cassandra - 从 com.example.cassandra 使用 Java Driver for Apache Cassandra 1.0 连接到 Cassandra 时出错

Question

通过 DataStax 使用 Cannsandra 的 Java 驱动程序连接到 Cassandra 客户端时，它抛出以下错误..

线程“main”com.datastax.driver.core.exceptions.NoHostAvailableException 中的异常:所有主机尝试查询失败(尝试:[/127.0.0.1])

请建议...

谢谢!

我的java代码是这样的:

package com.example.cassandra;

import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Host;
import com.datastax.driver.core.Metadata;

public class SimpleClient {

private Cluster cluster;

public void connect(String node){

    cluster = Cluster.builder().addContactPoint(node).build();
    Metadata metadata = cluster.getMetadata();
    System.out.println(metadata.getClusterName());
}   


public void close()
{
cluster.shutdown();
}

public static void main(String args[]) {

SimpleClient client = new SimpleClient();
client.connect("127.0.0.1");
client.close();
}

Answer 1

就我而言，我遇到了这个问题，因为我在连接期间使用了默认的 RPC 端口 9160。可以在 cassandra.yaml 中找到 CQL 的不同端口 -

start_native_transport: true
# port for the CQL native transport to listen for clients on
native_transport_port: 9042

一旦我将代码更改为使用端口 9042，连接尝试就成功了 -

public BinaryDriverTest(String cassandraHost, int cassandraPort, String keyspaceName) {
    m_cassandraHost = cassandraHost;
    m_cassandraPort = cassandraPort;
    m_keyspaceName = keyspaceName;

    LOG.info("Connecting to {}:{}...", cassandraHost, cassandraPort);
    cluster = Cluster.builder().withPort(m_cassandraPort).addContactPoint(cassandraHost).build();
    session = cluster.connect(m_keyspaceName);
    LOG.info("Connected.");
}

public static void main(String[] args) {
    BinaryDriverTest bdt = new BinaryDriverTest("127.0.0.1", 9042, "Tutorial");
}