Neo4j Traverser - 只需获取特定类型的项目

Question

从任何给定的节点开始，我想运行遍历器，直到它到达具有“contentpage”类型的节点（所有节点都有类型属性）。

我已经用下面的遍历器尝试过，

{
    "order":"depth first",
    "uniqueness" : "node global",
    "relationships":[
        {"type":"CONTAINS","direction":"in"},
        {"type":"HAS","direction":"in"}
    ],
    "prune evaluator":{"language":"javascript","body":"position.endNode().getProperty('type')!='contentpage';"},
    "max depth":10000000
}

但我得到的只是 HTTP-Error 500。 有什么想法吗？

编辑：这是一个堆栈跟踪（我对它进行了一些修剪，因为它很大）

Problem accessing /db/data/node/782350/traverse/node. Reason:

    javax.script.ScriptException: sun.org.mozilla.javascript.WrappedException: Wrapped org.neo4j.graphdb.NotFoundException: type property not found for NodeImpl#782348. (<Unknown Source>#1) in <Unknown Source> at line number 1
Caused by:

org.neo4j.server.rest.domain.EvaluationException: javax.script.ScriptException: sun.org.mozilla.javascript.WrappedException: Wrapped org.neo4j.graphdb.NotFoundException: type property not found for NodeImpl#782348. (<Unknown Source>#1) in <Unknown Source> at line number 1
    at org.neo4j.server.rest.domain.EvaluatorFactory$CompiledScriptExecutor.eval(EvaluatorFactory.java:183)
    at org.neo4j.server.rest.domain.EvaluatorFactory$ScriptedPruneEvaluator.pruneAfter(EvaluatorFactory.java:241)
    at org.neo4j.kernel.impl.traversal.TraversalDescriptionImpl$WrappedPruneEvaluator.evaluate(TraversalDescriptionImpl.java:239)
    at org.neo4j.kernel.impl.traversal.MultiEvaluator.evaluate(MultiEvaluator.java:41)
    at org.neo4j.kernel.impl.traversal.TraversalBranchImpl.initialize(TraversalBranchImpl.java:93)
    at org.neo4j.kernel.impl.traversal.TraversalBranchImpl.next(TraversalBranchImpl.java:112)
    at org.neo4j.kernel.impl.traversal.StartNodeTraversalBranch.next(StartNodeTraversalBranch.java:50)
    at org.neo4j.kernel.PreorderDepthFirstSelector.next(PreorderDepthFirstSelector.java:48)
    at org.neo4j.kernel.impl.traversal.TraverserImpl$TraverserIterator.fetchNextOrNull(TraverserImpl.java:127)
    at org.neo4j.kernel.impl.traversal.TraverserImpl$TraverserIterator.fetchNextOrNull(TraverserImpl.java:94)
    at org.neo4j.helpers.collection.PrefetchingIterator.hasNext(PrefetchingIterator.java:55)
    at org.neo4j.server.rest.web.DatabaseActions.traverse(DatabaseActions.java:922)
    at org.neo4j.server.rest.web.RestfulGraphDatabase.traverse(RestfulGraphDatabase.java:641)
    at sun.reflect.GeneratedMethodAccessor99.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)

Answer 1

首先，似乎您应该具有

 "uniqueness" : "node global"

一般情况下，您不能发送空值。如果您想要默认值，请不要设置任何内容。请参阅此处了解更多信息：Neo4j REST API。

编辑更新的问题：

因此异常显示：

NotFoundException: type property not found for NodeImpl

这是由以下原因引起的：

position.endNode().getProperty('type')

要避免这种情况，请为属性设置默认值，例如：

getProperty('type','')

Answer 2

您可以查看 data/log/*.log 和 data/messages.log 文件以获取可能的堆栈跟踪吗？

谢谢