我正在设立一个 P.O.C.使用 Neo4j，并且技术上拥有我需要工作但希望其设置正确的一切。
作为快速概述 - 我可以创建节点和关系，并遍历图表(即返回特定市场中可用的所有功能)，以便我知道这些节点/关系已创建。
但是，当我查询仅根据 ID 返回节点时，它仅返回该节点的数据 - 而不是任何关系或连接的节点，例如其可用的市场。
我在网上查看了很多地方，这些地方不仅返回了一个节点，而且还返回了后续节点 - 尽管我遵循他们正在做的事情，但我似乎无法让它与我的一起工作。
功能存储库:
@Repository
public interface FeatureRepository<T extends Feature> extends Neo4jRepository<T, Long> {
...
}
颜色存储库:
@Repository
public interface ColourRepository extends FeatureRepository<Colour>{
@Query("CREATE(feat:Colour:Feature {marketingDesc:{marketing}, engineeringDesc:{engineering}, code:{code}})")
Colour createColour(@Param("marketing") String marketingDesc, @Param("engineering") String engineeringDesc, @Param("code") String code);
@Query("MATCH (c:Colour {code:{colourCode}}) MATCH (c)-[:AVAILABLE_IN]->(market) RETURN c AS colour, COLLECT(market) AS markets")
Colour getColourByCode(@Param("colourCode") String colourCode);
Colour findByCode(@Param("code") String code);
}
功能实体:
@NodeEntity(label = "Feature")
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Feature {
@Id
@GeneratedValue
private Long id;
private String marketingDesc;
private String engineeringDesc;
@Index(unique = true)
private String code;
@Relationship(type = "HAS_OPTION", direction = Relationship.INCOMING)
private List<Option> options = new ArrayList<>();
@Relationship(type = "AVAILABLE_IN")
private List<Market> markets = new ArrayList<>();
@Relationship(type = "HAS_PREREQUISITE", direction = Relationship.UNDIRECTED)
private List<Prerequisite> prerequisites = new ArrayList<>();
}
颜色实体:
@AllArgsConstructor
@NodeEntity(label = "Colour")
public class Colour extends Feature {
}
市场实体:
@NodeEntity(label = "Market")
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Market {
@Id
@GeneratedValue
private Long id;
@Index(unique = true)
private String code;
private String market;
@Relationship(type = "AVAILABLE_IN", direction = Relationship.INCOMING)
private List<Option> features = new ArrayList<>();
}
关系实体(将功能连接到可以购买的市场):
@RelationshipEntity(type = "AVAILABLE_IN")
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Available {
@Id
@GeneratedValue
private Long Id;
private List<String> availableIn = new ArrayList<>();
@StartNode
private Feature feature;
@EndNode
private Market market;
}
Controller :
@RestController
public class ConfigController {
private final Handler configHandler;
public ConfigController(Handler configHandler) {
this.configHandler = configHandler;
}
@PostMapping(path = "/create/colour", consumes = APPLICATION_JSON_VALUE, produces = APPLICATION_JSON_VALUE)
public SimpleResponse createColour(@RequestBody Colour request) {
ColourService service = new ColourService(configHandler);
Colour created = service.createColour(request);
return SimpleResponse.builder().result("Created:", created).build();
}
@PostMapping(path = "/create/market", consumes = APPLICATION_JSON_VALUE, produces = APPLICATION_JSON_VALUE)
public SimpleResponse createMarket(@RequestBody Market request) {
MarketService service = new MarketService(configHandler);
Market created = service.createMarket(request);
return SimpleResponse.builder().result("Created", created).build();
}
@PostMapping(path = "/create/relationship/availableIn", consumes = APPLICATION_JSON_VALUE, produces = APPLICATION_JSON_VALUE)
public SimpleResponse createAvailableInRelationship(@RequestBody OptionAvailInRequest request){
RelationshipService service = new RelationshipService(configHandler);
Object result = service.createAvailableInRelationship(request);
