来自FasterXML的ReadValue时Flink收集器问题 [英] Flink Collector Issue While ReadValue from FasterXML

问题描述

我将Kafka值设置为String，并将POJO设置如下，

I have Kafka values as String, and POJO as below,

{"name":"John","timeStamp":"2020-08-11T13:31:31"}

class Person{
    
    private String name;    

    private LocalDateTime timeStamp; 
}

此时间戳记是来自Kafka的String，并将其转换为LocalDateTime.

this Time Stamp comes as String from Kafka, and converting them into LocalDateTime.

当我使用FasterXML的所需库以独立模式和objectMapper.readValue(value, Person.class)身份运行程序时，它运行良好.正在转换.

When i run the program as Standalone and objectMapper.readValue(value, Person.class) using required library from FasterXML, it works fine. It's converting.

当我从Flink Framework阅读以下内容时，

When I read from Flink Framework with the below,

 stream.flatMap(new FlatMapFunction<String, Person>() {
            public void flatMap(String value, Collector<Person> out) {
                try {
                    out.collect(objectMapper.readValue(value, Person.class));
                } catch (JsonProcessingException e) {
                    e.printStackTrace();
                }
            }
        }).print();
        env.execute();

我遇到了以下问题，

Exception in thread "main" org.apache.flink.api.common.InvalidProgramException: com.fasterxml.jackson.databind.json.JsonMapper@1b7cc17c is not serializable. The object probably contains or references non serializable fields.

该消息显示我的Person对象不可序列化，并且我已经为Person类实现了Serializable，但是没有运气.而且，在下面尝试过，也不是很幸运.

The message shows me the Person object is not serializable, and i have implemented Serializable for Person class but no luck. And also, tried below, not luck too.

@JsonSerialize(using = LocalDateTimeSerializer.class)
private LocalDateTime timeStamp; 

更新:

类似于API的问题，我在下面的链接中阅读

Looks like issue with API, i read in the below link,

https://issues.apache.org/jira/browse/FLINK-12113

推荐答案

该异常指出JsonMapper实例不是Serializable-如果我没记错的话，它已从版本2.1开始可序列化. .另外，Person类也应设置为可序列化.

The exception states that the JsonMapper instance is not Serializable - if I'm not mistaken, it has been made serializable as of version 2.1. Also, Person class should be made serializable as well.

所以，在您的情况下，我会说您应该切换到jackson-databind版本>=2.1或可能将JsonMapper static字段设置为

So, in your case I would say you should either switch to jackson-databind version >=2.1 or probably make JsonMapper static field.

对于Person类，只需实现Serializable接口:

In case of Person class, just simply implement Serializable interface:

class Person implements Serializable {
    
    private String name;    

    private LocalDateTime timeStamp; 
}

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