Eclipse下maven使用嵌入式（Embedded）Neo4j创建Hello World项目

新建一个maven工程，这里不赘述如何新建maven工程。

添加Neo4j jar到你的工程

有两种方式：

• 上网站官网下载jar包，根据自己的系统下载不同的压缩包，详细过程不描述，请自行搜索其他博客
• 通过maven获得jar包

pom.xml文件下添加dependency

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <groupId>nd.esp.com</groupId>  <artifactId>MyNeo4j</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>MyNeo4j</name>  <url>http://maven.apache.org</url>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  </properties><!-- Embedded Neo4j依赖，目前最新版本是2.3.3-->  <dependencies>    <dependency>     <groupId>org.neo4j</groupId>     <artifactId>neo4j-slf4j</artifactId>     <version>2.3.3</version>    </dependency>  </dependencies></project>

Hello World 程序

代码可以在github上看到：https://github.com/neo4j/neo4j/blob/2.3.3/community/embedded-examples/src/main/java/org/neo4j/examples/EmbeddedNeo4j.java

/* * Licensed to Neo Technology under one or more contributor * license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright * ownership. Neo Technology licenses this file to you under * the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */package org.neo4j.examples;import java.io.File;import java.io.IOException;import org.neo4j.graphdb.Direction;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;import org.neo4j.io.fs.FileUtils;public class EmbeddedNeo4j{    // Embedded Neo4j会在本地产生一个文件夹(类似于Mysql的数据库)    private static final String DB_PATH = "target/neo4j-hello-db";    public String greeting;    // START SNIPPET: vars    GraphDatabaseService graphDb;    Node firstNode;    Node secondNode;    Relationship relationship;    // END SNIPPET: vars    // START SNIPPET: createReltype    private static enum RelTypes implements RelationshipType    {        KNOWS    }    // END SNIPPET: createReltype    public static void main( final String[] args ) throws IOException    {        EmbeddedNeo4j hello = new EmbeddedNeo4j();        hello.createDb();        // 删除数据        hello.removeData();        hello.shutDown();    }    void createDb() throws IOException    {        FileUtils.deleteRecursively( new File( DB_PATH ) );        // START SNIPPET: startDb        graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );        registerShutdownHook( graphDb );        // END SNIPPET: startDb        // START SNIPPET: transaction        // Embedded Neo4j基本上所有的操作都需要在事务内执行        try ( Transaction tx = graphDb.beginTx() )        {            // Database operations go here            // END SNIPPET: transaction            // START SNIPPET: addData            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 " );            // END SNIPPET: addData            // START SNIPPET: readData            System.out.print( firstNode.getProperty( "message" ) );            System.out.print( relationship.getProperty( "message" ) );            System.out.print( secondNode.getProperty( "message" ) );            // END SNIPPET: readData            greeting = ( (String) firstNode.getProperty( "message" ) )                       + ( (String) relationship.getProperty( "message" ) )                       + ( (String) secondNode.getProperty( "message" ) );            // START SNIPPET: transaction            tx.success();        }        // END SNIPPET: transaction    }    // 移除新建的数据    void removeData()    {        try ( Transaction tx = graphDb.beginTx() )        {            // START SNIPPET: removingData            // let's remove the data            firstNode.getSingleRelationship( RelTypes.KNOWS, Direction.OUTGOING ).delete();            firstNode.delete();            secondNode.delete();            // END SNIPPET: removingData            tx.success();        }    }    // 关闭Neo4j 数据库    void shutDown()    {        System.out.println();        System.out.println( "Shutting down database ..." );        // START SNIPPET: shutdownServer        graphDb.shutdown();        // END SNIPPET: shutdownServer    }    // 为Neo4j 实例注册一个关闭的hook，当VM被强制退出时，Neo4j 实例能够正常关闭    private static void registerShutdownHook( final GraphDatabaseService graphDb )    {        // Registers a shutdown hook for the Neo4j instance so that it        // shuts down nicely when the VM exits (even if you "Ctrl-C" the        // running application).        Runtime.getRuntime().addShutdownHook( new Thread()        {            @Override            public void run()            {                graphDb.shutdown();            }        } );    }}在事务中操作所有的操作都必须在一个事务中完成。这是官方一个刻意的设计，因为他们坚信事务划分是企业型数据库重要的一部分。所以，你可以使用如下的方式开启事务：try ( Transaction tx = graphDb.beginTx() ){// Database operations go heretx.success();}try(){}这种语法是在jdk1.7之后支持的，这种方式能够让vm支持自动释放使用结束的资源。在这里可以不需要自己调用语句:finally{tx.close();}如果你使用低于jdk1.7以后的版本，可以修改为如下的代码：Transaction tx = graphDb.beginTx()try{// Database operations go heretx.success();}finally{tx.close();}创建一个简单的图使用一下代码创建两个节点和一个关系：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 " );

创建之后的图数据如下：

本文翻译自官网使用手册：http://neo4j.com/docs/stable/tutorials-java-embedded-hello-world.html