java - 为 JPA 和 Spring boot 实现搜索功能

Question

我正在尝试为数据库表实现正确的搜索功能。我尝试了这种方法：

控制器：

    @GetMapping
    public Page<TransactionDTO> find(TransactionFilterDTO filter, Pageable page) {
        return searchRepository
                .findTransactionsByFilter(mapper.toFilter(filter), page)
                .map(mapper::toDTO);
    }

归档 DTO：

public class TransactionFilterDTO {

    private String name;

    private Integer id;

    @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME)
    private LocalDateTime from;

    @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME)
    private LocalDateTime to;
    ... // getters and setter
}

搜索实现：

@Repository
public class TransactionSearchRepositoryImpl implements TransactionSearchRepository {

    @Autowired
    private TransactionRepository transactionRepository;

    @Autowired
    private TransactionSpecification specification;

    @Override
    public Page<Transaction> findTransactionsByFilter(TransactionFilter filter, @Nullable Pageable page) {


        List<Transaction> transactions = transactionRepository
                .findAll(specification.getFilter(filter));

        int totalCount = transactions.size();

        if(page != null) {
           transactions = transactions
                   .stream()
                   .skip(page.getOffset())
                   .limit(page.getPageSize())
                   .collect(Collectors.toList());
        }

        return new PageImpl<>(transactions, page, totalCount);
    }
}

存储库：

public interface TransactionSearchRepository {

    Page<Transaction> findTransactionsByFilter(TransactionFilter filter, Pageable page);
}

有没有更好的方法来实现搜索功能？在我看来，这个解决方案非常难看。

标签： javaspringspring-bootspring-data-jpa

Answer 1

我可以推荐几种方法来解决这样的任务：

1）简单但不灵活：只需根据您的过滤器属性（name, from, to）在控制器中使用请求参数并在您的存储库中准备相应的查询，例如：

控制器：

@GetMapping("/q")
public List<ResponseDto> getAllByQuery(
    @RequestParam(value = "name", required = false) String name,
    @RequestParam(value = "from", required = false) @DateTimeFormat(iso = ISO.DATE) LocalDate from,
    @RequestParam(value = "to", required = false) @DateTimeFormat(iso = ISO.DATE) LocalDate to,
    Pageable pageable
) {
    return service.getByQuery(name, from, to, pageable);
}

服务：

public Page<ResponseDto> getByQuery(String name, LocalDate from, LocalDate to, Pageable pageable) {
    return repo.getByQuery(name, from, to, pageable).map(mapper::toResponseDto);
}

存储库：

@Query("select m from MyEntity m where " +
       "(?1 is null or upper(m.name) like concat('%', upper(?1), '%')) " +
       "and (?2 is null or m.createdAt >= ?2) " +
       "and (?3 is null or m.createdAt <= ?3)")
Page<MyEntity> getByQuery(String name, final LocalDate from, final LocalDate to, final Pageable pageable);

然后执行一个请求：

GET http://localhost:8080/q?name=john&from=2019-04-19&to=2019-04-19

2）使用QueryDsl。您应该将它添加到您的项目中（您可以在此处QuerydslPredicateExecutor找到详细信息），从和扩展您的存储库，并QuerydslBinderCustomizer为其添加一些“调整”：

public interface MyEntityRepo extends JpaRepository<MyEntity, Integer>, QuerydslPredicateExecutor<MyEntity>, QuerydslBinderCustomizer<QMyEntity> {
    @Override
    default void customize(@NonNull QuerydslBindings bindings, @NonNull QMyEntity entity) {

        // Make case-insensitive 'like' filter for all string properties
        bindings.bind(String.class).first((SingleValueBinding<StringPath, String>) StringExpression::containsIgnoreCase);

        // Add 'between' and 'greater or equal' filter date property
        bindings.bind(entity.createdAt).all((path, value) -> {
            Iterator<? extends LocalDate> it = value.iterator();
            LocalDate from = it.next();
            if (value.size() >= 2) {
                LocalDate to = it.next();
                return Optional.of(path.between(from, to)); // between
            } else {
                return Optional.of(path.goe(from)); // greater than or equal
            }
        });
    }

添加服务方法：

public Page<ResponseDto> getAllByQueryDsl(Predicate predicate, Pageable pageable) {
    return repo.findAll(predicate, pageable).map(mapper::toResponseDto);
}

添加控制器方法：

@GetMapping("/query-dsl")
public Page<ResponseDto> getAllByQueryDsl(
        @QuerydslPredicate(root = MyEntity.class, bindings = MyEntityRepo.class) Predicate predicate,
        Pageable pageable
) {
    return service.getAllByQueryDsl(predicate, pageable);
}

@DateTimeFormat并为您的实体的“日期”属性添加注释：

@Entity
public class MyEntity {
    // ...
    @DateTimeFormat(iso = ISO.DATE) private LocalDate createdAt;
}

然后你可以执行这样的请求：

GET http://localhost:8080/query-dsl?name=john&createdAt=2019-04-15&createdAt=2019-04-19

其中第一个日期是 'from' 参数，第二个日期是 'to' 参数。如果您只使用一个日期 - 它将是“来自”参数（大于或等于）。

3) 使用规范-arg-resolver库。将其添加到您的项目中（请参阅说明：1和2），然后从以下位置扩展您的存储库JpaSpecificationExecutor：

public interface MyEntityRepo extends JpaRepository<MyEntity, Integer>, JpaSpecificationExecutor<MyEntity> {}

将这样的方法添加到您的控制器：

@GetMapping("/specification")
public Page<ResponseDto> getAllBySpecification(
        @And({
                @Spec(path = "name", spec = LikeIgnoreCase.class),
                @Spec(path = "createdAt", params = "from", spec = GreaterThanOrEqual.class),
                @Spec(path = "createdAt", params = "to", spec = LessThanOrEqual.class)
        }) Specification<MyEntity> specification,
        Pageable pageable
) {
    return service.getAllBySpecification(specification, pageable);
}

更新您的服务：

public Page<ResponseDto> getAllBySpecification(final Specification<MyEntity> specification, final Pageable pageable) {
    return repo.findAll(specification, pageable).map(mapper::toResponseDto);
}

然后请求您的数据：

GET http://localhost:8080/specification?name=john&from=2019-04-10&to=2019-04-19

4）手动构建规范：

创建一个过滤器类：

@Data
public class MyFilter implements Specification<MyEntity> {
    private String name;
    @DateTimeFormat(iso = ISO.DATE) private LocalDate from;
    @DateTimeFormat(iso = ISO.DATE) private LocalDate to;

    @Override
    public Predicate toPredicate(Root<MyEntity> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
        List<Predicate> predicates = new ArrayList<>();
        if (name != null) predicates.add(builder.like(builder.upper(root.get("name")), "%" + name.toUpperCase() + "%"));
        if (from != null) predicates.add(builder.greaterThanOrEqualTo(root.get("createdAt"), from));
        if (to != null) predicates.add(builder.lessThanOrEqualTo(root.get("createdAt"), to));
        return builder.and(predicates.toArray(new Predicate[0]));
    }
}

创建控制器方法：

@GetMapping("/filter")
public Page<ResponseDto> getAllByMyFilter(MyFilter filter, Pageable pageable) {
    return service.getAllBySpecification(filter, pageable);
}

然后运行请求：

GET http://localhost:8080/filter?name=john&from=2019-04-10&to=2019-04-19