeSpecification<>(ranges);
        return findAll(where(byExample).and(byRanges),pageable);
    }
}

2 使用方式

2.1 开启支持

通过@EnableJpaRepositories(repositoryBaseClass = WiselyRepositoryImpl.class)开启对定义功能的支持。

2.2 示例

  • 实体类
@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Person {
    @Id
    @GeneratedValue
    private Long id;
    private String name;
    private Integer height;
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private Date birthday;
}
  • PersonRepository
public interface PersonRepository extends WiselyRepository<Person,Long> {
}
  • 测试控制器
@RestController
@RequestMapping("/people")
public class PersonController {

    @Autowired
    PersonRepository personRepository;

    @PostMapping
    public ResponseEntity<Person> save(@RequestBody Person person){
        Person p = personRepository.save(person);
        return new ResponseEntity<Person>(p, HttpStatus.CREATED);
    }


    @GetMapping
    public ResponseEntity<Page<Person>> query(Person person,
                                              @DateTimeFormat(pattern = "yyyy-MM-dd")Date startDate,
                                              @DateTimeFormat(pattern = "yyyy-MM-dd")Date endDate,
                                              Integer startHeight,
                                              Integer endHeight,
                                              Pageable pageable){
        Example<Person> personExample = Example.of(person);

        List<Range<Person>> ranges = newArrayList();
        Range<Person> birthRange = new Range<Person>("birthday",startDate,endDate);
        Range<Person> heightRange = new Range<Person>("height",startHeight,endHeight);
        ranges.add(birthRange);
        ranges.add(heightRange);

        Page<Person> page = personRepository.queryByExampleWithRange(personExample,ranges,pageable);

        return new ResponseEntity<Page<Person>>(page,HttpStatus.OK);

    }
}

源码地址：https://github.com/wiselyman/query_with_example_and_range

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