在 OrientDB 中查询

Question

我尝试通过 java 控制台打印查询，但没有任何结果。 这是我的代码，有人可以帮助我。 我是 OrientDB 的新手，我只是在学习。 我需要的查询是知道两个节点之间的最短路径并在 Java 控制台上打印此查询。 它没有给我任何错误，但没有任何结果。

public class Graph {
    private static final String DB_PATH = "C:/OrientDataBase/shortest_path";
    static OrientGraphNoTx DBGraph;
    static OrientGraphFactory factory;

 public static void main(String[] args) {
        factory = new OrientGraphFactory("plocal:"+DB_PATH);
        DBGraph = factory.getNoTx();
        HashMap<String, Vertex> nodes = new HashMap<String, Vertex>();

    for(int i = 0; i <= 1000; i++)
    {
        Vertex v = DBGraph.addVertex("class:V");
        v.setProperty("vertexID", i+"");
        nodes.put(i+"", v);
    }


    try(BufferedReader br = new BufferedReader(new FileReader("C:/OrientDataBase/sp1.csv"))) {
        int i=0;
        for(String line; (line = br.readLine()) !=null ; ) {
            if(i==0){
                i++;
            }
            else{
            String[] vertices = line.split(",");
            String vertex1 = vertices[0];
            String vertex2 = vertices[1];
            String weight= vertices[2];
            vertex2 = vertex2.replaceAll(" ", "");

            Vertex v1 = nodes.get(vertex1);
            Vertex v2 = nodes.get(vertex2);


            Edge eLives = DBGraph.addEdge(null, v1, v2, "belongs");
            eLives.setProperty("weight", weight);
            System.out.println(v1+","+v2+","+weight);

            String query = "select expand(shortestPath) from (select shortestPath(#10:0,#10:2,BOTH))";

            Iterable<OrientVertex> res = DBGraph.command(new OCommandSQL(query)).execute();

            while(res.iterator().hasNext()){
            OrientVertex v = res.iterator().next();
            System.out.println("rid: "+v.getId().toString()+"\tn:"+v.getProperty("n"));
            }

            }
        }

    }
    catch (IOException e) {
        e.printStackTrace();
    }



}
}

Answer 1

我试过你的代码，你必须在查询时打勾，它变成：

String query = "select expand(shortestPath) from (select shortestPath(#10:0,#10:2,'BOTH'))";

我使用了这个 csv 文件。

希望能帮助到你。

问候