java - 通用数据记录无法转换为 Avro

Question

我最近运行了一个 Sqoop 作业，然后使用 AvroTools 提取 avro 文件的模式，然后将其编译成一个 Java 类。每当我尝试使用 Avro 对象时，我都会收到以下 ClassCastException:

java.lang.Exception: java.lang.ClassCastException: org.apache.avro.generic.GenericData$Record cannot be cast to com.xxx.xxx.patient_avro.PatientAvro at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462) at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:522) Caused by: java.lang.ClassCastException: org.apache.avro.generic.GenericData$Record cannot be cast to com.xxx.xxx.patient_avro.PatientAvro at com.xxx.xxx.knn_mapreduce.KNNMapper.map(KNNMapper.java:28) at com.xxx.xxx.knn_mapreduce.KNNMapper.map(KNNMapper.java:14) at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:146) at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:787) at org.apache.hadoop. mapred.MapTask.run(MapTask.java:341)

我的映射器:

public class KNNMapper extends Mapper<AvroKey<PatientAvro>, NullWritable, LongWritable, PatientWritable> {

PatientWritable patient;
LongWritable providerKey;
Integer patientKey;
Integer lengthOfStay;
Integer msDrgGroup;
Integer age;

@Override
public void map(AvroKey<PatientAvro> patientAvro, NullWritable value, Context context) throws IOException, InterruptedException {



    patientKey = patientAvro.datum().getPatientKey();
    lengthOfStay = patientAvro.datum().getLengthOfStay();
    msDrgGroup = patientAvro.datum().getMsDrg();
    age = patientAvro.datum().getAge();
    patient = new PatientWritable();
    patient.set(new Long(patientKey), new Double((double) lengthOfStay), new Double((double) msDrgGroup), new Double((double)age));

    providerKey = new LongWritable(patientAvro.datum().getProviderKey());
    context.write(providerKey, patient);
}
}

如有任何帮助，我们将不胜感激。

Answer 1

Sqoop 自动创建 Java 和 .avsc 文件。您是单独创建它们吗？因此，如果您只使用生成的 Java，应该没问题。