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-sdn
  mvc:
    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PathPatternMatcher
      matching-strategy: ant_path_matcher
  data:
    neo4j:
      database: neo4j
  neo4j:
    authentication:
      username: neo4j
      password: neo4j123
    uri: 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 {

    @Override
    public 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 {

    @Override
    public 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 {

    @Override
    public 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 {

    @Resource
    private AgencyRepository agencyRepository;

    @Test
    public void testFindByBid() {
        AgencyEntity agencyEntity = this.agencyRepository.findByBid(9001L);
        System.out.println(agencyEntity);
    }

    @Test
    public 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);
    }


    @Test
    public void testUpdate() {
        AgencyEntity agencyEntity = this.agencyRepository.findByBid(9001L);
        agencyEntity.setName("测试节点1");

        this.agencyRepository.save(agencyEntity);
        System.out.println(agencyEntity);
    }

    @Test
    public void testDeleteByBid() {
        Long count = this.agencyRepository.deleteByBid(9001L);
        System.out.println(count);
    }

    /**
     * 查询全部
     */
    @Test
    public void testFindAll() {
        List<AgencyEntity> list = this.agencyRepository.findAll();
        for (AgencyEntity agencyEntity : list) {
            System.out.println(agencyEntity);
        }
    }

    /**
     * 分页查询
     */
    @Test
    public 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：

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 {

    @Resource
    private Neo4jClient neo4jClient;

    @Override
    public 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 {

    @Resource
    private TransportLineRepository transportLineRepository;

    @Test
    void 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)
:::