我对Neo4j很陌生,我想开始在Java应用程序中嵌入Neo4j。我尝试运行一个HelloWorld应用程序,如下所示。
import org.neo4j.driver.AuthTokens;
import org.neo4j.driver.Driver;
import org.neo4j.driver.GraphDatabase;
import org.neo4j.driver.Session;
import org.neo4j.driver.Result;
import org.neo4j.driver.Transaction;
import org.neo4j.driver.TransactionWork;
import static org.neo4j.driver.Values.parameters;
public class HelloWorldExample implements AutoCloseable
{
private final Driver driver;
public HelloWorldExample( String uri, String user, String password )
{
driver = GraphDatabase.driver( uri, AuthTokens.basic( user, password ) );
}
@Override
public void close() throws Exception
{
driver.close();
}
public void printGreeting( final String message )
{
try ( Session session = driver.session() )
{
String greeting = session.writeTransaction( new TransactionWork<String>()
{
@Override
public String execute( Transaction tx )
{
Result result = tx.run( "CREATE (a:Greeting) " +
"SET a.message = $message " +
"RETURN a.message + ', from node ' + id(a)",
parameters( "message", message ) );
return result.single().get( 0 ).asString();
}
} );
System.out.println( greeting );
}
}
public static void main( String... args ) throws Exception
{
try ( HelloWorldExample greeter = new HelloWorldExample( "bolt://localhost:7687", "neo4j", "password" ) )
{
greeter.printGreeting( "hello, world" );
}
}
}
Pom代码如下。
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.neo4j.driver</groupId>
<artifactId>neo4j-java-driver</artifactId>
<version>4.0.1</version>
<name>neo4jtest</name>
<build>
<plugins>
<plugin>
<groupId>1</groupId>
<artifactId>2</artifactId>
<version>3.2</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.neo4j</groupId>
<artifactId>neo4j-ogm-core</artifactId>
<version>3.1.2</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.neo4j</groupId>
<artifactId>neo4j-ogm-bolt-driver</artifactId>
<version>3.1.2</version>
<scope>runtime</scope>
</dependency>
</dependencies>
</dependencyManagement>
</project>
不幸的是,我无法运行这段代码,它引发了 "Exception in thread "main" java.lang.Error.未解决的编译问题:在HelloWorldExample.main(HelloWorldExample.java:46)"。Unresolved compilation problem: at HelloWorldExample.main(HelloWorldExample.java:46)"。此外,当我将鼠标悬停在导入行上时,我看到 "import org.neo4j cannot be resolved"。
谁能提供这方面的信息?
作为 有据可查为了使用 neo4j 的 Java 驱动程序,您需要指定相应的依赖关系。
<dependency>
<groupId>org.neo4j.driver</groupId>
<artifactId>neo4j-java-driver</artifactId>
<version>x.y.z</version>
</dependency>
最新的 发行版 是 4.0.1
.
[更新]
另外,你的 pom.xml
文件有很多其他问题。试试这样的例子吧。
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>helloworld</artifactId>
<version>1</version>
<name>neo4jtest</name>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.neo4j.driver</groupId>
<artifactId>neo4j-java-driver</artifactId>
<version>4.0.1</version>
</dependency>
</dependencies>
</project>
这个POM文件使用了一些虚拟的 groupId
, artifactId
和 version
的值(靠近顶部)。你应该用你自己的值来代替它们(不是属于neo4j的值)。