QueryDsl Web查询关于Map字段的键

Question

给定

• Spring Data JPA，Spring Data Rest，QueryDsl
• 一个Meetup实体
  • 有Map<String,String> properties田野
  • 坚持作为一个MEETUP_PROPERTY表@ElementCollection
• 一个 MeetupRepository
  • 延伸 QueryDslPredicateExecutor<Meetup>

我希望

网络查询

GET /api/meetup?properties[aKey]=aValue

仅返回具有指定键和值的属性条目的Meetups：aKey = aValue。

但是，这对我不起作用。我想念什么？

试过了

简单字段

简单的字段可以工作，例如名称和描述：

GET /api/meetup?name=whatever

收集字段像参与者一样工作：

GET /api/meetup?participants.name=whatever

但不是此Map字段。

自定义QueryDsl绑定

我尝试通过拥有存储库来定制绑定

extend QuerydslBinderCustomizer<QMeetup>

并覆盖

customize(QuerydslBindings bindings, QMeetup meetup)

方法，但是当customize()方法被点击时，lambda内部的绑定代码却没有。

编辑：了解到这是因为QuerydslBindings评估查询参数的方法不允许它与pathSpecs它内部持有的地图相匹配-里面有您的自定义绑定。

一些细节

Meetup.properties字段

@ElementCollection(fetch = FetchType.EAGER)
@CollectionTable(name = "MEETUP_PROPERTY", joinColumns = @JoinColumn(name = "MEETUP_ID"))
@MapKeyColumn(name = "KEY")
@Column(name = "VALUE", length = 2048)
private Map<String, String> properties = new HashMap<>();

定制的querydsl绑定

编辑： 见上文；事实证明，这对我的代码无济于事。

public interface MeetupRepository extends PagingAndSortingRepository<Meetup, Long>,
                                          QueryDslPredicateExecutor<Meetup>,
                                          QuerydslBinderCustomizer<QMeetup> {

    @Override
    default void customize(QuerydslBindings bindings, QMeetup meetup) {
        bindings.bind(meetup.properties).first((path, value) -> {
            BooleanBuilder builder = new BooleanBuilder();
            for (String key : value.keySet()) {
                builder.and(path.containsKey(key).and(path.get(key).eq(value.get(key))));
            }
            return builder;
        });
}

其他发现

1. QuerydslPredicateBuilder.getPredicate()要求QuerydslBindings.getPropertyPath()尝试2种方法从中返回路径，以便它可以使谓词QuerydslAwareRootResourceInformationHandlerMethodArgumentResolver.postProcess()可用。
   • 1是查看自定义绑定。我在那里看不到任何表示地图查询的方法
   • 2是默认使用Spring的bean路径。那里同样表达问题。您如何表达地图？因此似乎无法QuerydslPredicateBuilder.getPredicate()自动创建谓词。很好-如果可以加入，我可以手动完成QuerydslAwareRootResourceInformationHandlerMethodArgumentResolver.postProcess()

如何覆盖该类或替换Bean？它被实例化，并在RepositoryRestMvcConfiguration.repoRequestArgumentResolver()bean声明中作为bean返回。

1. 我 可以 通过声明自己的repoRequestArgumentResolverbean 来 覆盖该bean ，但是不会被使用。
   • 它被RepositoryRestMvcConfigurations 覆盖。我无法通过设置它或来 强制 它。@Primary``@Ordered(HIGHEST_PRECEDENCE)
   • 我 可以 通过显式的组件扫描 来 强制执行此操作RepositoryRestMvcConfiguration.class，但这也会弄乱Spring Boot的自动配置，因为它会导致 RepositoryRestMvcConfiguration's在运行任何自动配置之前处理Bean声明。除其他外，这导致响应被杰克逊以不需要的方式序列化。

问题

好吧-好像我所期望的支持不存在。

所以问题就变成了： 我该 如何 正确地覆盖repoRequestArgumentResolverbean？

BTW-
QuerydslAwareRootResourceInformationHandlerMethodArgumentResolver尴尬的非公开。：/

Answer 1

更换豆

实施ApplicationContextAware

这就是我在应用html" target="_blank">程序上下文中替换bean的方式。

感觉有点。我希望听到一种更好的方法。

@Configuration
public class CustomQuerydslHandlerMethodArgumentResolverConfig implements ApplicationContextAware {

