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我有以下java代码片段,演示了这个问题。我收到的错误也包含在下面。 它正确地拉正确的设置,但我无法打印。 我正在使用org.neo4j.graphdb.Node节点。这是错误的课程吗? 如果不是,我如何从ExecutionEngine获取结果movieid,avgrating和movie_title?如何从ExecutionResult中分别提取结果?
Java代码的
GraphDatabaseService db = new GraphDatabaseFactory().newEmbeddedDatabase(DB_PATH);
ExecutionEngine engine = new ExecutionEngine(db);
String cypherQuery = "MATCH (n)-[r:RATES]->(m) \n"
+ "RETURN m.movieid as movieid, avg(toFloat(r.rating)) as avgrating, m.title as movie_title \n"
+ "ORDER BY avgrating DESC \n"
+ "LIMIT 20;";
ExecutionResult result = engine.execute(cypher);
for (Map<String, Object> row : result) {
Node x = (Node) row.get("movie_title");
for (String prop : x.getPropertyKeys()) {
System.out.println(prop + ": " + x.getProperty(prop));
}
}
错误
Exception in thread "main" java.lang.ClassCastException: java.lang.String cannot be cast to org.neo4j.graphdb.Node
at beans.RecommendationBean.queryMoviesWithCypher(RecommendationBean.java:194)
at beans.RecommendationBean.main(RecommendationBean.java:56)