SDN快速入门
Spring Data Neo4j简称SDN，是Spring对Neo4j数据库操作的封装，其底层基于neo4j-java-driver实现。
我们使用的版本为：6.2.3，官方文档：
下面我们将基于项目中的运输路线业务进行学习，例如：
:::info
【迪士尼营业部】-> 【浦东区转运中心】 -> 【上海转运中心】 -> 【北京转运中心】-> 【昌平区转运中心】-> 【金燕龙营业部】
:::
1、创建工程
创建工程，sl-express-sdn，导入依赖：
<?xml version="1.0" encoding="UTF-8"?>
<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><parent><groupId>com.sl-express</groupId><artifactId>sl-express-parent</artifactId><version>1.4</version></parent><groupId>com.sl-express.sdn</groupId><artifactId>sl-express-sdn</artifactId><version>1.0-SNAPSHOT</version><properties><maven.compiler.source>11</maven.compiler.source><maven.compiler.target>11</maven.compiler.target><sl-express-common.version>1.2-SNAPSHOT</sl-express-common.version></properties><dependencies><dependency><groupId>com.sl-express.common</groupId><artifactId>sl-express-common</artifactId><version>${sl-express-common.version}</version></dependency><!--SDN依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-neo4j</artifactId></dependency></dependencies></project>
2、编写配置文件
server:port: 9902
logging:level:org.springframework.data.neo4j: debug
spring:application:name: sl-express-sdnmvc:pathmatch:#解决异常：swagger Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException#因为Springfox使用的路径匹配是基于AntPathMatcher的，而Spring Boot 2.6.X使用的是PathPatternMatchermatching-strategy: ant_path_matcherdata:neo4j:database: neo4jneo4j:authentication:username: neo4jpassword: neo4j123uri: neo4j://192.168.150.101:7687
3、基础代码
3.1、SDNApplication
编写启动类：
package com.sl.sdn;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
public class SDNApplication {public static void main(String[] args) {SpringApplication.run(SDNApplication.class, args);}
}
3.2、Entity
编写实体，在物流中，会存在网点、二级转运中心、一级转运中心，我们分别用Agency、TLT、OLT表示。
由于以上三个机构的属性是相同的，但在Neo4j中的标签是不一样的，所以既要保证不同的类，也有相同的属性，这种场景比较适合将属性写到父类中，自己继承父类来实现，这里我们采用抽象类的来实现。
package com.sl.sdn.entity.node;import com.sl.sdn.enums.OrganTypeEnum;
import io.swagger.annotations.ApiModelProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.SuperBuilder;
import org.springframework.data.geo.Point;
import org.springframework.data.neo4j.core.schema.GeneratedValue;
import org.springframework.data.neo4j.core.schema.Id;@Data
@SuperBuilder(toBuilder = true)
@NoArgsConstructor
@AllArgsConstructor
public abstract class BaseEntity {@Id@GeneratedValue@ApiModelProperty(value = "Neo4j ID", hidden = true)private Long id;@ApiModelProperty(value = "业务id", required = true)private Long bid;@ApiModelProperty(value = "名称", required = true)private String name;@ApiModelProperty(value = "电话", required = true)private String phone;@ApiModelProperty(value = "地址", required = true)private String address;@ApiModelProperty(value = "位置坐标, x: 纬度，y: 经度", required = true)private Point location;//机构类型public abstract OrganTypeEnum getAgencyType();}机构枚举：
package com.sl.sdn.enums;import cn.hutool.core.util.EnumUtil;
import com.sl.transport.common.enums.BaseEnum;/*** 机构类型枚举*/
public enum OrganTypeEnum implements BaseEnum {OLT(1, "一级转运中心"),TLT(2, "二级转运中心"),AGENCY(3, "网点");/*** 类型编码*/private final Integer code;/*** 类型值*/private final String value;OrganTypeEnum(Integer code, String value) {this.code = code;this.value = value;}public Integer getCode() {return code;}public String getValue() {return value;}public static OrganTypeEnum codeOf(Integer code) {return EnumUtil.getBy(OrganTypeEnum::getCode, code);}