    /**
     * This class is originally the class that instantiated QuerydslAwareRootResourceInformationHandlerMethodArgumentResolver and placed it into the Spring Application Context
     * as a {@link RootResourceInformationHandlerMethodArgumentResolver} by the name of 'repoRequestArgumentResolver'.<br/>
     * By injecting this bean, we can let {@link #meetupApiRepoRequestArgumentResolver} delegate as much as possible to the original code in that bean.
     */
    private final RepositoryRestMvcConfiguration repositoryRestMvcConfiguration;

    @Autowired
    public CustomQuerydslHandlerMethodArgumentResolverConfig(RepositoryRestMvcConfiguration repositoryRestMvcConfiguration) {
        this.repositoryRestMvcConfiguration = repositoryRestMvcConfiguration;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) ((GenericApplicationContext) applicationContext).getBeanFactory();
        beanFactory.destroySingleton(REPO_REQUEST_ARGUMENT_RESOLVER_BEAN_NAME);
        beanFactory.registerSingleton(REPO_REQUEST_ARGUMENT_RESOLVER_BEAN_NAME,
                                      meetupApiRepoRequestArgumentResolver(applicationContext, repositoryRestMvcConfiguration));
    }

    /**
     * This code is mostly copied from {@link RepositoryRestMvcConfiguration#repoRequestArgumentResolver()}, except the if clause checking if the QueryDsl library is
     * present has been removed, since we're counting on it anyway.<br/>
     * That means that if that code changes in the future, we're going to need to alter this code... :/
     */
    @Bean
    public RootResourceInformationHandlerMethodArgumentResolver meetupApiRepoRequestArgumentResolver(ApplicationContext applicationContext,
                                                                                                     RepositoryRestMvcConfiguration repositoryRestMvcConfiguration) {
        QuerydslBindingsFactory factory = applicationContext.getBean(QuerydslBindingsFactory.class);
        QuerydslPredicateBuilder predicateBuilder = new QuerydslPredicateBuilder(repositoryRestMvcConfiguration.defaultConversionService(),
                                                                                 factory.getEntityPathResolver());

        return new CustomQuerydslHandlerMethodArgumentResolver(repositoryRestMvcConfiguration.repositories(),
                                                               repositoryRestMvcConfiguration.repositoryInvokerFactory(repositoryRestMvcConfiguration.defaultConversionService()),
                                                               repositoryRestMvcConfiguration.resourceMetadataHandlerMethodArgumentResolver(),
                                                               predicateBuilder, factory);
    }
}

从http参数创建Map-searching谓词

扩展RootResourceInformationHandlerMethodArgumentResolver

这些是基于http查询参数创建我自己的Map-search谓词的代码段。再次-很想知道更好的方法。

该postProcess方法调用：

        predicate = addCustomMapPredicates(parameterMap, predicate, domainType).getValue();

就 在将predicate引用传递到QuerydslRepositoryInvokerAdapter构造函数并返回之前。

这是该addCustomMapPredicates方法：

    private BooleanBuilder addCustomMapPredicates(MultiValueMap<String, String> parameters, Predicate predicate, Class<?> domainType) {
        BooleanBuilder booleanBuilder = new BooleanBuilder();
        parameters.keySet()
                  .stream()
                  .filter(s -> s.contains("[") && matches(s) && s.endsWith("]"))
                  .collect(Collectors.toList())
                  .forEach(paramKey -> {
                      String property = paramKey.substring(0, paramKey.indexOf("["));
                      if (ReflectionUtils.findField(domainType, property) == null) {
                          LOGGER.warn("Skipping predicate matching on [%s]. It is not a known field on domainType %s", property, domainType.getName());
                          return;
                      }
                      String key = paramKey.substring(paramKey.indexOf("[") + 1, paramKey.indexOf("]"));
                      parameters.get(paramKey).forEach(value -> {
                          if (!StringUtils.hasLength(value)) {
                              booleanBuilder.or(matchesProperty(key, null));
                          } else {
                              booleanBuilder.or(matchesProperty(key, value));
                          }
                      });
                  });
        return booleanBuilder.and(predicate);
    }

    static boolean matches(String key) {
        return PATTERN.matcher(key).matches();
    }

和模式：

    /**
     * disallow a . or ] from preceding a [
     */
    private static final Pattern PATTERN = Pattern.compile(".*[^.]\\[.*[^\\[]");