将密码查询的结果收集到哈希映射java中？ [英] Collecting the result of cypher query into a hash map java?

问题描述

这是查找连接节点的后续问题。

代码是

  firstNode = graphDb.createNode（）; //创建节点
 firstNode.setProperty（person，Andy）; 
 Label myLabel = DynamicLabel.label（person）; 
 firstNode.addLabel（myLabel）; ... 
 
 relationship = firstNode.createRelationshipTo（secondNode，RelTypes.emails）; //创建关系
 relationship.setProperty（relationship，email）; .... 
 
 
 ExecutionEngine engine = new ExecutionEngine（graphDb）; 
 ExecutionResult result = engine.execute（MATCH（sender：person） -  [：emails]  - （receiver）RETURN sender，count（receiver）as count，collect（receiver）as ORDER BY count DESC）; 
 System.out.println（result.dumpToString（））; 
  

我得到的结果是：

  sender | count |接收者
节点[2] {person：Chris} | 3 | [节点[4] {person：Elsa}，Node [0] {person：Andy}，Node [1] {person：Bobby}] 
 Node [4] {person：Elsa } | 3 | [节点[5] {person：Frank}，Node [2] {person：Chris}，Node [3] {person：David}] 
 Node [1] {person：Bobby } | 3 | [节点[2] {person：Chris}，Node [3] {person：David}，Node [0] {person：Andy}] 
 Node [5] {person：Frank } | 2 | [节点[3] {person：David}，Node [4] {person：Elsa} 
  

如何收集发件人作为关键字和接收者作为值？
例如： {Frank = [David，Elsa]，Chris = [Elsa，Andy，Nobby] ..

有什么想法？

最初我尝试迭代类似的东西（Map< / p>

  String，Object> row：result）{
 Node x =（Node）row.get（receivers）; 
 System.out.println（x）; （String prop：x.getPropertyKeys（））{
 System.out.println（prop +：+ x.getProperty（prop））; 
 
 for 
 
} 
  

这引发了classcast异常。它适用于列发件人而不是接收者。

我对cypher很新颖。我不知道如何将结果转换为哈希映射。这可能是什么？

解决方案

您可以重写密码以返回地图，而不是...（为了便于阅读， （发件人：人） - [：电子邮件] - >（收件人）
与发件人，收件人（收件人）。人）作为接收者
RETURN {发送者：发送者，接收者：接收者）
ORDER BY大小（接收者）DESC

This is a followup of Finding connected nodes question.

The code is

    firstNode = graphDb.createNode();//creating nodes
    firstNode.setProperty( "person", "Andy " ); 
    Label myLabel = DynamicLabel.label("person");
    firstNode.addLabel(myLabel); ...

    relationship = firstNode.createRelationshipTo( secondNode, RelTypes.emails );// creating relationships
    relationship.setProperty( "relationship", "email " );....


    ExecutionEngine engine = new ExecutionEngine(graphDb);
        ExecutionResult result = engine.execute("MATCH (sender:person)-[:emails]- (receiver)RETURN sender,  count(receiver)as count, collect(receiver) as receivers ORDER BY count DESC ");
        System.out.println(result.dumpToString());

The result I got was:

 sender                  | count | receivers                                                                 
Node[2]{person:"Chris"} | 3     | [Node[4]{person:"Elsa "},Node[0]{person:"Andy "},Node[1]{person:"Bobby"}] 
Node[4]{person:"Elsa "} | 3     | [Node[5]{person:"Frank"},Node[2]{person:"Chris"},Node[3]{person:"David"}]
Node[1]{person:"Bobby"} | 3     | [Node[2]{person:"Chris"},Node[3]{person:"David"},Node[0]{person:"Andy "}]
Node[5]{person:"Frank"} | 2     | [Node[3]{person:"David"},Node[4]{person:"Elsa "}

How to collect the sender as key and receivers as values? For ex : {Frank =[David, Elsa], Chris =[Elsa, Andy, Nobby]..

Any idea?

Initially I tried iterating something like this

        for (Map<String,Object> row : result) {
               Node x = (Node)row.get("receivers");
               System.out.println(x);

               for (String prop : x.getPropertyKeys()) {
                  System.out.println(prop +": "+x.getProperty(prop));

               }

This throws classcast exception. It works for column "sender" and not for "receivers".

I am very new to cypher. I don't know how to transform the result into a hash map. How is this possible ?

解决方案

You can rewrite the cypher to return a map instead... (split for readability)

MATCH (sender:person)-[:emails]->(receiver)
WITH sender, collect(receiver.person) as receivers
RETURN {sender: sender.person,  receivers: receivers)
ORDER BY size(receivers) DESC

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