Neo4j学习（3）--JavaAPI

Neo4j Java操作

1. Neo4j Java Driver方式操作

使用该方式对数据进行操作时，必须先将Neo4j的服务启动起来。

从官方下载neo4j的Java驱动：https://neo4j.com/download-center/#drivers

将驱动导入eclipse的项目中，具体操作如下：

import org.neo4j.driver.v1.AuthTokens;
import org.neo4j.driver.v1.Driver;
import org.neo4j.driver.v1.GraphDatabase;
import org.neo4j.driver.v1.Session;
import org.neo4j.driver.v1.StatementResult;
import org.neo4j.driver.v1.Transaction;
import org.neo4j.driver.v1.TransactionWork;

import static org.neo4j.driver.v1.Values.parameters;

public class Neo4jConn implements AutoCloseable {

private final Driver driver;

public Neo4jConn(String uri, String user, String password) {
driver = GraphDatabase.driver(uri, AuthTokens.basic(user, password));
}

@Override
public void close() throws Exception {
driver.close();
}

public void printGreeting(final String message) {
try (Session session = driver.session()) {
String greeting = session.writeTransaction(new TransactionWork<String>() {
@Override
public String execute(Transaction tx) {
StatementResult result = tx.run("CREATE (a:Greeting) " + "SET a.message = $message "
+ "RETURN a.message + ', from node ' + id(a)", parameters("message", message));
return result.single().get(0).asString();
}
});
System.out.println(greeting);
}
}

public static void main(String... args) throws Exception {
try (Neo4jConn greeter = new Neo4jConn("bolt://localhost:7687", "neo4j", "123456")) {
System.out.println("get conn!!!");
greeter.printGreeting("hello, world");
}
}
}

2.Neo4j 嵌入式（Embedded）Java AP方式操作，包含Native JAVA API 和Cypher JAVA API两种方式

使用该方式时，必选先停止Neo4j的服务，否则报错：

java.io.IOException: Couldn't lock lock file C:\TPNeo4jDB\lock because another process already holds the lock.

1> 节点操作

（1）节点：GraphDatabaseService().createNode()

（2）建立两个节点之间的关系：Node.createRelationShipTo(...)

（3）节点添加属性：Node.setProperty(name,value)  Neo4j中不允许null属性值

  （4）节点属性删除：Node.removeProperty(String propertyName)

2> 关系操作

（1）关系：RelationshipType()接口，DynamicRelationShipType()

（2）枚举类型：实现的接口

（3）关系添加属性：RelationShip.setProperty(String name, Object value)

（4）创建节点与节点之间的关系：node1.createRelationshipTo(node2,关系类型)

3> 标签

（1）接口Label()，可以通过枚举类型实现标签

（2）节点添加标签：Node.addLabel()

需要先将neo4j包中的Lib目录下所有的jar文件导入到eclipse

Native JAVA API详细代码：

p.p1 { margin: 0; font: 12px Menlo }
p.p2 { margin: 0; font: 12px Menlo; min-height: 14px }
p.p3 { margin: 0; font: 12px Menlo; color: rgba(63, 127, 95, 1) }
p.p4 { margin: 0; font: 12px Menlo; color: rgba(42, 0, 255, 1) }
span.s1 { color: rgba(127, 0, 85, 1) }
span.s2 { color: rgba(0, 0, 0, 1) }
span.s3 { color: rgba(106, 62, 62, 1) }
span.s4 { color: rgba(0, 0, 192, 1) }
span.s5 { color: rgba(42, 0, 255, 1) }
span.Apple-tab-span { white-space: pre }

package com.dwlm;

import java.io.File;

import org.neo4j.graphdb.GraphDatabaseService;

import org.neo4j.graphdb.Node;

import org.neo4j.graphdb.Relationship;

import org.neo4j.graphdb.Transaction;

import org.neo4j.graphdb.factory.GraphDatabaseFactory;

public class Neo4jNativeJavaApi {

//使用该方式Neo4j必须为停止状态

public static void main(String[] args) {

// 指定Neo4j数据存储路径

String dirName = "/Users/goboo/Library/neo4j-community-3.4.10/data/databases/graph.db";

File path = new File(dirName);

// 创建Neo4j数据库

GraphDatabaseFactory dbFactory = new GraphDatabaseFactory();

GraphDatabaseService db = dbFactory.newEmbeddedDatabase(path);

try (Transaction tx = db.beginTx()) {

// 进行数据库的操作

// 1.创建节点,同时要设置节点的标签

Node javaNode = db.createNode(Tutorials.JAVA);

Node scalaNode = db.createNode(Tutorials.SCALA);

// 2.设置节点属性

javaNode.setProperty("TutorialID", "JAVA001");

javaNode.setProperty("Title", "Learn Java");

javaNode.setProperty("NoOfChapters", "25");

javaNode.setProperty("Status", "Completed");

scalaNode.setProperty("TutorialID", "SCALA001");

scalaNode.setProperty("Title", "Learn Scala");

scalaNode.setProperty("NoOfChapters", "20");

scalaNode.setProperty("Status", "Completed");

// 3.创建关系，同时设置关系的标签

Relationship relationship = javaNode.createRelationshipTo(scalaNode, TutorialRelationships.JVM_LANGIAGES);

// 4.设置关系属性

relationship.setProperty("Id", "1234");

relationship.setProperty("OOPS", "YES");

relationship.setProperty("FP", "YES");

tx.success();

}

System.out.println("Done successfully");

}

}

Cypher Java API详细代码：

3. spring data Neo4j方式操作