Cypher SDK用法示例

环境准备

• 安装JDK 1.8以上版本。

• 安装maven。

代码示例

1. 创建并进入项目目录。

   mkdir cypher-java-example
   cd cypher-java-example

2. 创建pom.xml文件，内容如下。

   <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/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.gdb.alibaba</groupId>
     <artifactId>GdbGremlinExample</artifactId>
     <packaging>jar</packaging>
     <version>1.0-SNAPSHOT</version>
     <name>GdbGremlinExample</name>
     <url>http://maven.apache.org</url>
     <dependencies>
       <dependency>
          <groupId>org.neo4j.driver</groupId>
          <artifactId>neo4j-java-driver</artifactId>
          <version>4.0.1</version>
       </dependency>
     </dependencies>
     <build>
        <plugins>
           <plugin>
               <groupId>org.apache.maven.plugins</groupId>
               <artifactId>maven-compiler-plugin</artifactId>
               <version>2.0.2</version>
               <configuration>
                   <source>1.8</source>
                   <target>1.8</target>
               </configuration>
           </plugin>
           <plugin>
               <groupId>org.codehaus.mojo</groupId>
               <artifactId>exec-maven-plugin</artifactId>
               <version>1.3</version>
               <configuration>
                   <mainClass>com.example.gdb.HelloWorld</mainClass>
                   <complianceLevel>1.8</complianceLevel>
               </configuration>
           </plugin>
       </plugins>
     </build>
   </project>

3. 创建源码目录。

   mkdir -p src/main/java/com/example/gdb/

4. 编辑文件src/main/java/com/example/gdb/HelloWorld.java。其中GDB_HOST、GDB_PORT、GDB_USER、GDB_PASSWORD分别替换成对应实例的地址、端口、用户名和密码。

   package com.example.gdb;
   import org.neo4j.driver.AuthTokens;
   import org.neo4j.driver.Driver;
   import org.neo4j.driver.GraphDatabase;
   import org.neo4j.driver.Session;
   import org.neo4j.driver.Result;
   import org.neo4j.driver.Transaction;
   import org.neo4j.driver.TransactionWork;
   import static org.neo4j.driver.Values.parameters;
   public class HelloWorld implements AutoCloseable
   {
       private final Driver driver;
       public HelloWorld( 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 )
                   {
                       Result 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 ( HelloWorld greeter = new HelloWorld( "bolt://GDB_HOST:GDB_PORT", "GDB_USER", "GDB_PASSWORD" ) )
           {
               greeter.printGreeting( "hello" );
           }
       }
   }

5. 编译运行。

   mvn compile exec:java

   实例运行结果如下：

   hello, from node 1000010

环境准备

• 安装CPython 2.7或3.4以上，建议Python3。

• 安装pip。

• 安装neo4j driver。如果同时安装了多个版本的python和pip，需要用pip2或者pip3为指定版本安装。

  pip install neo4j --user

代码示例

1. 编辑文件cypher-python-example.py，内容如下。其中GDB_HOST、GDB_PORT、GDB_USER、GDB_PASSWORD分别替换成对应实例的地址、端口、用户名和密码。

   from neo4j import GraphDatabase
   class HelloWorldExample(object):
       def __init__(self, uri, user, password):
           self._driver = GraphDatabase.driver(uri,
                                               auth=(user, password),
                                               encrypted=False)
       def close(self):
           self._driver.close()
       def print_greeting(self, message):
           with self._driver.session() as session:
               greeting = session.write_transaction(
                   self._create_and_return_greeting, message)
               print(greeting)
       @staticmethod
       def _create_and_return_greeting(tx, message):
           result = tx.run(
               "CREATE (a:Greeting) "
               "SET a.message = $message "
               "RETURN a.message + ', from node ' + id(a)",
               message=message)
           return result.single()[0]
   e = HelloWorldExample('bolt://GDB_HOST:GDB_PORT', 'GDB_USER', 'GDB_PASSWORD')
   r = e.print_greeting('hello')

2. 编译运行。

   python cypher-python-example.py

   运行结果如下：

   hello, from node 1000003

环境准备

• 安装go 1.11以上。

• 安装seabolt。Neo4j go driver依赖于seabolt，推荐从源码编译安装。安装方法以Mac OS为例，其他安装方法参考seabolt的Github主页。

  # 安装openssl
  brew install openssl
  # 设置环境变量OPENSSL_ROOT_DIR
  export OPENSSL_ROOT_DIR=/usr/local/opt/openssl
  # 解压seabolt源码包
  tar zxvf seabolt-1.7.4.tar.gz
  cd seabolt-1.7.4
  mkdir build && cd build
  cmake ..
  make install

