Flink中不推荐使用JSONDeserializationSchema()吗? [英] is JSONDeserializationSchema() deprecated in Flink?

问题描述

我是Flink的新手，并且做的事情与下面的链接非常相​​似.

I am new to Flink and doing something very similar to the below link.

无法在下沉kafka流时看到消息，而在flink 1.2中看不到打印消息

我还试图将JSONDeserializationSchema()添加为我的没有密钥的Kafka输入JSON消息的反序列化器.

I am also trying to add JSONDeserializationSchema() as a deserializer for my Kafka input JSON message which is without a key.

但是我发现不存在JSONDeserializationSchema().

But I found JSONDeserializationSchema() is not present.

如果我做错了任何事情，请告诉我.

Please let me know if I am doing anything wrong.

推荐答案

JSONDeserializationSchema在之前已被弃用之后，已在Flink 1.8中删除.

JSONDeserializationSchema was removed in Flink 1.8, after having been deprecated earlier.

推荐的方法是编写一个实现DeserializationSchema<T>的解串器.这是一个示例，我已从

The recommended approach is to write a deserializer that implements DeserializationSchema<T>. Here's an example, which I've copied from the Flink Operations Playground:

import org.apache.flink.api.common.serialization.DeserializationSchema;
import org.apache.flink.api.common.typeinfo.TypeInformation;

import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;

/**
 * A Kafka {@link DeserializationSchema} to deserialize {@link ClickEvent}s from JSON.
 *
 */
public class ClickEventDeserializationSchema implements DeserializationSchema<ClickEvent> {

    private static final long serialVersionUID = 1L;

    private static final ObjectMapper objectMapper = new ObjectMapper();

    @Override
    public ClickEvent deserialize(byte[] message) throws IOException {
        return objectMapper.readValue(message, ClickEvent.class);
    }

    @Override
    public boolean isEndOfStream(ClickEvent nextElement) {
        return false;
    }

    @Override
    public TypeInformation<ClickEvent> getProducedType() {
        return TypeInformation.of(ClickEvent.class);
    }
}

对于Kafka制作人，您将要实现KafkaSerializationSchema<T>，并且您将在同一项目中找到该示例.

For a Kafka producer you'll want to implement KafkaSerializationSchema<T>, and you'll find examples of that in that same project.

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