🧶neo4j文档整理
1. 🛠环境部署方面
1.1 版本选择
对于neo4j版本方面，3.x 对应 Java8，4.x 对应 Java11。
现在87和88机器上使用的都是4.x版本。
1.2 部署
🐋docker中部署
拉取 neo4j 镜像，指定 7474，7687 端口的映射。
但是一定要指定import和data映射文件夹
🖥服务器直接部署
下载解压ce版本
更改/conf/neo4j.conf文件，之后启动 ./bin/neoj
# With default configuration Neo4j only accepts local connections.
# To accept non-local connections, uncomment this line:
#特别注意：默认是注释的，不开启，外网不能访问web端口neo4j
dbms.default_listen_address=0.0.0.0
# You can also choose a specific network interface, and configure a non-default
# port for each connector, by setting their individual listen_address.
# The address at which this server can be reached by its clients. This may be the server's IP address or DNS name, or
# it may be the address of a reverse proxy which sits in front of the server. This setting may be overridden for
# individual connectors below.
#dbms.default_advertised_address=localhost
# You can also choose a specific advertised hostname or IP address, and
# configure an advertised port for each connector, by setting their
# individual advertised_address.
# By default, encryption is turned off.
# To turn on encryption, an ssl policy for the connector needs to be configured
# Read more in SSL policy section in this file for how to define a SSL policy.
# Bolt connector
dbms.connector.bolt.enabled=true
#dbms.connector.bolt.tls_level=DISABLED
dbms.connector.bolt.listen_address=0.0.0.0:7687
#dbms.connector.bolt.advertised_address=:7687
# HTTP Connector. There can be zero or one HTTP connectors.
dbms.connector.http.enabled=true
dbms.connector.http.listen_address=0.0.0.0:7474
#dbms.connector.http.advertised_address=:7474
# HTTPS Connector. There can be zero or one HTTPS connectors.
dbms.connector.https.enabled=false
dbms.connector.https.listen_address=0.0.0.0:7473
#dbms.connector.https.advertised_address=:7473
2. ☕java开发方面
2.1 设置驱动启动
不推荐，推荐springboot的自动配置
//设置driver
Driver driver = GraphDatabase.driver("bolt://192.168.216.131:7687", AuthTokens.basic("neo4j", "123456" ));
//打开session
Session session = driver.session();
//执行语句
String cql = "create (n:Person{name:$name,title:$title})";
String insert_test_str = session.writeTransaction(new TransactionWork<String>() {
@Override
public String execute(Transaction tx) {
Result result = tx.run(cql,parameters("name","diomchen","title","The Code Hero"));
return "Create Node OK!";
}
});
//关闭session
session.close();
//关闭driver
driver.close();
2.2 springboot自动配置
#yml基本配置
neo4j:
uri: bolt://<host>:7687
username: neo4j
password: 123456
通过cypher语句实现操作
neo4j对象：
@Data
@Node(labels = {"Addresstxs"})
public class NAddresstxs {
// //自动生成id
// @Id @GeneratedValue
// private Long id;
//交易地址表Id
@Id
private String addresstxsId;
//交易地址
@Property(name ="address")
private String address;
repository：
@Repository
public interface AddresstxsRepository extends Neo4jRepository<NAddresstxs,String> {
@Query("create (n:Addresstxs{ addresstxsId:$addresstxsId , address:$address , type:$type}) return n")
List<NAddresstxs> addAddresstxs(@Param("addresstxsId") String addresstxsId, @Param("address") String address, @Param("type") Integer type);
@Query("match (n) return n")
List<NAddresstxs> getAddresstxs();
/*
特别需要注意返回的类型，否则会报以下问题
*/
}
org.springframework.data.mapping.MappingException: The schema already contains a node description under the primary label Addresstxs
cypher语句在 3.x 和 4.x 中有所不同
//java中cql(3.x)
String cql = "create (n:Person{name:{name},title:{title}})";
//java中cql(4.x)
String cql = "create (n:Person{name:$name,title:$title})";
通过Neo4jTemplate
pom:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-neo4j</artifactId>
</dependency>
注入:
@Resource
Neo4jTemplate neo4jTemplate;
其实和 MongoTemplate 操作一样，都是save，find等等，当然也支持自定条件。
3. 💾数据导入Neo4j数据库方面
导入数据到neo4j是最影响使用体验的。
3.1 导入方式比较
基本方式可以见下图，但是现在可用的只有create语句，load csv语句，apoc插件，其他的基本因为缺少维护而废用。
第一种 create 语句，可以说是非常之慢，实际使用远低于下图的1000/s速度。
第二种 load csv 语句，也是现在用的，3k+ 节点和12k+ 关系 导入花了 30 分钟左右 。
但是网上有创建约束的方法解决，也有通过添加**:auto using periodic commit 200** 控制提交频率的方式来提高导入速度，这些都还未尝试过。
最后一种 apoc 插件导入，还未使用，暂不做评价。
3.2 CSV数据创建和导入
📃CSV规范
Relationships规范
- START_ID
- END_ID
- TYPE
所以对于Node就需要有能够建立关系的标识性属性。
cypher 语句实际使用中，对于 TYPE 属性也并非硬性要求。
⛓CSV创建与导出
- java先从mongo中读取所需数据
- 创建导出csv所需属性的对象
- 利用fastjson插件，将对象列表转成json字符串
- 利用jackson插件，将json字符串转成csv
- 导出csv文件
工具类：
//对象列表转csv public static<T> void Object2Csv(List<T> objectList,String savePath) throws IOException { JSONArray jsonArray = new JSONArray(); jsonArray.addAll(objectList); String ss = jsonArray.toJSONString(); JsonNode jsonNode = new ObjectMapper().readTree(ss); CsvSchema.Builder csvSchemaBuild = CsvSchema.builder(); JsonNode fObject = jsonNode.elements().next(); fObject.fieldNames().forEachRemaining(fieldName -> {csvSchemaBuild.addColumn(fieldName);}); CsvSchema csvSchema = csvSchemaBuild.build().withHeader(); OutputStreamWriter ow = new OutputStreamWriter(new FileOutputStream(new File(savePath)),"gbk"); CsvMapper csvMapper = new CsvMapper(); csvMapper.writerFor(JsonNode.class) .with(csvSchema) .writeValue(ow, jsonNode); } //对象列表转json public static <T> void Object2Json(List<T> objectList,String savePath) throws IOException { JSONArray jsonArray = new JSONArray(); jsonArray.addAll(objectList); String ss = jsonArray.toJSONString(); save(ss,savePath); } private static void save(String jsonstr,String filename) throws IOException { OutputStreamWriter osw=new OutputStreamWriter(new FileOutputStream(filename), "gbk"); osw.write(jsonstr); osw.flush(); osw.close(); }
🧣CSV导入
只尝试过采用LOAD CSV语句的导出方式。
@Query("load csv with HEADERS from \"file:///addrN.csv\" as line merge (n:Address{address:line.address}) ") void optInAddAddressNode();
merge 的好处，它会判断库里面是否以及存在该相同节点，若有，则不会创建，反之，则会创建新节点。这样就避免了库里面存在多个重复节点。
参考资料：