使用Golang操作Neo4j图数据库：neo4j-go-driver详解

Neo4j是一个流行的图数据库，而Golang社区提供了neo4j-go-driver库来方便地与Neo4j交互。下面我将详细介绍如何使用这个驱动库。

1. 安装驱动

首先安装neo4j-go-driver：

go get github.com/neo4j/neo4j-go-driver/v5

2. 基本连接与操作

2.1 建立连接

package main

import (
	"fmt"
	"log"

	"github.com/neo4j/neo4j-go-driver/v5/neo4j"
)

func main() {
	// Neo4j连接配置
	uri := "bolt://localhost:7687"
	username := "neo4j"
	password := "password"

	// 创建驱动
	driver, err := neo4j.NewDriver(uri, neo4j.BasicAuth(username, password, ""))
	if err != nil {
		log.Fatal(err)
	}
	defer driver.Close()

	// 获取会话
	session := driver.NewSession(neo4j.SessionConfig{AccessMode: neo4j.AccessModeWrite})
	defer session.Close()

	// 执行Cypher查询
	result, err := session.Run(
		"CREATE (n:Person {name: $name, age: $age}) RETURN n",
		map[string]interface{}{"name": "Alice", "age": 30},
	)
	if err != nil {
		log.Fatal(err)
	}

	// 处理结果
	if result.Next() {
		node := result.Record().Values[0].(neo4j.Node)
		fmt.Printf("Created node with ID: %d\n", node.Id)
	}
}

2.2 查询数据

func queryPersons(driver neo4j.Driver) {
	session := driver.NewSession(neo4j.SessionConfig{AccessMode: neo4j.AccessModeRead})
	defer session.Close()

	result, err := session.Run(
		"MATCH (p:Person) WHERE p.age > $age RETURN p.name, p.age",
		map[string]interface{}{"age": 25},
	)
	if err != nil {
		log.Fatal(err)
	}

	for result.Next() {
		record := result.Record()
		name, _ := record.Get("p.name")
		age, _ := record.Get("p.age")
		fmt.Printf("Name: %s, Age: %d\n", name, age)
	}
}

3. 高级操作

3.1 事务处理

func createFriendship(driver neo4j.Driver, person1, person2 string) error {
	session := driver.NewSession(neo4j.SessionConfig{})
	defer session.Close()

	_, err := session.WriteTransaction(func(tx neo4j.Transaction) (interface{}, error) {
		// 创建两个人和他们之间的关系
		_, err := tx.Run(
			"MERGE (a:Person {name: $name1}) "+
				"MERGE (b:Person {name: $name2}) "+
				"MERGE (a)-[:FRIEND]->(b)",
			map[string]interface{}{"name1": person1, "name2": person2},
		)
		return nil, err
	})
	return err
}

3.2 批量操作

func batchCreatePersons(driver neo4j.Driver, persons []map[string]interface{}) error {
	session := driver.NewSession(neo4j.SessionConfig{})
	defer session.Close()

	_, err := session.WriteTransaction(func(tx neo4j.Transaction) (interface{}, error) {
		for _, person := range persons {
			_, err := tx.Run(
				"CREATE (p:Person {name: $name, age: $age, city: $city})",
				person,
			)
			if err != nil {
				return nil, err
			}
		}
		return nil, nil
	})
	return err
}

4. 使用REST API

如果你确实需要使用REST API而不是Bolt协议，可以使用标准net/http包：

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
)

type Neo4jQuery struct {
	Statements []Statement `json:"statements"`
}

type Statement struct {
	Statement  string                 `json:"statement"`
	Parameters map[string]interface{} `json:"parameters,omitempty"`
}

func main() {
	url := "http://localhost:7474/db/neo4j/tx/commit"
	username := "neo4j"
	password := "password"

	query := Neo4jQuery{
		Statements: []Statement{
			{
				Statement: "MATCH (n:Person) RETURN n LIMIT 5",
			},
		},
	}

	jsonData, err := json.Marshal(query)
	if err != nil {
		fmt.Println(err)
		return
	}

	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		fmt.Println(err)
		return
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	req.SetBasicAuth(username, password)

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer resp.Body.Close()

	body, _ := ioutil.ReadAll(resp.Body)
	fmt.Println(string(body))
}

5. 最佳实践

1. 连接池管理：neo4j-go-driver内置了连接池，通常不需要手动管理
2. 参数化查询：总是使用参数化查询防止Cypher注入
3. 资源清理：确保关闭Session和Driver
4. 错误处理：正确处理所有可能的错误
5. 批量操作：对于大量数据，考虑使用UNWIND进行批量操作

6. 性能优化

// 使用UNWIND进行批量操作更高效
func batchCreateOptimized(driver neo4j.Driver, persons []map[string]interface{}) error {
	session := driver.NewSession(neo4j.SessionConfig{})
	defer session.Close()

	_, err := session.Run(
		"UNWIND $persons AS person "+
			"CREATE (p:Person) SET p = person",
		map[string]interface{}{"persons": persons},
	)
	return err
}

neo4j-go-driver提供了完整的Neo4j功能支持，建议优先使用Bolt协议而非REST API，因为性能更好。对于大多数应用场景，上述示例已经足够使用。