Flink自定义序列化器

package org.hu.fk.ds_connector;

import com.ververica.cdc.connectors.shaded.org.apache.kafka.connect.data.Field;
import com.ververica.cdc.connectors.shaded.org.apache.kafka.connect.data.Schema;
import com.ververica.cdc.connectors.shaded.org.apache.kafka.connect.data.Struct;
import com.ververica.cdc.connectors.shaded.org.apache.kafka.connect.source.SourceRecord;
import com.ververica.cdc.debezium.DebeziumDeserializationSchema;
import io.debezium.data.Envelope;
import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.util.Collector;

import java.util.HashMap;
import java.util.Map;

//解析结果
//{after={id2=2, name2=b}, operation=READ}
// {before={id2=2, name2=b}, after={id2=2, name2=c}, operation=UPDATE}
// {before={id2=2, name2=c}, operation=DELETE}

//{"before":null,"after":{"id2":1,"name2":"a"},"source":{"version":"1.9.7.Final"
// ,"connector":"sqlserver","name":"sqlserver_transaction_log_source","ts_ms":0,"snapshot":"false"
// ,"db":"flinkcdc","sequence":null,"schema":"dbo","table":"c2","change_lsn":"80","commit_lsn":null,"event_serial_no":null}
// ,"op":"r","ts_ms":1718893242875,"transaction":null}
public class CustomDebeziumDeserializer implements DebeziumDeserializationSchema {
@Override
public void deserialize(SourceRecord sourceRecord, Collector collector) throws Exception {
Map<String, Object> parsedObject = new HashMap<>();

    // 注意，SourceRecord中并没有获取操作类型的方法。获取操作类型需要这么写
    Envelope.Operation operation = Envelope.operationFor(sourceRecord);
    parsedObject.put("operation", operation.toString());

    // topic返回的内容为：mysql_binlog_source.dbName.tableName，即数据源.数据库名.表名
    // 按照业务使用要求解析即可
    //{"before":null,"after":{"id2":1,"name2":"a"},
    // "source":{"version":"1.9.7.Final","connector":"mysql","name":"dbName.tableName","ts_ms":1675584339000,"

// if (null != sourceRecord.topic()) {
// String[] splitTopic = sourceRecord.topic().split("\.");
// if (splitTopic.length == 3) {
// parsedObject.put("database", splitTopic[1]);
// parsedObject.put("table", splitTopic[2]);
// }
// }

    // value返回sourceRecord中携带的数据，它是一个Struct类型
    // Struct的类型为org.apache.kafka.connect.data.Struct
    Struct value = (Struct) sourceRecord.value();
    // 变更前后的数据位于value这个Struct中，名称分别为before和after
    Struct before = value.getStruct("before");
    Struct after = value.getStruct("after");

    // 对于新增或删除的数据，before和after可能不存在，需要做null检查
    if (null != before) {
        Map<String, Object> beforeMap = new HashMap<>();
        // 获取Struct中包含所有字段名可以使用struct.schema().fields()方法，遍历即可
        Schema beforeSchema = before.schema();
        for (Field field : beforeSchema.fields()) {
            beforeMap.put(field.name(), before.get(field));
        }
        parsedObject.put("before", beforeMap);
    }

    if (null != after) {
        Map<String, Object> afterMap = new HashMap<>();
        Schema afterSchema = after.schema();
        for (Field field : afterSchema.fields()) {
            afterMap.put(field.name(), after.get(field));
        }

        parsedObject.put("after", afterMap);
    }

    Struct source = value.getStruct("source");
    if (null != source) {
        Map<String, Object> sourceMap = new HashMap<>();
        Schema sourceSchema = source.schema();
        for (Field field : sourceSchema.fields()) {
            sourceMap.put(field.name(), source.get(field));
        }
        parsedObject.put("source", sourceMap);
    }

// Struct op = value.getStruct("op");
// if (null != op) {
// Map<String, Object> afterMap = new HashMap<>();
// Schema afterSchema = op.schema();
// for (Field field : afterSchema.fields()) {
// afterMap.put(field.name(), after.get(field));
// }
//
// parsedObject.put("op", afterMap);
// }

    // 调用collector的collect方法，将转换后的数据发往下游
    collector.collect(parsedObject.toString());
}

@Override
public TypeInformation<String> getProducedType() {
    return BasicTypeInfo.STRING_TYPE_INFO;
}

}