如何使用neo4j-jdbc连接到Neo4j 3.0数据库？

Question

Hi,

I've created a maven project in eclipse and added the dependency:

<dependency>
    <groupId>org.neo4j</groupId>
    <artifactId>neo4j-jdbc</artifactId>
    <version>3.0</version>
</dependency>

I'm just trying to get a connection to my db working so that I can move on to integrate the connection with my main project but I'm having trouble getting things off the ground.

I've used the code example given on the official repo:

import org.neo4j.jdbc.Connection;
import org.neo4j.jdbc.PreparedStatement;
import org.neo4j.jdbc.ResultSet;

public class Neo4jConnectionTest {

    public static void main(String[] args) {
        // Connect
        Connection con = DriverManager.getConnection(
                                        "jdbc:neo4j:bolt://localhost");

        // Querying
        String query = "MATCH (u:User)-[:FRIEND]-(f:User) 
                        WHERE u.name = {1} 
                        RETURN f.name, f.age";
        try {
            PreparedStatement stmt = con.prepareStatement(query);
            stmt.setString(1,"John");
            ResultSet rs = con.execute();

            while (rs.next()) {
                System.out.println(
                    "Friend: "+rs.getString("f.name")+" is "+rs.getInt("f.age"));
            }
        } catch (Exception e) { e.printStackTrace(); }
        con.close();
    }
}

I am unable to compile this as:

DriverManager cannot be resolved within the neo4j-jdbc-3.0,

Prepared stmt = con.prepareStatement(query); causes a type mismatch,

and con.execute() is undefined for type org.neo4j.jdbc.Connection

I'd greatly appreciate any advice and expertise on the matter, thanks.

Answer 1

By changing to:

<dependency>
    <groupId>org.neo4j.driver</groupId>
    <artifactId>neo4j-java-driver</artifactId>
    <version>1.0.4</version>
</dependency>

I was able to successfully connect to the Neo4j 3.0 server using an example from Neo4j's site:

public static void main(String[] args) {
    Driver driver = GraphDatabase.driver( 
        "bolt://localhost", AuthTokens.basic( "neo4j", "neo4j" ) );
    Session session = driver.session();

    session.run( "CREATE (a:Person {name:'Arthur', title:'King'})" );

    StatementResult result = session.run( 
                                        "MATCH (a:Person) 
                                         WHERE a.name = 'Arthur' 
                                         RETURN a.name AS name, a.title AS title");

    while ( result.hasNext() ) {
        Record record = result.next();
        System.out.println( record.get( "title" ).asString() + 
                                " " + record.get("name").asString() );
    }

    session.close();
    driver.close();
}

I thought I'd share as this worked instantly with no hassle.

Neo4j Language Guides

Answer 2

DriverManager , Connection , PreparedStatement and ResultSet are all classes or interfaces from the java.sql package, which is part of the JDK. I guess the documentation assumes you'll use an IDE which will find the correct import for you.

It's the point of using the JDBC driver: you use the JDBC API, not a proprietary one (ie in a vendor package).

---

Update

There was a typo in the neo4j-jdbc readme, it should have read

ResultSet rs = stmt.execute();

instead of

ResultSet rs = con.execute();

otherwise the PreparedStatement has not use (and the code doesn't compile because there's no no-arg overload of Connection.execute() ).

---

Update 2

The documented dependency was also wrong, as neo4j-jdbc does not contain any driver.

You should depend on:

• either the all-in-one module, which gives you the opportunity to use the Bolt or HTTP protocols:

   <dependency> <groupId>org.neo4j</groupId> <artifactId>neo4j-jdbc-driver</artifactId> <version>3.0</version> </dependency> 

• or the module for a specific protocol:

   <dependency> <groupId>org.neo4j</groupId> <artifactId>neo4j-jdbc-bolt</artifactId> <version>3.0</version> </dependency> <!-- or --> <dependency> <groupId>org.neo4j</groupId> <artifactId>neo4j-jdbc-http</artifactId> <version>3.0</version> </dependency> 

---

Update 3

Both problems have now been fixed in the documentation of the project.