阅读和使用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通过flink将数据读/写到cassandra中.我希望使用 flink-connector-cassandra ，我找不到该连接器的优质文档/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的接收器示例吗? apache flink是否也想从cassandra中读取数据，类似于apache spark?

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，这就是我想要的.我不知道它是否针对您的需要进行了简化，但我想我还是应该显示它.

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);

我发现问题的方法是感谢找到了"CassandraInputFormat"类的代码并查看了它的工作方式(

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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