Question

假设我有一个顶点人的列表，其属性为名称，年龄。我想编写一个查询，结果是一个顶点name="John" and age=22。

Pipe pipe = (Pipe) new GremlinPipeline(graph).V().has("name", "John");
Pipe pipe2=new GremlinPipeline(graph).V().has("age", "22");
List<Vertex>  verList = (List<Vertex>) new GremlinPipeline(graph).V().and(pipe,pipe2).toList();

我不知道这是否是实现它的正确方法。它抛出以下异常

Exception in thread "main" java.lang.ClassCastException: com.thinkaurelius.titan.graphdb.vertices.CacheVertex cannot be cast to com.tinkerpop.blueprints.Graph
at com.tinkerpop.pipes.transform.GraphQueryPipe.processNextStart(GraphQueryPipe.java:33)
at com.tinkerpop.pipes.transform.GraphQueryPipe.processNextStart(GraphQueryPipe.java:17)
at com.tinkerpop.pipes.AbstractPipe.next(AbstractPipe.java:89)
at com.tinkerpop.pipes.IdentityPipe.processNextStart(IdentityPipe.java:19)
at com.tinkerpop.pipes.AbstractPipe.hasNext(AbstractPipe.java:98)
at com.tinkerpop.pipes.util.Pipeline.hasNext(Pipeline.java:105)
at com.tinkerpop.pipes.transform.HasNextPipe.processNextStart(HasNextPipe.java:36)
at com.tinkerpop.pipes.transform.HasNextPipe.processNextStart(HasNextPipe.java:16)
at com.tinkerpop.pipes.AbstractPipe.next(AbstractPipe.java:89)
at com.tinkerpop.pipes.filter.AndFilterPipe.processNextStart(AndFilterPipe.java:35)
at com.tinkerpop.pipes.AbstractPipe.next(AbstractPipe.java:89)
at com.tinkerpop.pipes.util.Pipeline.next(Pipeline.java:115)
at com.tinkerpop.pipes.util.PipeHelper.fillCollection(PipeHelper.java:52)
at com.tinkerpop.gremlin.java.GremlinPipeline.toList(GremlinPipeline.java:1564)
at BulkLoad_New.search(BulkLoad_New.java:320)
at BulkLoad_New.main(BulkLoad_New.java:71)

Answer 1

我认为这里不需要使用and步骤。只需管道两个has条件：

g.V.has('name','John').has('age',22)

这实际上是一个AND操作。在Java中我猜这将是：

new GremlinPipeline(graph).V().has("name", "John").has("age",22);

请阅读this post，了解如何从groovy转换为java以获取有关该主题的更多信息。

如何在GremlinPipeLine中使用“AND”条件

1 个答案: