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我有一個名爲'標記'的屬性值列表。我試圖過濾一種實體谷歌應用程序引擎查詢與字符串列表
這是我試過的。
List<String> tokens = getTokensFrom(invitations);
PersistenceManager pm = this.dataStoreService.getObjectDBConnection();
Query query = pm.newQuery(Invitations.class);
query.setFilter("tokens.contains(token)");
query.declareVariables(List.class.getName() + " tokens");
List<Invitations> invites = (List<Invitations>) query.execute(tokens);
但我收到以下錯誤消息。
Problem with query <SELECT FROM com.mypackage.shared.domainobjects.Invitations WHERE tokens.contains(token) VARIABLES java.util.List tokens>: Unsupported method <contains> while parsing expression: InvokeExpression{[VariableExpression{tokens}].contains(PrimaryExpression{token})}
com.google.appengine.datanucleus.query.DatastoreQuery$UnsupportedDatastoreFeatureException: Problem with query <SELECT FROM com.testbudha.shared.domainobjects.PublishedExam WHERE tokens.contains(token) VARIABLES java.util.Collection tokens>: Unsupported method <contains> while parsing expression: InvokeExpression{[VariableExpression{tokens}].contains(PrimaryExpression{token})}
at com.google.appengine.datanucleus.query.DatastoreQuery.newUnsupportedQueryMethodException(DatastoreQuery.java:993)
at com.google.appengine.datanucleus.query.DatastoreQuery.handleContainsOperation(DatastoreQuery.java:971)
at com.google.appengine.datanucleus.query.DatastoreQuery.addExpression(DatastoreQuery.java:830)
at com.google.appengine.datanucleus.query.DatastoreQuery.addFilters(DatastoreQuery.java:739)
at com.google.appengine.datanucleus.query.DatastoreQuery.compile(DatastoreQuery.java:248)
at com.google.appengine.datanucleus.query.JDOQLQuery.performExecute(JDOQLQuery.java:158)
at org.datanucleus.store.query.Query.executeQuery(Query.java:1789)
at org.datanucleus.store.query.Query.executeWithArray(Query.java:1666)
at org.datanucleus.api.jdo.JDOQuery.execute(JDOQuery.java:243)
我以前也有類似的問題，但它的作品，因爲過濾條件是倒過來即this.token.contains（標記），其中「令牌」是實體的一部分，是字符串類型的List 。但我不知道爲什麼這不起作用。有人可以幫幫我嗎？