neo4j java密码参数不起作用答案

【问题标题】：neo4j java cypher parameters not workingneo4j java密码参数不起作用
【发布时间】：2018-09-04 07:55:15
【问题描述】：

我正在尝试在图中创建一些虚拟节点：

    private final static Driver driver = GraphDatabase.driver("bolt://localhost:7687",
        AuthTokens.basic("neo4j", "password"));
    static Session session = driver.session();

    String cypher = "CREATE "
            + "(:GPPocEntity {id:'{gppeid}',gppe_out_prop_1:'{gppe_out_prop_1_val_id}',"
            +                           "gppe_out_prop_2:'{gppe_out_prop_2_val_id}',"
            +                           "gppe_out_prop_X:'{gppe_out_prop_X_val_id}'})"
            + "-[:has]->"
            + "(:PPocEntity {id:'{ppeid}',ppe_out_prop_1:'{ppe_out_prop_1_val_id}',"
            +                           "ppe_out_prop_2:'{ppe_out_prop_2_val_id}',"
            +                           "ppe_out_prop_X:'{ppe_out_prop_X_val_id}'})"
            + "-[:contains]->"
            + "(:PocEntity {id:'{peid}',pe_out_prop_1:'{pe_out_prop_1_val_id}',"
            +                           "pe_out_prop_2:'{pe_out_prop_2_val_id}',"
            +                           "pe_out_prop_X:'{pe_out_prop_X_val_id}'})";

    Map<String, Object> params = new HashMap<String, Object>();
    int id = 1111;
    params.put("gppeid","gppe"+id);
    params.put("ppeid","ppe"+id);
    params.put("peid","pe"+id);
    params.put("gppe_out_prop_1_val_id","gppe_out_prop_1_val_"+id);
    params.put("gppe_out_prop_2_val_id","gppe_out_prop_2_val_"+id);
    params.put("gppe_out_prop_X_val_id","gppe_out_prop_X_val_"+id);
    params.put("ppe_out_prop_1_val_id","ppe_out_prop_1_val_"+id);
    params.put("ppe_out_prop_2_val_id","ppe_out_prop_2_val_"+id);
    params.put("ppe_out_prop_X_val_id","ppe_out_prop_X_val_"+id);
    params.put("pe_out_prop_1_val_id","pe_out_prop_1_val_"+id);
    params.put("pe_out_prop_2_val_id","pe_out_prop_2_val_"+id);
    params.put("pe_out_prop_X_val_id","pe_out_prop_X_val_"+id);

    session.run(cypher, params);

但这并没有在密码中设置这些参数。为什么会这样？

【问题讨论】：

标签： neo4j cypher

【解决方案1】：

问题是您将密码查询中的参数用单引号括起来，因此它们不会被解释。尝试通过删除单引号来更正查询：

String cypher = "CREATE "
        + "(:GPPocEntity {id:{gppeid}, gppe_out_prop_1: {gppe_out_prop_1_val_id},  "
        + "                            gppe_out_prop_2: {gppe_out_prop_2_val_id},  "
        + "                            gppe_out_prop_X: {gppe_out_prop_X_val_id}}) "
        + "-[:has]->"
        ...

【讨论】：

【解决方案2】：

密码参数是$ + name，而不是{ + name + }。因此，对于名为gppe_out_prop_1_val_id 的参数，您应该将$gppe_out_prop_1_val_id 放入您的查询中。

而且您不需要在周围加上引号，输入参数，所以 Neo4j 会为您完成。

【讨论】：