如何在 Spring 项目中使用 ElasticSearch 的 NativeSearchQueryBuilder return 单个对象？

Question

我正在使用 NativeSearchQueryBuilder 来形成如下查询：

 String[] includeFields = new String[]{"idDl", "clientName"};
 String[] excludeFields = new String[]{"Address"};
 Query searchQuery = new NativeSearchQueryBuilder()
                .withQuery(matchQuery("idDl", idDl))
                .withSourceFilter(new FetchSourceFilter(includeFields, excludeFields))
                 .build();
return elasticsearchRestTemplate.queryForObject((StringQuery) searchQuery, User.class);

我想 return 没有特定字段的单个对象，这是异常的堆栈跟踪：

java.lang.ClassCastException: org.springframework.data.elasticsearch.core.query.NativeSearchQuery cannot be cast to org.springframework.data.elasticsearch.core.query.StringQuery
at com.user.services.UserQueryServiceImpl.getUserById(UserQueryServiceImpl.java:37) ~[classes/:na]
at com.User.controllers.UserController.getFilteredUserById(UserController.java:100) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_231]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_231]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_231]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_231]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]

Answer 1

首先 queryForObject 已弃用，您应该使用 searchOne()。至于你的错误：

您创建一个 NativeSearchQuery，将其赋值给类型为 Query 的变量 searchQuery；没关系。但是为什么要尝试将其转换为 StringQuery?

NativeSearchQuery 和 StringQuery 都实现了 Query，因此只需传递您的查询实例：

return elasticsearchRestTemplate.queryForObject(searchQuery, User.class)

编辑 Spring Data Elasticsearch 3.2.x:

你应该使用

<T> List<T> queryForList(SearchQuery query, Class<T> clazz);

在那个版本中仍然有 NativeSearchQuery 实现的 SearchQuery 接口。从返回的列表中，检查它是否包含任何元素，然后使用第一个。

如何在 Spring 项目中使用 ElasticSearch 的 NativeSearchQueryBuilder return 单个对象？

How to return single object using NativeSearchQueryBuilder of ElasticSearch in Spring Project?

spring-mvc

elasticsearch

spring-data

spring-boot

spring-data-elasticsearch