Neo4j的使用与Java调用实例

一. Neo4j简介:

Neo4j是一个高性能的,NoSQL图形数据库,它将结构化数据存储在网络上而不是表中。它是一个嵌入式的、基于磁盘的、具备完全的事务特性的Java持久化引擎,但是它将结构化数据存储在网络(从数学角度叫做图)上而不是表中。Neo4j也可以被看作是一个高性能的图引擎,该引擎具有成熟数据库的所有特性。程序员工作在一个面向对象的、灵活的网络结构下而不是严格、静态的表中——但是他们可以享受到具备完全的事务特性、企业级的数据库的所有好处。

在一个图中包含两种基本的数据类型:Nodes(节点) 和 Relationships(关系)。Nodes 和 Relationships 包含key/value形式的属性。Nodes通过Relationships所定义的关系相连起来,形成关系型网络结构。

相比其他NoSQL数据库,Neo4j的特点在于可以建立关系,达到数据关联的目的。从某些方面来说,我觉得它甚至可以取代关系型数据库,而且不需要事先定义表结构,字段扩展非常方便。

它使用的查询语言是Cypher。


二. Neo4j的核心概念:

1. Nodes(节点)

节点包含多个标签和属性,就像是一个地铁站。

一个节点就是一条数据。

2. Relations(关系)

关系是用来连接两个节点的,也可以包含多个标签和属性,就像是地铁站之间的线路。

一个关系也是一条数据。

关系包括进和出两种方向。

3. Properties(属性)

类似于关系型数据库里面的字段,不用事先定义,可以动态添加。

4. Labels(标签)

表示节点或者关系的类型,可以有多个,使查询更加方便和高效。



三. Neo4j的配置和使用:

下载最新的Neo4j:http://neo4j.com/download/

解压后移动到Neo4j下的bin目录,启动命令:neo4j.bat console

Neo4j的使用与Java调用实例_第1张图片

默认端口:7474

可在conf/neo4j.conf里面修改配置

在浏览器输入localhost:7474,登录Neo4j进行操作,默认用户名/密码:neo4j/neo4j,登陆后需要立刻修改密码。

Neo4j的使用与Java调用实例_第2张图片

①:Cypher查询语句

②:各种Labels及其数量

③:节点和关系的图形界面

④:某节点包含的属性


四. Cypher的基本语法:

1. 创建节点:

CREATE (n:Label {name:"L1", type:"T1"})
可以理解成:INSERT INTO Label(name, type) VALUES("L1", "T1")

n是变量名,可以任意。Label是标签,可以有多个。{}里面是属性,可以有多个。

这个创建节点的例子中,包含了2个标签:

CREATE (n:Label:Test {name:"L1", type:"T1"})


2. 查找节点:

MATCH(a:Test) WHERE a.name="L1" RETURN a;
Neo4j的使用与Java调用实例_第3张图片

3. 创建多个节点和关系:

CREATE (节点1),(节点2),(节点3),(节点1)-[关系1]->(节点2),(节点2)-[关系2]->(节点3)

例:CREATE (a:Node), (b:Node), (a)-[:Relate]->(b)

如果已有Node,只想添加关联,可用下面这种方法:

MATCH(a:Node),(b:Node) WHERE ID(a)=230 AND ID(b)=231 CREATE (b)-[:R]->(a)

4. 模式匹配:

根据关联进行数据查询。

MATCH (a)-[:Have]-(b)-[:Have]-(c)-[:Have]-(d) WHERE a.name="G1" RETURN a,b,c,d

Neo4j的使用与Java调用实例_第4张图片


5. 更新节点:

MATCH(n:Label) WHERE n.name="N2" SET n.update = "2018-06-26" 


6. 删除节点:

MATCH(n) WHERE ID(n)=100 DELETE n

7. 查看语句分析:

在查询语句前加上

EXPLAIN

PROFILE


五. Java实现的接口和实例:

我用的是SpringBoot的项目,可以直接启动ConsumerClientApplication,不用放到Tomcat下。

1. pom.xml中引入neo4j的jar包:

	    
	    
	      org.neo4j.driver
	      neo4j-java-driver
	      1.5.0
	    
	    
	    
	        org.neo4j
	        neo4j
	        3.3.4
	    

2. 创建Code对象,用来传递参数:

package com.inesa.neo4j.entity;

public class Code {

	private String id;
	private String node;
	private String relation;
	private String property;
	private String label;

	private String nodeFromId;
	private String nodeFromLabel;
	private String nodeToId;
	private String nodeToLabel;
	
	private String where;
	private String update;
	private String result;
	
