Neo4j部署及简单使用（API调用）

目录

• 一、下载安装
• 二、基本CQL命令
• 三、JAVA API
• 四、- - -

一、下载安装

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• 下载地址
  
  
• 解压，配置环境变量

NEO4J_HOME

• 启动报错
  

警告: ERROR! Neo4j cannot be started using java version 1.8.0_151
警告: * Please use Oracle(R) Java(TM) 11, OpenJDK(TM) 11 to run Neo4j Server.
* Please see https://neo4j.com/docs/ for Neo4j installation instructions.
Invoke-Neo4j : This instance of Java is not supported
所在位置 D:softneo4j-community-4.4.8binneo4j.ps1:21 字符: 7
+ Exit (Invoke-Neo4j -Verbose:$Arguments.Verbose -CommandArgs $Argument ...
+       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,Invoke-Neo4j

4.x要求Java11+版本，重新下载3.X版本，重新配置环境变量

首先执行neo4j install-service命令

报错，目前配置的是jdk开发环境，需要指定运行环境：

• 指定jdk

set JAVA_HOME=D:softjdk1.8.151jre

• 再次执行安装、启动命令
  先执行neo4j install-service，否则start、stop命令无法使用

C:Userslenovo>neo4j start
Service start failed - service 'neo4j' not found

C:Userslenovo>neo4j install-service
Neo4j service installed

C:Userslenovo>neo4j start
Neo4j service started

C:Userslenovo>

• 登录

http://localhost:7474/browser/

用户密码:neo4j/neo4j

二、基本CQL命令

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相当于SQL

• 创建

CREATE (emp:Employee{id:123,name:"Lokesh",sal:35000,deptno:10})

• 查询

 MATCH (emp:Employee) return emp

必须搭配return或者update使用：

• 删除

MATCH (emp:Employee) delete emp

三、JAVA API

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参照官网资料
demo 源码下载

package com.renxiaozhao.neo4j;

import java.io.File;

import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;

public class Neo4jJavaApi {

    public static void main(String[] args) {

        GraphDatabaseService graphDb;
        Node firstNode;
        Node secondNode;
        Relationship relationship;
        graphDb = new GraphDatabaseFactory()
                .newEmbeddedDatabase(new File("D:\soft\neo4j-community-3.5.34\data\databases\testdb"));
        try (Transaction tx = graphDb.beginTx()) {
            firstNode = graphDb.createNode();
            firstNode.setProperty("message", "Hello, ");
            secondNode = graphDb.createNode();
            secondNode.setProperty("message", "World!");

            relationship = firstNode.createRelationshipTo(secondNode, RelTypes.KNOWS);
            relationship.setProperty("message", "brave Neo4j ");
            tx.success();
            System.out.print(firstNode.getProperty("message"));
            System.out.print(relationship.getProperty("message"));
            System.out.print(secondNode.getProperty("message"));
        } catch (Exception e) {
            System.out.println(e);
        } finally {
            graphDb.shutdown();
        }
    }

    private enum RelTypes implements RelationshipType {
        KNOWS
    }
    
}

• 执行demo,确保此时neo4j处于stop状态
  
• 启动neo4j,可以查看到写入的数据
  

执行程序时，neo4j必须处于关闭状态

启动neo4j查看数据时，需要指定程序所创建的数据库

除此之外还有通过driven连接neo4j的方式(类似jdbc)以及spring提供的功能模块，下次继续，今晚来医院太匆忙，手机要没电了，明天还要手术呢

四、- - -

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暑期编程PK赛 得CSDN机械键盘等精美礼品！