flink kafka sink 默认分区器 FlinkFixedPartitioner 原理与注意_join_null的博客

FlinkFixedPartitioner源码：

package org.apache.flink.streaming.connectors.kafka.partitioner;
 
import org.apache.flink.util.Preconditions;
 
public class FlinkFixedPartitioner<T> extends FlinkKafkaPartitioner<T> {
    private int parallelInstanceId;
 
    public FlinkFixedPartitioner() {
    }
 
    public void open(int parallelInstanceId, int parallelInstances) {
        Preconditions.checkArgument(parallelInstanceId >= 0, "Id of this subtask cannot be negative.");
        Preconditions.checkArgument(parallelInstances > 0, "Number of subtasks must be larger than 0.");
        this.parallelInstanceId = parallelInstanceId;
    }
 
    public int partition(T record, byte[] key, byte[] value, String targetTopic, int[] partitions) {
        Preconditions.checkArgument(partitions != null && partitions.length > 0, "Partitions of the target topic is empty.");
        return partitions[this.parallelInstanceId % partitions.length];
    }
}package org.apache.f