Gremlin+neo4j+完整实例
一. 简介
关于Gremlin和neo4j的简介这里不做过多的介绍，目前两者主要是解决数据血缘的问题，本文主要讲解内嵌型Gremlin和neo4j的使用方式以及完整的实例。
二. 版本适配
Gremlin和neo4j都是用java开发的所以也都是依赖jvm的，这才能够完全内嵌到我们的java程序中，于我们的java程序共用一个jvm，但是当要存的数据量过大时，就会产生一些数据库于程序在jvm的平衡还有jvm的压力等各种问题，本文不深究于此，下面我们看两者的版本
// embedded graph of gremlin and driver
implementation 'org.apache.tinkerpop:gremlin-core:3.4.10'
implementation 'org.apache.tinkerpop:gremlin-driver:3.4.10'
// embedded neo4j and tinkerpop api impl
implementation 'org.apache.tinkerpop:neo4j-gremlin:3.4.10'
implementation 'org.neo4j:neo4j-tinkerpop-api-impl:0.9-3.4.0'目前为止neo4j对gremlin兼容的最高版本为3.4.0（更高的版本不兼容难道是他想搞自己的标准？）
三.使用
1. 启动Gremlin
我们选择在springboot项目启动后，加载neo4jGraph的实例，当然也可以在用的时候加载，但是这个实例只能加载一次，不然会报错。
import org.apache.tinkerpop.gremlin.neo4j.structure.Neo4jGraph;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;/*** Construct a graph instance by specifying the directory to create the database.*/
@Component
@Order(1)
public class DataBaseApplicationRunner implements ApplicationRunner {private String graphDataSource = "/tmp/neo4j";private Neo4jGraph graph;@Overridepublic void run(ApplicationArguments args) {// 启动时可以注入neo4j数据保存的位置log.info("Graph database loading.....");String[] sourceArgs = args.getSourceArgs();if (sourceArgs.length >= 1) {graphDataSource = sourceArgs[0];}try {graph = Neo4jGraph.open(graphDataSource);} catch (Exception e) {GraphLog.log.error("Graph database load happen Exception.", e);}log.info("Graph database load success.");}public Neo4jGraph getGraph() {return graph;}
}
2. Graph Access
我们设计与Gremlin交互的并自动释放资源的工具类
@Component
public final class GraphAccess {private static DataBaseApplicationRunner dataBaseApplicationRunner;@Autowiredpublic void setGraphApplication(DataBaseApplicationRunner dataBaseApplicationRunner) {GraphAccess.dataBaseApplicationRunner = dataBaseApplicationRunner;}// 获取gremlin连接public static GraphTraversalSource getGraphTraversalSource() {GraphTraversalSource g = traversal().withEmbedded(dataBaseApplicationRunner.getGraph());g.tx().onReadWrite(Transaction.READ_WRITE_BEHAVIOR.AUTO);return g;}// set节点并返回这个节点，自动释放连接public static Vertex exec(GraphVertexSupplier graphVertexSupplier) {try (GraphTraversalSource g = getGraphTraversalSource()) {try {return graphVertexSupplier.exec();} catch (Exception e) {GraphLog.log.error("graph database operation happen Exception.", e);g.tx().rollback();close(g);throw e;} finally {g.tx().close();}}}/*** graph database operation that return list and auto close** @param graphGetOperation GraphSourceToList* @return List相关FunctionInterface：
@FunctionalInterface
public interface GraphSourceToList {List exec(GraphTraversalSource graphTraversalSource);
}
@FunctionalInterface
public interface GraphSourceConsumer {void exec(GraphTraversalSource graphTraversalSource);
}
@FunctionalInterface
public interface GraphVertexSupplier {Vertex exec();
}
@FunctionalInterface
public interface GraphOperation {void exec();
}@FunctionalInterface
public interface GraphEdgeSupplier {Edge exec();
}
@FunctionalInterface
public interface GraphTraversalSupplier {GraphTraversal exec();
}
3. Dao层
3.1. put Dao
@Component
public class GraphPutDao {// set vertexpublic Vertex setVertex(String label, Map property) {return GraphAccess.use((GraphVertexSupplier) (g) -> {GraphTraversal traversal = g.addV(label);addVertexProperty(traversal, property);return traversal.next();});}// set edgepublic void setEdge( EachGraphDomain eachGraphDomain) {GraphAccess.use((g) -> {GraphTraversal traversal = g.addE(eachGraphDomain.getEdgeLabel()).from(eachGraphDomain.getStartVertex());addEdgeProperty(traversal, eachGraphDomain.getEdgeProperty());traversal.to(eachGraphDomain.getEndVertex()).iterate();});}private void addVertexProperty(GraphTraversal graphTraversal, Map properties) {properties.forEach(graphTraversal::property);}private void addEdgeProperty(GraphTraversal graphTraversal, Map properties) {properties.forEach(graphTraversal::property);}
} 3.2. Get Dao
@Component
public class GraphGetDao {/*** @param label String* @return List*/public List getVertexByLabel(String label) {return GraphAccess.use((GraphSourceToList) g -> g.V().hasLabel(label).toList());}/*** @param sId String* @param eId String* @return List 4. 调用
public class Test {GraphGetDao getDao = new GaraphGetDao();GraphPutDao putDao = new GaraphPutDao();Vertex startVertex = putDao.setVertex("startlable", Map.of("name", "zhangsan", "age", "23"));Vertex endVertex = putDao.setVertex("endlable", Map.of("name", "lisi", "age", "24"));putDao .setEdge(startVertex, endVertex, "edge", Map.of("relation", "brother");getDao.getVertexByLabel("startlable");getDao.getIndegreeVertex("endlable");getDao.getOutdegreeVertex("startLable");
}5. 其他工具类
@Getter
@AllArgsConstructor
public class EachGraphDomain {private final Vertex startVertex;private final Vertex endVertex;private final String edgeLabel;private final Map edgeProperty;
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