return SimpleResponse.builder().result("Result:", result).build();
}
@GetMapping(path = "/colour/{code}")
public SimpleResponse getColourByCode(@PathVariable(value = "code") String code) {
ColourService service = new ColourService(configHandler);
Colour colour = service.getColourByCode(code);
return SimpleResponse.builder().result("Colour:", colour).build();
}
@GetMapping(path = "/features/available/{mrktCode}")
public SimpleResponse getFeaturesInMarket(@PathVariable(value = "mrktCode") String mrktCode){
RelationshipService service = new RelationshipService(configHandler);
Collection<Feature> features = service.getFeaturesInMarket(mrktCode);
return SimpleResponse.builder().result("Features:", features).build();
}
}
Neo4j配置文件:
@Configuration
@EnableNeo4jRepositories(basePackages = "package.location")
@EnableTransactionManagement
public class Neo4jConfig {
@Bean
public org.neo4j.ogm.config.Configuration configuration() {
org.neo4j.ogm.config.Configuration configuration =
new org.neo4j.ogm.config.Configuration.Builder().build();
return configuration;
}
@Bean
public SessionFactory sessionFactory(org.neo4j.ogm.config.Configuration configuration) {
return new SessionFactory(configuration,"package.location");
}
@Bean
public Neo4jTransactionManager transactionManager(SessionFactory sessionFactory) {
return new Neo4jTransactionManager(sessionFactory);
}
}
例如，在这里我可以创建一个颜色节点:
示例值:
{
"code": "string",
"engineeringDesc": "string",
"id": 0,
"marketingDesc": "string",
"markets": [
{
"code": "string",
"features": [
{}
],
"id": 0,
"market": "string"
}
],
"options": [
{}
],
"prerequisites": [
{}
]
}
我发送的内容:
{
"code": "BLU",
"engineeringDesc": "Blue engineering",
"marketingDesc": "Blue marketing"
}
这样就成功创建了一个颜色节点:
{
"result": {
"Created:": {
"id": 0,
"marketingDesc": "Blue marketing",
"engineeringDesc": "Blue engineering",
"code": "BLU",
"options": [],
"markets": [],
"prerequisites": []
}
},
"error": null
}
我可以创建一个市场节点: 示例值:
{
"code": "string",
"features": [
{}
],
"id": 0,
"market": "string"
}
我发送的内容:
{
"code": "UB",
"market": "England"
}
成功创建市场节点:
{
"result": {
"Created": {
"id": 1,
"code": "UB",
"market": "England",
"features": []
}
},
"error": null
}
然后我可以在两者之间创建关系，表示该颜色在该市场上可用:
{
"featureCode": "BLU",
"marketCode": "UB"
}
我可以通过点击以下命令来验证是否已创建: 本地主机:8080/features/available/UB
{
"result": {
"Features:": [
{
"id": 0,
"marketingDesc": "Blue marketing",
"engineeringDesc": "Blue engineering",
"code": "BLU",
"options": [],
"markets": [],
"prerequisites": []
}
]
},
"error": null
}
但是，当我返回颜色节点本身时: 本地主机:8080/颜色/BLU
{
"result": {
"Colour:": {
"id": 0,
"marketingDesc": "Blue marketing",
"engineeringDesc": "Blue engineering",
"code": "BLU",
"options": [],
"markets": [],
"prerequisites": []
}
},
"error": null
}
“市场”选项始终为空。我已经尝试过使用 Neo4j 帮助器(例如 findByCode 等)自定义查询和构建查询，我能找到的每个示例都会成功返回相关节点，但我似乎无法得到我的。
有人可以帮忙吗？ 附:如果还有其他内容对您有帮助，请告诉我。几天来一直试图解决这个问题......
最佳答案
找到了这个问题的答案...
功能实体应该是:
@Relationship(type = "AVAILABLE_IN")
@ApiModelProperty(hidden = true)
private Set<Available> markets = new HashSet<>();
市场实体应该是:
@Relationship(type = "AVAILABLE_IN", direction = Relationship.INCOMING)
@ApiModelProperty(hidden = true)
private Set<Available> features = new HashSet<>();
这使得 JSON 特征的市场部分不再为空...
现在我遇到的问题是，两个类之间存在无限递归循环，其中一个功能显示市场，而市场显示该功能
编辑:
对于遇到此/类似问题的其他人，我找到了一个非常好的 github 资源。 GitHub neo4j ogm walkthrough
帮助很大。
关于java - 从 neo4j 返回的 NodeEntity 不包含关系或连接的节点，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/56884660/