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我正在使用 Neo4j 2.1.2 社区版。当我将 neo4j 指向我创建的数据库并登录到 webadmin 时，它显示了我在代码中创建的关系类型和标签，但是当我尝试获取节点和关系时，它没有列出任何东西。

请参阅随附的屏幕截图。在此处输入图像描述

我正在使用以下代码创建我的数据库。

import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Label;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;

public class HelloWorld {

private GraphDatabaseService m_databaseService;
private Node m_firstNode;
private Node m_secondNode;
private Relationship m_relationship;

public static void main(String[] args) {
    new HelloWorld().startApplication();
}

private void startApplication() {
    createDatabase();
    createNodesAndrelationship();
    shutDownDB();
}

private void createDatabase() {
    m_databaseService = new GraphDatabaseFactory().newEmbeddedDatabase("E:\\ERM\\RoutingData\\neo4j");
}

private void createNodesAndrelationship() {
    Transaction tx = m_databaseService.beginTx();

    try  {

        m_firstNode = m_databaseService.createNode();
        m_firstNode.addLabel(new Label() {

            @Override
            public String name() {
                return "Demo";
            }
        });
        m_firstNode.setProperty("message", "Hello");
        System.out.println("Created First Node.");

        m_secondNode = m_databaseService.createNode();
        m_secondNode.setProperty("message", "world !");
        m_secondNode.addLabel(new Label() {

            @Override
            public String name() {
                return "Demo";
            }
        });
        System.out.println("Created Second Node.");

        m_relationship = m_firstNode.createRelationshipTo(m_secondNode, RelType.KNOWS);
        m_relationship.setProperty("message", "bravo neo4j !");
        System.out.println("Created relationship.");

        tx.success();
    } finally {

        tx.failure();
    }

    System.out.println(m_firstNode.getProperty("message").toString() + " " + m_relationship.getProperty("message") + " " + m_secondNode.getProperty("message"));
}

private void shutDownDB() {
    m_databaseService.shutdown();
    System.out.println("Database shutdown completed.");
}

private static enum RelType implements RelationshipType {
    KNOWS
}

}

请建议我做错了什么。

4

1 回答 1

1

您正在回滚事务而不是提交事务。

替换tx.failure()为tx.close()。

此外，此行需要在tx.close()调用之前移动，以避免出现org.neo4j.graphdb.NotInTransactionException：

System.out.println(m_firstNode.getProperty("message").toString() + " " + m_relationship.getProperty("message") + " " + m_secondNode.getProperty("message"));
于 2014-09-15T22:31:57.963 回答