}package com.sl.sdn.entity.node;import com.sl.sdn.enums.OrganTypeEnum;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
import lombok.experimental.SuperBuilder;
import org.springframework.data.neo4j.core.schema.Node;/*** 网点实体*/
@Node("AGENCY")
@Data
@ToString(callSuper = true)
@SuperBuilder(toBuilder = true)
@NoArgsConstructor
public class AgencyEntity extends BaseEntity {@Overridepublic OrganTypeEnum getAgencyType() {return OrganTypeEnum.AGENCY;}
}package com.sl.sdn.entity.node;import com.sl.sdn.enums.OrganTypeEnum;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
import lombok.experimental.SuperBuilder;
import org.springframework.data.neo4j.core.schema.Node;/*** 一级转运中心实体 (OneLevelTransportEntity)*/
@Node("OLT")
@Data
@ToString(callSuper = true)
@SuperBuilder(toBuilder = true)
@NoArgsConstructor
public class OLTEntity extends BaseEntity {@Overridepublic OrganTypeEnum getAgencyType() {return OrganTypeEnum.OLT;}
}package com.sl.sdn.entity.node;import com.sl.sdn.enums.OrganTypeEnum;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
import lombok.experimental.SuperBuilder;
import org.springframework.data.neo4j.core.schema.Node;/*** 二级转运中心实体(TwoLevelTransportEntity)*/
@Node("TLT")
@Data
@ToString(callSuper = true)
@SuperBuilder(toBuilder = true)
@NoArgsConstructor
public class TLTEntity extends BaseEntity {@Overridepublic OrganTypeEnum getAgencyType() {return OrganTypeEnum.TLT;}
}package com.sl.sdn.entity.line;import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;/*** 运输路线实体*/
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class TransportLine {private Long id;private Double cost; //成本}3.3、DTO
DTO用于服务间的数据传输，会用到OrganDTO、TransportLineNodeDTO。
package com.sl.sdn.dto;import cn.hutool.core.annotation.Alias;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;import javax.validation.constraints.NotNull;/*** 机构数据对象，网点、一级转运、二级转运都是看作是机构* BaseEntity中的location无法序列化，需要将经纬度拆开封装对象*/
@Data
public class OrganDTO {@Alias("bid") //业务id作为id进行封装@ApiModelProperty(value = "机构id", required = true)private Long id;@ApiModelProperty(value = "名称", required = true)private String name;@ApiModelProperty(value = "类型，1:一级转运，2：二级转运，3:网点", required = true)private Integer type;@ApiModelProperty(value = "电话", required = true)private String phone;@ApiModelProperty(value = "地址", required = true)private String address;@ApiModelProperty(value = "纬度", required = true)private Double latitude;@ApiModelProperty(value = "经度", required = true)private Double longitude;}package com.sl.sdn.dto;import io.swagger.annotations.ApiModelProperty;
import lombok.Data;import java.util.ArrayList;
import java.util.List;/*** 运输路线对象*/
@Data
public class TransportLineNodeDTO {@ApiModelProperty(value = "节点列表", required = true)private List<OrganDTO> nodeList = new ArrayList<>();@ApiModelProperty(value = "路线成本", required = true)private Double cost = 0d;}4、Repository
SDN也是遵循了Spring Data JPA规范，同时也提供了Neo4jRepository，该接口中提供了基本的CRUD操作，我们定义Repository需要继承该接口。
4.1、AgencyRepository
package com.sl.sdn.repository;import com.sl.sdn.entity.node.AgencyEntity;