	public String getNode() {
		return node;
	}
	public void setNode(String node) {
		this.node = node;
	}
	public String getRelation() {
		return relation;
	}
	public void setRelation(String relation) {
		this.relation = relation;
	}
	public String getProperty() {
		return property;
	}
	public void setProperty(String property) {
		this.property = property;
	}
	public String getLabel() {
		return label;
	}
	public void setLabel(String label) {
		this.label = label;
	}
	public String getNodeFromId() {
		return nodeFromId;
	}
	public void setNodeFromId(String nodeFromId) {
		this.nodeFromId = nodeFromId;
	}
	public String getNodeToId() {
		return nodeToId;
	}
	public void setNodeToId(String nodeToId) {
		this.nodeToId = nodeToId;
	}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getNodeFromLabel() {
		return nodeFromLabel;
	}
	public void setNodeFromLabel(String nodeFromLabel) {
		this.nodeFromLabel = nodeFromLabel;
	}
	public String getNodeToLabel() {
		return nodeToLabel;
	}
	public void setNodeToLabel(String nodeToLabel) {
		this.nodeToLabel = nodeToLabel;
	}
	public String getWhere() {
		return where;
	}
	public void setWhere(String where) {
		this.where = where;
	}
	public String getUpdate() {
		return update;
	}
	public void setUpdate(String update) {
		this.update = update;
	}
	public String getResult() {
		return result;
	}
	public void setResult(String result) {
		this.result = result;
	}

}

3. 创建Controller,添加接口:

package com.inesa.neo4j.controller;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.neo4j.driver.v1.AuthTokens;
import org.neo4j.driver.v1.Driver;
import org.neo4j.driver.v1.GraphDatabase;
import org.neo4j.driver.v1.Record;
import org.neo4j.driver.v1.Session;
import org.neo4j.driver.v1.StatementResult;
import static org.neo4j.driver.v1.Values.parameters;

import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.inesa.common.entity.RestfulResult;
import com.inesa.common.utils.CommUtils;
import com.inesa.common.utils.Constants;
import com.inesa.neo4j.entity.Code;

/**
 * Controller
 * 
 * @author sun
 * @version 2018-06-01
 */
@RestController
@RequestMapping(value = "neo4j")
public class CodeController {
    
    private Driver createDrive(){
		return GraphDatabase.driver( "bolt://localhost:7687", AuthTokens.basic( "neo4j", "admin" ) );
    }
    
    @RequestMapping(value = "test")
	public void test(HttpServletRequest request, HttpServletResponse response) {
		RestfulResult restfulResult = new RestfulResult();
		
		try{			
			Driver driver = createDrive();
	        Session session = driver.session();
	        
	        session.run( "CREATE (a:Person {name: {name}, title: {title}})",
	                parameters( "name", "Arthur001", "title", "King001" ) );

	        StatementResult result = session.run( "MATCH (a:Person) WHERE a.name = {name} " +
	                                              "RETURN a.name AS name, a.title AS title",
	                parameters( "name", "Arthur001" ) );
	        
	        while ( result.hasNext() )
	        {
	            Record record = result.next();
	            System.out.println( record.get( "title" ).asString() + " " + record.get( "name" ).asString() + " " + record.get( "id" ).asString() );
	        }
	        
	        session.close();
	        driver.close();
			
		}catch(Exception e){
			restfulResult.setResult(Constants.RESULT_STATE_ERROR);
			restfulResult.setMessage(e.getMessage());
		}
		
    	CommUtils.printDataJason(response, restfulResult);
	}

	@RequestMapping(value = "save")
	public void save(HttpServletRequest request, HttpServletResponse response,
			@RequestBody Code code) {
    	
		RestfulResult restfulResult = new RestfulResult();
		
		try{	
			Driver driver = createDrive();
	        Session session = driver.session();
	        
	        StatementResult result =  session.run( "CREATE (a:" + code.getLabel() + " {" + code.getProperty() + "}) return a");
	        
	        while (result.hasNext())
	        {
	            Record record = result.next();
		        restfulResult.setData(record.fields().get(0).value().toString().replace("node<", "").replace(">", ""));
	        }
	        
	        session.close();
	        driver.close();
			
		}catch(Exception e){
			restfulResult.setResult(Constants.RESULT_STATE_ERROR);
			restfulResult.setMessage(e.getMessage());
		}
		
    	CommUtils.printDataJason(response, restfulResult);
	}

	@RequestMapping(value = "update")
	public void update(HttpServletRequest request, HttpServletResponse response,
			@RequestBody Code code) {
    	
		RestfulResult restfulResult = new RestfulResult();
		
		try{	
			Driver driver = createDrive();
	        Session session = driver.session();
	        
	        StatementResult result = session.run("MATCH (a:" + code.getLabel() + ") WHERE a." + code.getWhere() + " SET a." + code.getUpdate() + " return COUNT(a)");
	        
	        while (result.hasNext())
	        {
	            Record record = result.next();
		        restfulResult.setData(record.fields().get(0).value().toString());
	        }
	        
	        session.close();
	        driver.close();
			
