Jsonld数据转入neo4j第三种代码案例Java的方式

以下是使用Java将Jsonld数据导入Neo4j的代码示例：

首先，需要使用Maven或Gradle等构建工具将以下依赖项添加到项目中：

<dependencies>
    <dependency>
        <groupId>org.neo4j.driver</groupId>
        <artifactId>neo4j-java-driver</artifactId>
        <version>4.1.1</version>
    </dependency>
    <dependency>
        <groupId>com.github.jsonld-java</groupId>
        <artifactId>jsonld-java</artifactId>
        <version>0.13.1</version>
    </dependency>
</dependencies>

然后，创建一个Java类来处理Jsonld数据并将其转换为Neo4j节点和关系：

import org.neo4j.driver.AuthTokens;
import org.neo4j.driver.Driver;
import org.neo4j.driver.GraphDatabase;
import org.neo4j.driver.Session;
import org.neo4j.driver.Transaction;
import org.neo4j.driver.TransactionWork;
import org.neo4j.driver.Value;
import org.neo4j.driver.types.Node;
import org.neo4j.driver.types.Relationship;
import org.neo4j.driver.types.TypeSystem;
import org.json.JSONObject;
import org.json.JSONArray;
import java.util.Map;

public class JsonldToNeo4j {

    private final Driver driver;

    public JsonldToNeo4j(String uri, String username, String password) {
        this.driver = GraphDatabase.driver(uri, AuthTokens.basic(username, password));
    }

    public void close() throws Exception {
        driver.close();
    }

    public void importJsonld(String jsonld) {
        try (Session session = driver.session()) {
            session.writeTransaction(new TransactionWork<Void>() {
                @Override
                public Void execute(Transaction tx) {
                    TypeSystem typeSystem = tx.typeSystem();
                    JSONObject jsonObject = new JSONObject(jsonld);
                    JSONArray jsonArray = jsonObject.getJSONArray("@graph");
                    for (int i = 0; i < jsonArray.length(); i++) {
                        JSONObject nodeObject = jsonArray.getJSONObject(i);
                        String id = nodeObject.getString("@id");
                        String type = nodeObject.getString("@type");
                        Map<String, Object> properties = nodeObject.toMap();
                        properties.remove("@id");
                        properties.remove("@type");
                        Node node = tx.createNode();
                        node.addLabel(typeSystem.label(type));
                        for (Map.Entry<String, Object> entry : properties.entrySet()) {
                            String key = entry.getKey();
                            Object value = entry.getValue();
                            if (value instanceof String) {
                                node.setProperty(key, (String) value);
                            } else if (value instanceof Integer) {
                                node.setProperty(key, (Integer) value);
                            } else if (value instanceof Double) {
                                node.setProperty(key, (Double) value);
                            }
                        }
                        JSONArray edgesArray = nodeObject.optJSONArray("edges");
                        if (edgesArray != null) {
                            for (int j = 0; j < edgesArray.length(); j++) {
                                JSONObject edgeObject = edgesArray.getJSONObject(j);
                                String edgeType = edgeObject.getString("@type");
                                String targetId = edgeObject.getString("@id");
                                Relationship relationship = node.createRelationshipTo(tx.getNodeById(Long.parseLong(targetId.substring(1))), typeSystem.relationshipType(edgeType));
                                Map<String, Object> edgeProperties = edgeObject.toMap();
                                edgeProperties.remove("@type");
                                edgeProperties.remove("@id");
                                for (Map.Entry<String, Object> entry : edgeProperties.entrySet()) {
                                    String key = entry.getKey();
                                    Object value = entry.getValue();
                                    if (value instanceof String) {
                                        relationship.setProperty(key, (String) value);
                                    } else if (value instanceof Integer) {
                                        relationship.setProperty(key, (Integer) value);
                                    } else if (value instanceof Double) {
                                        relationship.setProperty(key, (Double) value);
                                    }
                                }
                            }
                        }
                    }
                    return null;
                }
            });
        }
    }
}

最后，创建一个使用JsonldToNeo4j类的示例：

public class Main {

    public static void main(String[] args) throws Exception {
        JsonldToNeo4j importer = new JsonldToNeo4j("bolt://localhost:7687", "neo4j", "password");
        importer.importJsonld("{\n" +
                "  \"@context\": {\n" +
                "    \"name\": \"http://schema.org/name\",\n" +
                "    \"knows\": {\n" +
                "      \"@id\": \"http://xmlns.com/foaf/0.1/knows\",\n" +
                "      \"@type\": \"@id\"\n" +
                "    }\n" +
                "  },\n" +
                "  \"@graph\": [\n" +
                "    {\n" +
                "      \"@id\": \"http://example.org/alice\",\n" +
                "      \"@type\": \"http://schema.org/Person\",\n" +
                "      \"name\": \"Alice\",\n" +
                "      \"edges\": [\n" +
                "        {\n" +
                "          \"@type\": \"http://xmlns.com/foaf/0.1/knows\",\n" +
                "          \"@id\": \"_b\",\n" +
                "          \"name\": \"Bob\"\n" +
                "        }\n" +
                "      ]\n" +
                "    },\n" +
                "    {\n" +
                "      \"@id\": \"_b\",\n" +
                "      \"@type\": \"http://schema.org/Person\",\n" +
                "      \"name\": \"Bob\"\n" +
                "    }\n" +
                "  ]\n" +
                "}");
        importer.close();
    }
}

这将在Neo4j数据库中创建两个节点，一个代表Alice，另一个代表Bob，并且它们之间有一个“知道”关系。