import org.springframework.data.neo4j.repository.Neo4jRepository;/*** 网点操作*/
public interface AgencyRepository extends Neo4jRepository<AgencyEntity, Long> {/*** 根据bid查询** @param bid 业务id* @return 网点数据*/AgencyEntity findByBid(Long bid);/*** 根据bid删除** @param bid 业务id* @return 删除的数据条数*/Long deleteByBid(Long bid);}测试：
package com.sl.sdn.repository;import com.sl.sdn.entity.node.AgencyEntity;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.*;import javax.annotation.Resource;
import java.util.List;@SpringBootTest
class AgencyRepositoryTest {@Resourceprivate AgencyRepository agencyRepository;@Testpublic void testFindByBid() {AgencyEntity agencyEntity = this.agencyRepository.findByBid(9001L);System.out.println(agencyEntity);}@Testpublic void testSave() {AgencyEntity agencyEntity = new AgencyEntity();agencyEntity.setAddress("测试数据地址");agencyEntity.setBid(9001L);agencyEntity.setName("测试节点");agencyEntity.setPhone("1388888888888");this.agencyRepository.save(agencyEntity);System.out.println(agencyEntity);}@Testpublic void testUpdate() {AgencyEntity agencyEntity = this.agencyRepository.findByBid(9001L);agencyEntity.setName("测试节点1");this.agencyRepository.save(agencyEntity);System.out.println(agencyEntity);}@Testpublic void testDeleteByBid() {Long count = this.agencyRepository.deleteByBid(9001L);System.out.println(count);}/*** 查询全部*/@Testpublic void testFindAll() {List<AgencyEntity> list = this.agencyRepository.findAll();for (AgencyEntity agencyEntity : list) {System.out.println(agencyEntity);}}/*** 分页查询*/@Testpublic void testPage() {//设置分页、排序条件，page从0开始PageRequest pageRequest = PageRequest.of(1, 2, Sort.by(Sort.Order.desc("bid")));Page<AgencyEntity> page = this.agencyRepository.findAll(pageRequest);page.getContent().forEach(agencyEntity -> {System.out.println(agencyEntity);});}}
4.2、JPA自定义方法规则
使用jpa中的规则，进行自定义查询：
| Keyword | Sample | Cypher snippet |
|---|---|---|
| After | findByLaunchDateAfter(Date date) | n.launchDate > date |
| Before | findByLaunchDateBefore(Date date) | n.launchDate < date |
| Containing (String) | findByNameContaining(String namePart) | n.name CONTAINS namePart |
| Containing (Collection) | findByEmailAddressesContains(Collection addresses) findByEmailAddressesContains(String address) | ANY(collectionFields IN [addresses] WHERE collectionFields in n.emailAddresses) ANY(collectionFields IN address WHERE collectionFields in n.emailAddresses) |
| In | findByNameIn(Iterable names) | n.name IN names |
| Between | findByScoreBetween(double min, double max) findByScoreBetween(Range range) | n.score >= min AND n.score <= max Depending on the Range definition n.score >= min AND n.score <= max or n.score > min AND n.score < max |
| StartingWith | findByNameStartingWith(String nameStart) | n.name STARTS WITH nameStart |
| EndingWith | findByNameEndingWith(String nameEnd) | n.name ENDS WITH nameEnd |
| Exists | findByNameExists() | EXISTS(n.name) |
| True | findByActivatedIsTrue() | n.activated = true |
| False | findByActivatedIsFalse() | NOT(n.activated = true) |
| Is | findByNameIs(String name) | n.name = name |
| NotNull | findByNameNotNull() | NOT(n.name IS NULL) |
| Null | findByNameNull() | n.name IS NULL |
| GreaterThan | findByScoreGreaterThan(double score) | n.score > score |
