java - 如何通过 OrientDB java api 使用标签/类获取边缘

Question

我想通过 java api 使用一个或多个类/标签从一个顶点开始获取外边。

这是我的示例代码，它会导致 NPE。 我尝试使用 Edge 和 OrientEdge。

private Iterable<OrientEdge> queryNextEdges(OrientVertex vertex) {
    OrientGraphFactory factory = new OrientGraphFactory(
            "remote:127.0.0.1:2424/xyz", "admin", "admin"
    ).setupPool(1, 10);
    OrientGraph graph = factory.getTx();
    Iterable<OrientEdge> queryResult;
    try {
        queryResult = (Iterable<OrientEdge>) (OrientEdge) vertex.getEdges(Direction.OUT, "hierarchy");
    } finally {
        graph.shutdown();
    }
    return queryResult;
}

错误:

Caused by: java.lang.NullPointerException
at com.tinkerpop.blueprints.impls.orient.OrientVertex.getFieldNames(OrientVertex.java:1042)
at com.tinkerpop.blueprints.impls.orient.OrientVertex.getEdges(OrientVertex.java:810)
at com.tinkerpop.blueprints.impls.orient.OrientVertex.getEdges(OrientVertex.java:782)
at ebs.window.graphLayout.GraphLayoutPresenter.queryNextEdges(GraphLayoutPresenter.java:214)

Answer 1

我尝试重现您的示例并且它有效。

希望有帮助。