一个完整的标准的cassandra连接代码（java版）

忘是亡心i 2022-06-15 05:11 238阅读 0赞

有个网友读了我前面几篇关于cassandra的文章后，向我反映，还不知道怎么安装cassandra呢，我一想也是啊，都没安装，怎么开始其他的呢，所以想安装顺序，从开始的开始讲。今天一个同事问我关于cassandra的java api，遂整理的此篇，可能有不完善的地方，敬请斧正。

需要引入的pom依赖：

<dependency>
    	<groupId>com.datastax.cassandra</groupId>
    	<artifactId>cassandra-driver-core</artifactId>
    	<version>3.1.1</version>
    </dependency>
    
    <dependency>
    	<groupId>com.datastax.cassandra</groupId>
    	<artifactId>cassandra-driver-extras</artifactId>
    	<version>3.1.1</version>
    </dependency>

String[] hosts = new String[]{"192.168.1.1", "192.168.1.2", "192.168.1.3"};//cassandra主机地址
    
            //认证配置
            AuthProvider authProvider = new PlainTextAuthProvider("ershixiong", "123456");
    
    
            LoadBalancingPolicy lbp = new TokenAwarePolicy(
                    DCAwareRoundRobinPolicy.builder().withLocalDc("myDC").build()
            );
    
            //读超时或连接超时设置
            SocketOptions so = new SocketOptions().setReadTimeoutMillis(3000).setConnectTimeoutMillis(3000);
    
            //连接池配置
            //PoolingOptions poolingOptions = new PoolingOptions().setConnectionsPerHost(HostDistance.LOCAL, 2, 3);
            //集群在同一个机房用HostDistance.LOCAL   不同的机房用HostDistance.REMOTE   忽略用HostDistance.IGNORED
            PoolingOptions poolingOptions= new PoolingOptions()
                    .setMaxRequestsPerConnection(HostDistance.LOCAL, 64)//每个连接最多允许64个并发请求
                    .setCoreConnectionsPerHost(HostDistance.LOCAL, 2)//和集群里的每个机器都至少有2个连接
                    .setMaxConnectionsPerHost(HostDistance.LOCAL, 6);//和集群里的每个机器都最多有6个连接
    
            //查询配置
            //设置一致性级别ANY(0),ONE(1),TWO(2),THREE(3),QUORUM(4),ALL(5),LOCAL_QUORUM(6),EACH_QUORUM(7),SERIAL(8),LOCAL_SERIAL(9),LOCAL_ONE(10);
            //可以在每次生成查询statement的时候设置，也可以像这样全局设置
            QueryOptions queryOptions = new QueryOptions().setConsistencyLevel(ConsistencyLevel.ONE);
    
            //重试策略
            RetryPolicy retryPolicy = DowngradingConsistencyRetryPolicy.INSTANCE;
    
            int port = 9042;//端口号
    
            String keyspace = "keyspacename";//要连接的库，可以不写
    
            Cluster cluster = Cluster.builder()
                    .addContactPoints(hosts)
                    .withAuthProvider(authProvider)
                    .withLoadBalancingPolicy(lbp)
                    .withSocketOptions(so)
                    .withPoolingOptions(poolingOptions)
                    .withQueryOptions(queryOptions)
                    .withRetryPolicy(retryPolicy)
                    .withPort(port)
                    .build();
            Session session = cluster.connect(keyspace);

参考：[http://docs.datastax.com/en/developer/java-driver-dse/1.2/upgrade\_guide/migrating\_from\_astyanax/queries\_and\_results/][http_docs.datastax.com_en_developer_java-driver-dse_1.2_upgrade_guide_migrating_from_astyanax_queries_and_results]

[http://zhaoyanblog.com/archives/547.html][http_zhaoyanblog.com_archives_547.html]

[http_docs.datastax.com_en_developer_java-driver-dse_1.2_upgrade_guide_migrating_from_astyanax_queries_and_results]: http://docs.datastax.com/en/developer/java-driver-dse/1.2/upgrade_guide/migrating_from_astyanax/queries_and_results/
[http_zhaoyanblog.com_archives_547.html]: http://zhaoyanblog.com/archives/547.html