阅读&使用 apache flink Java API 将数据写入 cassandra [英] Read & write data into cassandra using apache flink Java API

问题描述

我打算使用 apache flink 使用 flink 将数据读/写到 cassandra 中.我希望使用 flink-connector-cassandra，我没有找到关于连接器的好的文档/示例.

I intend to use apache flink for read/write data into cassandra using flink. I was hoping to use flink-connector-cassandra, I don't find good documentation/examples for the connector.

能否请您指出使用 Apache Flink 从 cassandra 读取和写入数据的正确方法.我只看到纯粹用于写入的接收器示例?apache flink 是否也用于从类似于 apache spark 的 cassandra 读取数据?

Can you please point me to the right way for read and write data from cassandra using Apache Flink. I see only sink example which are purely for write ? Is apache flink meant for reading data too from cassandra similar to apache spark ?

推荐答案

我有同样的问题，这正是我要找的.我不知道它是否过于简化以满足您的需要，但我认为我仍然应该展示它.

I had the same question, and this is what I was looking for. I don't know if it is over simplified for what you need, but figured I should show it none the less.

ClusterBuilder cb = new ClusterBuilder() {
        @Override
        public Cluster buildCluster(Cluster.Builder builder) {
            return builder.addContactPoint("urlToUse.com").withPort(9042).build();
        }
    };

    CassandraInputFormat<Tuple2<String, String>> cassandraInputFormat = new CassandraInputFormat<>("SELECT * FROM example.cassandraconnectorexample", cb);

    cassandraInputFormat.configure(null);
    cassandraInputFormat.open(null);

    Tuple2<String, String> testOutputTuple = new Tuple2<>();
    cassandraInputFormat.nextRecord(testOutputTuple);

    System.out.println("column1: " + testOutputTuple.f0);
    System.out.println("column2: " + testOutputTuple.f1);

我发现这一点的方法是找到CassandraInputFormat"类的代码并了解它是如何工作的(http://www.javatips.net/api/flink-master/flink-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/batch/connectors/cassandra/Cas​​sandraInputFormat.java).老实说，我希望它只是一种格式，而不是基于名称的 Cassandra 的完整阅读课程，我觉得其他人可能也有同样的想法.

The way I figured this out was thanks to finding the code for the "CassandraInputFormat" class and seeing how it worked (http://www.javatips.net/api/flink-master/flink-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/batch/connectors/cassandra/CassandraInputFormat.java). I honestly expected it to just be a format and not the full class of reading from Cassandra based on the name, and I have a feeling others might be thinking the same thing.

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