Mysql+neo4j创建节点和关系

 本地安装好Neo4j：清除所有的节点和关系

 代码流程解读

1. 清除 Neo4j 中的现有数据

java复制代码

session.run("MATCH (n) DETACH DELETE n");

• 在创建新节点和关系之前，首先执行 MATCH (n) DETACH DELETE n，这会删除 Neo4j 中的所有节点和它们的关系，以确保不会有旧的数据干扰。

2. 从 MySQL 数据库中读取数据并创建节点

代码中有多个 PreparedStatement 来查询 MySQL 中的三张不同表，并从中读取数据来创建 Neo4j 节点。

2.1 创建第一个表的节点

java复制代码

PreparedStatement stmt1 = mysqlConn.prepareStatement("SELECT id, unit_name FROM zcdmx_rela_ship"); ResultSet rs1 = stmt1.executeQuery(); while (rs1.next()) { long id = rs1.getLong("id"); String name = rs1.getString("unit_name"); session.run("CREATE (:Node {id: $id, name: $unit_name})", Map.of("id", id, "unit_name", name)); }

• 从 zcdmx_rela_ship 表中读取 id 和 unit_name 字段。
• 每一行数据会对应一个新的节点，节点类型为 Node，并且包含 id 和 unit_name 两个属性。

2.2 创建第二个表的节点

java复制代码

PreparedStatement stmt2 = mysqlConn.prepareStatement("SELECT id, hyfl_name FROM zcdmx_rela_ship_hyfl"); ResultSet rs2 = stmt2.executeQuery(); while (rs2.next()) { long id = rs2.getLong("id"); String key = rs2.getString("hyfl_name"); session.run("CREATE (:Node {id: $id, name: $hyfl_name})", Map.of("id", id, "hyfl_name", key)); }

• 从 zcdmx_rela_ship_hyfl 表中读取 id 和 hyfl_name 字段。
• 每一行数据同样会创建一个新的节点，节点属性包括 id 和 hyfl_name。

2.3 创建第三个表的节点及关系

java复制代码

PreparedStatement stmt3 = mysqlConn.prepareStatement("SELECT id, extend_first, extend_second, extend_fourth,extend_five,extend_six,extend_eight,extend_nine FROM knowledge_base_details"); ResultSet rs3 = stmt3.executeQuery(); while (rs3.next()) { // 读取各字段 String extend_first = rs3.getString("extend_first"); String extend_second = rs3.getString("extend_second"); String extend_fourth = rs3.getString("extend_fourth"); String extend_five = rs3.getString("extend_five"); String extend_six = rs3.getString("extend_six"); String extend_eight = rs3.getString("extend_eight"); String extend_nine = rs3.getString("extend_nine"); // 创建节点 session.run("MERGE (:Node {name: $extend_fourth, extend_first: $extend_first, extend_second: $extend_second, extend_five: $extend_five, extend_six: $extend_six, extend_eight: $extend_eight, extend_nine: $extend_nine})", Map.of( "extend_first", extend_first, "extend_second", extend_second, "extend_five", extend_five, "extend_six", extend_six, "extend_eight", extend_eight, "extend_nine", extend_nine, "extend_fourth", extend_fourth )); // 创建关系：extend_first 和 extend_fourth 之间的关系 if (StrUtil.isAllNotBlank(extend_fourth, extend_first)) { session.run("MATCH (a:Node {name: $nameV}), (b:Node {name: $world}) " + "CREATE (a)-[:RELATES_TO]->(b)", Map.of("nameV", extend_fourth, "world", extend_first)); } // 创建关系：extend_nine 和 extend_fourth 之间的关系 if (StrUtil.isAllNotBlank(extend_fourth, extend_nine)) { session.run("MATCH (a:Node {name: $keyV}), (b:Node {name: $world}) " + "CREATE (a)-[:RELATES_TO]->(b)", Map.of("keyV", extend_nine, "world", extend_fourth)); } }

• 从 knowledge_base_details 表中读取多个字段。根据这些字段，创建一个 Node 类型的节点，并设置多个属性。
• 使用 MERGE 来确保节点是唯一的，避免重复创建。
• 在一些字段非空时，创建节点之间的关系，使用 RELATES_TO 关系类型连接相关的节点。

3. 关键步骤解析

• 清除现有数据：通过 MATCH (n) DETACH DELETE n 删除现有的所有节点和关系，避免数据重复或不一致。

• 读取 MySQL 数据：通过多次执行 PreparedStatement 和 ResultSet 读取 MySQL 中的多张表，并根据这些数据创建 Neo4j 节点。

• 创建节点：每次读取一行数据，都会在 Neo4j 中创建一个 Node 节点，并根据表的字段设置相应的属性。

• 创建关系：通过 MATCH 和 CREATE 创建节点之间的关系。这里使用了 RELATES_TO 作为关系类型，表示节点间的关联。

4. 节点和关系效果

• 节点效果：您将看到多个 Node 节点，它们分别对应不同的表（如 zcdmx_rela_ship、zcdmx_rela_ship_hyfl 和 knowledge_base_details），并包含表中的各个字段。

• 关系效果：不同的节点之间会形成多个 RELATES_TO 关系。例如，extend_first 和 extend_fourth 之间会有一条关系，extend_nine 和 extend_fourth 之间也会有一条关系。