| GreaterThanEqual | findByScoreGreaterThanEqual(double score) | n.score >= score |
| LessThan | findByScoreLessThan(double score) | n.score < score |
| LessThanEqual | findByScoreLessThanEqual(double score) | n.score <= score |
| Like | findByNameLike(String name) | n.name =~ name |
| NotLike | findByNameNotLike(String name) | NOT(n.name =~ name) |
| Near | findByLocationNear(Distance distance, Point point) | distance( point(n),point({latitude:lat, longitude:lon}) ) < distance |
| Regex | findByNameRegex(String regex) | n.name =~ regex |
| And | findByNameAndDescription(String name, String description) | n.name = name AND n.description = description |
| Or | findByNameOrDescription(String name, String description) | n.name = name OR n.description = description (Cannot be used to OR nested properties) |
4.3、OLTRepository
package com.sl.sdn.repository;import com.sl.sdn.entity.node.OLTEntity;
import org.springframework.data.neo4j.repository.Neo4jRepository;/*** 一级转运中心数据操作*/
public interface OLTRepository extends Neo4jRepository<OLTEntity, Long> {/*** 根据bid查询** @param bid 业务id* @return 一级转运中心数据*/OLTEntity findByBid(Long bid);/*** 根据bid删除** @param bid 业务id* @return 删除的数据条数*/Long deleteByBid(Long bid);}4.4、OrganRepository
package com.sl.sdn.repository;import com.sl.sdn.dto.OrganDTO;import java.util.List;/*** 通用机构查询*/
public interface OrganRepository {/*** 无需指定type，根据id查询** @param bid 业务id* @return 机构数据*/OrganDTO findByBid(Long bid);/*** 查询所有的机构，如果name不为空的按照name模糊查询** @param name 机构名称* @return 机构列表*/List<OrganDTO> findAll(String name);
}4.5、TLTRepository
package com.sl.sdn.repository;import com.sl.sdn.entity.node.TLTEntity;
import org.springframework.data.neo4j.repository.Neo4jRepository;/*** 二级转运中心数据操作*/
public interface TLTRepository extends Neo4jRepository<TLTEntity, Long> {/*** 根据bid查询** @param bid 业务id* @return 二级转运中心数据*/TLTEntity findByBid(Long bid);/*** 根据bid删除** @param bid 业务id* @return 删除的数据条数*/Long deleteByBid(Long bid);}5、复杂查询
通过继承Neo4jRepository实现简单的查询是非常方便的，如果要实现复杂的查询就需要定义Cypher查询实现了，需要通过Neo4jClient进行查询操作，下面我们以查询两个网点间最短运输路线为例进行查询。
5.1、定义Repository
package com.sl.sdn.repository;import com.sl.sdn.dto.TransportLineNodeDTO;
import com.sl.sdn.entity.node.AgencyEntity;/*** 运输路线相关操作*/
public interface TransportLineRepository {/*** 查询两个网点之间最短的路线，查询深度为：10** @param start 开始网点* @param end 结束网点* @return 路线*/TransportLineNodeDTO findShortestPath(AgencyEntity start, AgencyEntity end);}5.2、编写实现
package com.sl.sdn.repository.impl;import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.convert.Convert;
import cn.hutool.core.util.NumberUtil;
import cn.hutool.core.util.StrUtil;
import com.sl.sdn.dto.OrganDTO;
import com.sl.sdn.dto.TransportLineNodeDTO;
import com.sl.sdn.entity.node.AgencyEntity;
import com.sl.sdn.enums.OrganTypeEnum;
import com.sl.sdn.repository.TransportLineRepository;
import org.neo4j.driver.internal.value.PathValue;
import org.neo4j.driver.types.Path;
import org.springframework.data.neo4j.core.Neo4jClient;
import org.springframework.data.neo4j.core.schema.Node;
import org.springframework.stereotype.Component;import javax.annotation.Resource;
import java.util.Map;
import java.util.Optional;@Component