		}catch(Exception e){
			restfulResult.setResult(Constants.RESULT_STATE_ERROR);
			restfulResult.setMessage(e.getMessage());
		}
		
    	CommUtils.printDataJason(response, restfulResult);
	}

    @RequestMapping(value = "delete")
	public void delete(HttpServletRequest request, HttpServletResponse response,
			@RequestBody Code code) {
		RestfulResult restfulResult = new RestfulResult();
		
		try{			
			Driver driver = createDrive();
	        Session session = driver.session();
	        session.run( "match (n) where ID(n) = " + code.getId() +" detach delete n");
	        
	        session.close();
	        driver.close();
			
		}catch(Exception e){
			restfulResult.setResult(Constants.RESULT_STATE_ERROR);
			restfulResult.setMessage(e.getMessage());
		}
		
    	CommUtils.printDataJason(response, restfulResult);
	}

    @RequestMapping(value = "search")
	public void search(HttpServletRequest request, HttpServletResponse response,
			@RequestBody Code code) {
		RestfulResult restfulResult = new RestfulResult();
		
		try{			
			Driver driver = createDrive();
	        Session session = driver.session();

	        StatementResult result = session.run("MATCH " + code.getProperty() +
	        									" MATCH " + code.getRelation() +
	        									" WHERE " + code.getWhere() +
	                                              " RETURN " + code.getResult());
	        List resultList = new ArrayList();
	        while ( result.hasNext() )
	        {
	            Record record = result.next();
	            resultList.add(record.get("id").toString() + " " + record.get("name").toString());
	        }
	        
	        session.close();
	        driver.close();
	        
	        restfulResult.setData(resultList);
			
		}catch(Exception e){
			restfulResult.setResult(Constants.RESULT_STATE_ERROR);
			restfulResult.setMessage(e.getMessage());
		}
		
    	CommUtils.printDataJason(response, restfulResult);
	}

    @RequestMapping(value = "relate")
	public void relate(HttpServletRequest request, HttpServletResponse response,
			@RequestBody Code code) {
		RestfulResult restfulResult = new RestfulResult();
		
		try{
			Driver driver = createDrive();
	        Session session = driver.session();
	        
	        session.run("MATCH (a:" + code.getNodeFromLabel() + "), (b:" + code.getNodeToLabel() + ") " +
	        		"WHERE ID(a) = " + code.getNodeFromId() + " AND ID(b) = " + code.getNodeToId()
	        		+ " CREATE (a)-[:" + code.getRelation() + "]->(b)");
	        
	        session.close();
	        driver.close();
			
		}catch(Exception e){
			restfulResult.setResult(Constants.RESULT_STATE_ERROR);
			restfulResult.setMessage(e.getMessage());
		}
		
    	CommUtils.printDataJason(response, restfulResult);
	}

	//private static final String DB_PATH = "D:/neo4j/data/databases/graph.db";
	
	//GraphDatabaseService graphDb;
	
	/*@RequestMapping(value = "save")
	public void save(HttpServletRequest request, HttpServletResponse response,
			@RequestBody Code code) {
    	
		RestfulResult restfulResult = new RestfulResult();
		
		try{		
			if (graphDb == null)
				this.graphDb = new GraphDatabaseFactory().newEmbeddedDatabase(new File(DB_PATH));
			
			registerShutdownHook(graphDb);
			
			Transaction tx = graphDb.beginTx();
		
			Node node = this.graphDb.createNode();
			Label label = DynamicLabel.label(code.getLabel());
			node.addLabel(label);
			node.setProperty("Name", code.getProperty());

            tx.success();
            
            restfulResult.setData(node.getId());
			
		}catch(Exception e){
			restfulResult.setResult(Constants.RESULT_STATE_ERROR);
			restfulResult.setMessage(e.getMessage());
		}
		
    	CommUtils.printDataJason(response, restfulResult);
	}*/
    
/*    private void registerShutdownHook(final GraphDatabaseService graphDB){
        //关闭寄存器
        Runtime.getRuntime().addShutdownHook(new Thread(){
            public void run(){
                graphDB.shutdown();
            }
        });
    }*/
}

我这里只是做了几个简单的Sample,调用方式如下:

(1) 创建节点(save)

Neo4j的使用与Java调用实例_第5张图片

(2) 删除节点(delete)

Neo4j的使用与Java调用实例_第6张图片

(3) 修改节点(update)

Neo4j的使用与Java调用实例_第7张图片

(4) 添加节点关系(relate)

Neo4j的使用与Java调用实例_第8张图片

(5) 自定义条件查询(search)

Neo4j的使用与Java调用实例_第9张图片

结果数据:

Neo4j的使用与Java调用实例_第10张图片

GitHub地址:https://github.com/sunroyi/neo4j.git

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