代码操作生成节点和关系：源代码

package com.gt.demo.mcpserver.utils;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Map;

import cn.hutool.core.util.StrUtil;
import org.neo4j.driver.AuthTokens;
import org.neo4j.driver.Driver;
import org.neo4j.driver.GraphDatabase;
import org.neo4j.driver.Session;

@SuppressWarnings("all")
public class MySqlToNeo4j {

    private static final String MYSQL_URL = "jdbc:mysql://localhost:16002/jcfx_zcdmx";
    private static final String MYSQL_USER = "root";
    private static final String MYSQL_PASSWORD = "root@123456";

    private static final String NEO4J_URI = "bolt://localhost:7687";
    private static final String NEO4J_USER = "neo4j";
    private static final String NEO4J_PASSWORD = "123456";

    public static void main(String[] args) {
        try (Connection mysqlConn = DriverManager.getConnection(MYSQL_URL, MYSQL_USER, MYSQL_PASSWORD);
             Driver neo4jDriver = GraphDatabase.driver(NEO4J_URI, AuthTokens.basic(NEO4J_USER, NEO4J_PASSWORD))) {
            System.out.println("开始------");
            // Create nodes and relationships in Neo4j
            createNodesAndRelationships(mysqlConn, neo4jDriver);
            System.out.println("结束------");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Creates nodes and relationships in a Neo4j database based on data from a MySQL database.
     * This method reads data from three different tables in the MySQL database, creates corresponding nodes in the Neo4j database,
     * and establishes relationships between these nodes based on specific conditions.
     *
     * @param mysqlConn   A connection object to the MySQL database, used to execute SQL statements and retrieve data.
     * @param neo4jDriver A driver object for the Neo4j database, used to manage the session with the Neo4j database.
     * @throws Exception Throws an exception if there is an error during database operations or data processing.
     */
    private static void createNodesAndRelationships(Connection mysqlConn, Driver neo4jDriver) throws Exception {
        try (Session session = neo4jDriver.session()) {
            // Clear existing data in Neo4j (optional)
            session.run("MATCH (n) DETACH DELETE n");

            // Read data from the first table and create nodes
            PreparedStatement stmt1 = mysqlConn.prepareStatement("SELECT id, unit_name FROM zcdmx_rela_ship");
            ResultSet rs1 = stmt1.executeQuery();
            while (rs1.next()) {
                long id = rs1.getLong("id");
                String name = rs1.getString("unit_name");
                session.run("CREATE (:Node {id: $id, name: $unit_name})", Map.of("id", id, "unit_name", name));
            }

            // Read data from the second table and create nodes
            PreparedStatement stmt2 = mysqlConn.prepareStatement("SELECT id, hyfl_name FROM zcdmx_rela_ship_hyfl");
            ResultSet rs2 = stmt2.executeQuery();
            while (rs2.next()) {
                long id = rs2.getLong("id");
                String key = rs2.getString("hyfl_name");
                session.run("CREATE (:Node {id: $id, name: $hyfl_name})", Map.of("id", id, "hyfl_name", key));
            }

            // Read data from the third table and create nodes and relationships
            PreparedStatement stmt3 = mysqlConn.prepareStatement("SELECT id, extend_first, extend_second, extend_fourth,extend_five,extend_six,extend_eight,extend_nine FROM knowledge_base_details");
            ResultSet rs3 = stmt3.executeQuery();
            while (rs3.next()) {
                long id = rs3.getLong("id");
                String extend_first = rs3.getString("extend_first");
                String extend_second = rs3.getString("extend_second");
                String extend_fourth = rs3.getString("extend_fourth");
                String extend_five = rs3.getString("extend_five");
                String extend_six = rs3.getString("extend_six");
                String extend_eight = rs3.getString("extend_eight");
                String extend_nine = rs3.getString("extend_nine");

                // Create node for world if it doesn't exist
                session.run("MERGE (:Node {name: $extend_fourth,extend_first : $extend_first, extend_second : $extend_second, extend_five: $extend_five,extend_six: $extend_six,extend_eight: $extend_eight,extend_nine: $extend_nine})", Map.of(
                        "id", id,
                        "extend_first", StrUtil.blankToDefault(extend_first, ""),
                        "extend_second", StrUtil.blankToDefault(extend_second, ""),
                        "extend_five", StrUtil.blankToDefault(extend_five, ""),
                        "extend_six", StrUtil.blankToDefault(extend_six, ""),
                        "extend_eight", StrUtil.blankToDefault(extend_eight, ""),
                        "extend_nine", StrUtil.blankToDefault(extend_nine, ""),
                        "extend_fourth", StrUtil.blankToDefault(extend_fourth, "")));
                if (StrUtil.isAllNotBlank(extend_fourth, extend_first)) {
                    // Create relationship between Node(nameV) and Node(world)
                    session.run(
                            "MATCH (a:Node {name: $nameV}), (b:Node {name: $world}) " +
                            "CREATE (a)-[:RELATES_TO]->(b)",
                            Map.of("nameV", extend_fourth, "world", extend_first)
                    );
                }
                // Create relationship between Node(keyV) and Node(world)
                if (StrUtil.isAllNotBlank(extend_fourth, extend_nine)) {
                    session.run(
                            "MATCH (a:Node {name: $keyV}), (b:Node {name: $world}) " +
                            "CREATE (a)-[:RELATES_TO]->(b)",
                            Map.of("keyV", extend_nine, "world", extend_fourth)
                    );
                }
            }
        }
    }

}

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