Java 连接到在 docker 中运行的 cassandra

Question

我是 cassandra 的新手，和 docker 一样。我的目标是从 java 连接到在 docker 中运行的 cassandra。我在 Windows 机器上工作

我通过执行来运行 cassandra(也尝试了 ver 2.2、3.10 并且没有任何 env.variables)

docker run --name cassandra -d -e CASSANDRA_RPC_ADDRESS=127.0.0.1 cassandra:3.0

目前我有这样的 docker ps 输出:

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                                         NAMES

f932d3e7e0dc        cassandra:3.0       "/docker-entrypoin..."   5 seconds ago       Up 5 seconds        7000-7001/tcp, 7199/tcp, 9042/tcp, 9160/tcp   cassandra

我可以用这样的输出“docker exec -it cassandra cqlsh”

Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 3.0.13 | CQL spec 3.4.0 | Native protocol v4]

在java项目中我有gradle依赖

compile group: 'com.datastax.cassandra', name: 'cassandra-driver-core', version: '3.2.0'

我的测试代码(也尝试过不指定任何协议(protocol)版本，并尝试使用V5)

public static void main(String[] args)
{
  Cluster cluster = Cluster.builder()
                           .addContactPoint("127.0.0.1")
                           .withProtocolVersion(ProtocolVersion.V4)
                           .build();
  Session session = cluster.connect();
}

我得到这个异常:

Exception in thread "main" com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) tried for query failed (tried: /127.0.0.1:9042 (com.datastax.driver.core.exceptions.TransportException: [/127.0.0.1:9042] Cannot connect))
    at com.datastax.driver.core.ControlConnection.reconnectInternal(ControlConnection.java:232)
    at com.datastax.driver.core.ControlConnection.connect(ControlConnection.java:79)
    at com.datastax.driver.core.Cluster$Manager.negotiateProtocolVersionAndConnect(Cluster.java:1600)
    at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:1518)
    at com.datastax.driver.core.Cluster.init(Cluster.java:159)
    at com.datastax.driver.core.Cluster.connectAsync(Cluster.java:330)
    at com.datastax.driver.core.Cluster.connectAsync(Cluster.java:305)
    at com.datastax.driver.core.Cluster.connect(Cluster.java:247)
    at com.iter.cassandratest.Cassandratest.main(Cassandratest.java:17)

有什么想法我做错了吗？

编辑 1:

根据 dock I found，我刚刚尝试使用 -P 选项运行

现在 ps 输出是:

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                                                                                                                         NAMES

9eb54421aac2        cassandra:3.0       "/docker-entrypoin..."   4 seconds ago       Up 3 seconds        0.0.0.0:32772->7000/tcp, 0.0.0.0:32771->7001/tcp, 0.0.0.0:32770->7199/tcp, 0.0.0.0:32769->9042/tcp, 0.0.0.0:32768->9160/tcp   cassandra

我将代码更改为

Cluster cluster = Cluster.builder()
                             .addContactPoint("127.0.0.1")
                             .withPort(32769)
                             .withProtocolVersion(ProtocolVersion.V4)
                             .build();

异常改为

All host(s) tried for query failed (tried: /127.0.0.1:32769 (com.datastax.driver.core.exceptions.TransportException: [/127.0.0.1:32769]     
Channel has been closed)) 

Answer 1

如果您想使用默认端口连接到本地主机，您需要转发它。

docker run --name cassandra -d \
    -p 9042:9042 \
    cassandra:3.0

使用 -P 将根据 Dockerfile 的 EXPOSE 选项为您选择随机端口。