java - neo4j 和 java 集合搜索

Question

您好，我正在尝试使用运算符 IN 进行搜索，但总是返回空列表，这是怎么回事？下面是我的单元测试。我想要的是通过描述或与描述相似的词来搜索产品。 (以后我假装实现模糊)。

private GraphDatabaseService graph;
private Index<Node> indexProduct;
private ExecutionEngine engine;

@Before
public void prepareTestDatabase() {
    TestGraphDatabaseFactory testGraphDatabaseFactory = new TestGraphDatabaseFactory();
    this.graph = testGraphDatabaseFactory.newEmbeddedDatabase("/tmp/neo4j/tests");
    this.indexProduct = this.graph.index().forNodes("node_product");
    this.engine = new ExecutionEngine(this.graph, StringLogger.SYSTEM);
    this.loadDataForTest();
}

private void loadDataForTest() {
    Transaction tx = this.graph.beginTx();

    List<String> similarities = new ArrayList<>();
    similarities.add("televisor");
    similarities.add("tv");
    String description = "televisão";
    Product product = new Product(description, similarities);

    Node node = this.graph.createNode(DynamicLabel.label(product.description));
    node.setProperty("description", product.description);
    node.setProperty("similarities", product.similarities);

    this.indexProduct.add(node, "PRODUCT", product.description);

    tx.success();
    tx.finish();
}

@Test
public void searchByDescription(){
    String description = "televisão";

    List<String> list = new ArrayList<>();
    ExecutionResult result = this.engine.execute("start n=node:node_product('PRODUCT:*') WHERE HAS(n.similarities) AND n.similarities IN ['tv'] return n.description");
    for (Map<String, Object> row : result) {
        for (Entry<String, Object> column : row.entrySet()) {
            Object value = column.getValue();
            list.add(String.valueOf(value));
        }
    }

    Assert.assertTrue(list.contains(description));
}

这是产品类别

class Product {
    String description;
String[] similarities;

Product(String description, List<String> similaritiesList) {
    super();
    this.description = description;
    this.similarities = new String[similaritiesList.size()];
    for (int i=0; i<similaritiesList.size(); i++)
        this.similarities[i] = similaritiesList.get(i);
}

Answer 1

我希望我的用例是正确的。但我认为您的 Cypher 查询有点困惑。您的查询:

"start n=node:node_product('PRODUCT:*') WHERE HAS(n.similarities) AND n.similarities IN ['tv'] return n.description"

让我们看看 ['tv'] 中的n.similarities。属性similarities是一个数组。 ['tv'] 是一个字符串数组。因此，表达式 `n.similarities IN ['tv'] 的计算结果始终为 false，因为 ['tv'] 不包含任何数组，更不用说similarities数组了。

最后我只是认为你的意思是别的。

 'tv' IN n.similarities

这可能是正确的吗？您想要检查字符串 tv 是否包含在 similarities 数组中。当我以这种方式更改查询时，即生成的查询将是

start n=node:node_product('PRODUCT:*') WHERE HAS(n.similarities) AND 'tv' IN n.similarities return n.description

然后，改编后的测试类对我有用。