代码示例

1. 创建和初始化项目目录。

   mkdir cypher-go-example
   cd cypher-go-example
   go mod init cypher-go-example

2. 编辑main.go文件，内容如下。其中GDB_HOST、GDB_PORT、GDB_USER、GDB_PASSWORD分别替换成对应实例的地址、端口、用户名和密码。

   package main
   import (
       "fmt"
       "github.com/neo4j/neo4j-go-driver/neo4j"
   )
   func helloWorld(uri, username, password string) (string, error) {
       var (
           err      error
           driver   neo4j.Driver
           session  neo4j.Session
           result   neo4j.Result
           greeting interface{}
       )
       driver, err = neo4j.NewDriver(uri, neo4j.BasicAuth(username, password, ""))
       if err != nil {
           return "", err
       }
       defer driver.Close()
       session, err = driver.Session(neo4j.AccessModeWrite)
       if err != nil {
           return "", err
       }
       defer session.Close()
       greeting, err = session.WriteTransaction(func(transaction neo4j.Transaction) (interface{}, error) {
           result, err = transaction.Run(
               "CREATE (a:Greeting) SET a.message = $message RETURN a.message + ', from node ' + id(a)",
               map[string]interface{}{"message": "hello"})
           if err != nil {
               return nil, err
           }
           if result.Next() {
               return result.Record().GetByIndex(0), nil
           }
           return nil, result.Err()
       })
       if err != nil {
           return "", err
       }
       return greeting.(string), nil
   }
   func main() {
       greeting, err := helloWorld("bolt://GDB_HOST:GDB_PORT", "GDB_USER", "GDB_PORT")
       if err != nil {
           fmt.Println(err)
       }
       fmt.Println(string(greeting))
   }

3. 编译并运行示例，go会自动下载安装driver并添加依赖关系到go.mod文件中。

   go build ./.. && ./cypher-go-example
   # 或者
   go run main.go

   示例运行结果如下：

   hello, from node 1000004

代码示例

1. 创建项目，并进入项目目录。

   dotnet new console -o cypher-dotnet-example
   cd cypher-dotnet-example

2. 安装Neo4j.Driver。

   dotnet add package Neo4j.Driver.Simple

3. 编辑Program.cs，内容如下。其中GDB_HOST、GDB_PORT、GDB_USER、GDB_PASSWORD分别替换成对应实例的地址、端口、用户名和密码。

   using System;
   using System.Linq;
   using Neo4j.Driver;
   namespace cypherTest
   {
       public class HelloWorldExample : IDisposable
       {
           private readonly IDriver _driver;
           public HelloWorldExample(string uri, string user, string password)
           {
               _driver = GraphDatabase.Driver(uri, AuthTokens.Basic(user, password));
           }
           public void PrintGreeting(string message)
           {
               using (var session = _driver.Session())
               {
                   var greeting = session.WriteTransaction(tx =>
                   {
                       var result = tx.Run("CREATE (a:Greeting) " +
                                           "SET a.message = $message " +
                                           "RETURN a.message + ', from node ' + id(a)",
                           new {message});
                       return result.Single()[0].As<string>();
                   });
                   Console.WriteLine(greeting);
               }
           }
           public void Dispose()
           {
               _driver?.Dispose();
           }
           public static void Main()
           {
               using (var greeter = new HelloWorldExample("bolt://GDB_HOST:GDB_PORT", "GDB_USER", "GDB_PASSWORD"))
               {
                   greeter.PrintGreeting("hello");
               }
           }
       }
   }

4. 编译运行。

   dotnet run

   实例运行结果如下：

   hello, from node 1000007

代码示例

1. 新建并进入项目目录。

   mkdir cypher-js-example
   cd cypher-js-example

2. 添加Neo4j driver。

   npm install neo4j-driver

3. 编辑demo.js，内容如下。其中GDB_HOST、GDB_PORT、GDB_USER、GDB_PASSWORD分别替换成对应实例的地址、端口、用户名和密码。

   const neo4j = require("neo4j-driver");
   const driver = neo4j.driver('bolt://GDB_HOST:GDB_PORT',
                               neo4j.auth.basic('GDB_USER', 'GDB_PASSWORD'));
   async function helloWorld() {
     const session = driver.session();
     try {
       const result = await session.writeTransaction(
           tx => tx.run(
               'CREATE (a:Greeting) SET a.message = $message RETURN a.message + ", from node " + id(a)',
               {message : 'hello'}));
       const singleRecord = result.records[0];
       const greeting = singleRecord.get(0);
       return greeting;
     } finally {
       await session.close();
     }
   }
   helloWorld().then(msg => {
     console.log(msg);
     driver.close();
   });

4. 编译运行。

   node demo.js

   实例运行结果如下：

   hello, from node 1000008