public class TransportLineRepositoryImpl implements TransportLineRepository {@Resourceprivate Neo4jClient neo4jClient;@Overridepublic TransportLineNodeDTO findShortestPath(AgencyEntity start, AgencyEntity end) {//获取网点数据在Neo4j中的类型String type = AgencyEntity.class.getAnnotation(Node.class).value()[0];//构造查询语句String cypherQuery = StrUtil.format("MATCH path = shortestPath((start:{}) -[*..10]-> (end:{}))\n" +"WHERE start.bid = $startId AND end.bid = $endId \n" +"RETURN path", type, type);//执行查询Optional<TransportLineNodeDTO> optional = this.neo4jClient.query(cypherQuery).bind(start.getBid()).to("startId") //设置参数.bind(end.getBid()).to("endId")//设置参数.fetchAs(TransportLineNodeDTO.class) //设置响应数据类型.mappedBy((typeSystem, record) -> { //对结果进行封装处理PathValue pathValue = (PathValue) record.get(0);Path path = pathValue.asPath();TransportLineNodeDTO dto = new TransportLineNodeDTO();// 读取节点数据path.nodes().forEach(node -> {Map<String, Object> map = node.asMap();OrganDTO organDTO = BeanUtil.toBeanIgnoreError(map, OrganDTO.class);//取第一个标签作为类型organDTO.setType(OrganTypeEnum.valueOf(CollUtil.getFirst(node.labels())).getCode());//查询出来的数据，x：经度，y：纬度organDTO.setLatitude(BeanUtil.getProperty(map.get("location"), "y"));organDTO.setLongitude(BeanUtil.getProperty(map.get("location"), "x"));dto.getNodeList().add(organDTO);});//提取关系中的 cost 数据，进行求和计算，算出该路线的总成本path.relationships().forEach(relationship -> {Map<String, Object> objectMap = relationship.asMap();double cost = Convert.toDouble(objectMap.get("cost"), 0d);dto.setCost(NumberUtil.add(cost, dto.getCost().doubleValue()));});//取2位小数dto.setCost(NumberUtil.round(dto.getCost(), 2).doubleValue());return dto;}).one();return optional.orElse(null);}
}5.3、测试
编写测试用例：
package com.sl.sdn.repository;import com.sl.sdn.dto.TransportLineNodeDTO;
import com.sl.sdn.entity.node.AgencyEntity;
import com.sl.sdn.repository.TransportLineRepository;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import javax.annotation.Resource;import static org.junit.jupiter.api.Assertions.*;@SpringBootTest
class TransportLineRepositoryTest {@Resourceprivate TransportLineRepository transportLineRepository;@Testvoid findShortestPath() {AgencyEntity start = AgencyEntity.builder().bid(100280L).build();AgencyEntity end = AgencyEntity.builder().bid(210057L).build();TransportLineNodeDTO transportLineNodeDTO = this.transportLineRepository.findShortestPath(start, end);System.out.println(transportLineNodeDTO);}
}
测试结果：
:::tips
TransportLineNodeDTO(nodeList=[OrganDTO(id=100280, name=北京市昌平区定泗路, type=3, phone=010-86392987, address=北七家镇定泗路苍龙街交叉口, latitude=40.11765281246394, longitude=116.37212849638287), OrganDTO(id=90001, name=昌平区转运中心, type=2, phone=null, address=昌平区转运中心, latitude=40.220952, longitude=116.231034), OrganDTO(id=8001, name=北京市转运中心, type=1, phone=null, address=北京市转运中心, latitude=39.904179, longitude=116.407387), OrganDTO(id=8002, name=上海市转运中心, type=1, phone=null, address=上海市转运中心, latitude=31.230525, longitude=121.473667), OrganDTO(id=90003, name=浦东新区转运中心, type=2, phone=null, address=浦东新区转运中心, latitude=31.221461, longitude=121.544346), OrganDTO(id=210057, name=上海市浦东新区南汇, type=3, phone=18821179169, address=园春路8号, latitude=31.035240152911637, longitude=121.73459966751048)], cost=11577.8)
:::