com.datastax.driver.core.OperationTimedOutException

Question

我使用Cassandra创建了以下测试类。

private static String server_ip = "127.0.0.1"; 
private static String keyspace = "hr"; 

private static Cluster cluster = null; 
private static Session session = null; 

public static void main (String [] args) 
{ 
    if(cluster!=null) return; 

    cluster = Cluster.builder().addContactPoints(server_ip).withPort(9042).build(); 


    final Metadata metadata = cluster.getMetadata(); 
    String msg = String.format("Connected to cluster: %s", metadata.getClusterName()); 
    System.out.println(msg); 

    System.out.println("List of hosts"); 
    for (final Host host : metadata.getAllHosts()) 
    { 
     msg = String.format("Datacenter: %s; Host: %s; Rack: %s", 
     host.getDatacenter(), 
     host.getAddress(), 
     host.getRack()); 
     System.out.println(msg); 
    } 
    session = cluster.connect(keyspace); 
} 

（Cluster.java:407） 在samples.SampleB.main（SampleB.java:28）

谷歌搜索后，我尝试没有成功，所有提出建议的解决方案。你能帮我解决这个问题吗？非常感谢。

Answer 1

你应该确认这些依赖关系：

<!-- Apache Cassandra Datastax's CQL driver. --> 
 
    
 
<dependency> 
 
    <groupId>com.datastax.cassandra</groupId> 
 
    <artifactId>cassandra-driver-core</artifactId> 
 
    <version>3.1.0</version> 
 
</dependency> 
 
    
 
<dependency> 
 
    <groupId>com.datastax.cassandra</groupId> 
 
    <artifactId>cassandra-driver-mapping</artifactId> 
 
    <version>3.1.0</version> 
 
</dependency>

HTH