Question

我想用几个子条件实现搜索功能。我尝试过：

    @GetMapping("find")
    public Page<PaymentTransactionsDTO> getAllBySpecification(
            @And({
                    @Spec(path = "name", spec = LikeIgnoreCase.class),
                    @Spec(path = "unique_id", spec = LikeIgnoreCase.class),
                    @Spec(path = "createdAt", params = "from", spec = GreaterThanOrEqual.class),
                    @Spec(path = "createdAt", params = "to", spec = LessThanOrEqual.class)
            }) Specification<PaymentTransactions> specification,
            Pageable pageable
    ) {        
        return transactionService.getAllBySpecification(specification, pageable));       
    }

存储库：

      @Override
      public Page<PaymentTransactions> getAllBySpecification(final Specification<PaymentTransactions> specification, final Pageable pageable) {
          return dao.findAll(specification, pageable);
      }

当前此请求正在运行：

GET /api/transactions/find?unique_id=22&page=0&size=10

但是我也想实现这些附加的搜索条件，不仅要发送unique_id的基本搜索：

start with 
=
end with 
contains

使用https://github.com/tkaczmarzyk/specification-arg-resolver是否可以发送其他子条件？总的来说，我找不到解决方案，发送这些值的最佳做法是什么？

Answer 1

如果您要创建非常特殊的过滤器，我相信您应该从发明搜索界面开始。例如这样的

GET /models?name=eq(john smith)&createdAt=between(2019-01-01,2019-01-31)
GET /models?name=like(sm)&createdAt=from(2019-01-01)
GET /models?name=sw(john)&createdAt=to(2019-01-31)

之后，您将可以尝试实现它。

IMO解决此类任务的最佳方法是使用Spring Data JPA Specifications（和JPA Criteria API）。例如：

1）让我们创建一个Filter类，为我们的实体Specification实现Model：

@Value
public class ModelFilter implements Specification<Model> {

    private String name;
    private String createdAt;

    @Override
    public Predicate toPredicate(Root<Model> root, CriteriaQuery<?> query, CriteriaBuilder builder) {

        List<Predicate> predicates = new ArrayList<>();

        // Prepare predicates and fill the list with them...

        return builder.and(predicates.toArray(new Predicate[0]));
    }
}

2）然后创建一个控制器方法：

@GetMapping
public List<Model> getAllByFilter(ModelFilter filter) {
    return repo.findAll(filter); 
}

剩下要做的就是准备我们的谓词））

为此，我们可以先创建一个方便的“谓词生成器”界面：

@FunctionalInterface
interface PredicateBuilder<T> {

    Optional<Predicate> get(String fieldName, String value, Root<T> root, CriteriaBuilder builder);

    static Matcher getMatcher(String op, String value) {
        return getMatcher(op, value, "(.+)");
    }

    static Matcher getMatcher(String op, String value, String pattern) {
        return Pattern.compile(op + "\\(" + pattern + "\\)").matcher(value);
    }
}

然后尝试做我们的谓词：

等于

PredicateBuilder<Model> eq = (fieldName, value, root, cb) -> {
    Matcher m = getMatcher("eq", value);
    if (m.matches()) {
        return Optional.of(cb.equal(cb.upper(root.get(fieldName)), m.group(1).toUpperCase()));
    } else {
        return Optional.empty();
    }
};

喜欢

PredicateBuilder<Model> like = (fn, value, root, cb) -> {
    Matcher m = getMatcher("like", value);
    if (m.matches()) {
        return Optional.of(cb.like(cb.upper(root.get(fn)), "%" + m.group(1).toUpperCase() + "%"));
    } else {
        return Optional.empty();
    }
};

以开始

PredicateBuilder<Model> sw = (fn, value, root, cb) -> {
    Matcher m = getMatcher("sw", value);
    if (m.matches()) {
        return Optional.of(cb.like(cb.upper(root.get(fn)), m.group(1).toUpperCase() + "%"));
    } else {
        return Optional.empty();
    }
};

之间

PredicateBuilder<Model> between = (fn, value, root, cb) -> {
    Matcher m = getMatcher("between", value, "(.+)\\s*,\\s*(.+)");
    if (m.matches()) {
        LocalDate from = LocalDate.parse(m.group(1));
        LocalDate to = LocalDate.parse(m.group(2));
        return Optional.of(cb.between(root.get(fn), from, to));
    } else {
        return Optional.empty();
    }
};

来自

PredicateBuilder<Model> from = (fn, value, root, cb) -> {
    Matcher m = getMatcher("from", value);
    if (m.matches()) {
        LocalDate from = LocalDate.parse(m.group(1));
        return Optional.of(cb.greaterThanOrEqualTo(root.get(fn), from));
    } else {
        return Optional.empty();
    }
};

至

PredicateBuilder<Model> to = (fn, value, root, cb) -> {
    Matcher m = getMatcher("to", value);
    if (m.matches()) {
        LocalDate to = LocalDate.parse(m.group(1));
        return Optional.of(cb.lessThanOrEqualTo(root.get(fn), to));
    } else {
        return Optional.empty();
    }
};

仅完成Filter类就可以了：

@Value
public class ModelFilter implements Specification<Model> {

    private String name;
    private String createdAt;

    PredicateBuilder<Model> eq = ... ;
    PredicateBuilder<Model> like = ... ;
    PredicateBuilder<Model> sw = ... ;
    PredicateBuilder<Model> between = ... ;
    PredicateBuilder<Model> from = ... ;
    PredicateBuilder<Model> to = ... ;

    @Override
    public Predicate toPredicate(Root<Model> root, CriteriaQuery<?> query, CriteriaBuilder builder) {

        List<Predicate> predicates = new ArrayList<>();

        if (name != null) {
            eq.get("name", name, root, builder).ifPresent(predicates::add);
            like.get("name", name, root, builder).ifPresent(predicates::add);
            sw.get("name", name, root, builder).ifPresent(predicates::add);
        }

        if (createdAt != null) {
            between.get("createdAt", createdAt, root, builder).ifPresent(predicates::add);
            from.get("createdAt", createdAt, root, builder).ifPresent(predicates::add);
            to.get("createdAt", createdAt, root, builder).ifPresent(predicates::add);
        }

        return builder.and(predicates.toArray(new Predicate[0]));
    }
}

当然，这只是实现的一个示例。您可以创建自己的规范和谓词实现。这里的主要内容是：

出现您的搜索界面
制定“过滤器”规范
准备所有需要的谓词
在控制器方法中使用过滤器规范

使用条件实施搜索过滤器

1 个答案: