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我试图从数据库中获取条目,需要按流派对其进行过滤:Google App Engine Java数据存储查询 - 限制结果?
<%@ page import="com.google.appengine.api.datastore.Query.Filter"%>
<%@ page import="com.google.appengine.api.datastore.Query.FilterPredicate"%>
<%@ page import="com.google.appengine.api.datastore.Query.FilterOperator"%>
<%@ page import="com.google.appengine.api.datastore.*"%>
<%@ page import="com.google.appengine.api.datastore.Query.*"%>
Query confQuery = new Query("Track");
Query.Filter topicFilter = new FilterPredicate("genre",
FilterOperator.EQUAL, genre);
confQuery.setFilter(topicFilter);
confQuery.addSort("lastplayed", SortDirection.ASCENDING);
PreparedQuery results = datastore.prepare(confQuery);
这将始终与给定类型返回的所有条目。我怎样才能限制这个10项?
FetchOptions.Builder.withLimit(10) – 4ndro1d