使用Apache Avro对java.util.set字段进行序列化/反序列化

// 导入Avro相关的类
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericData;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.DatumReader;
import org.apache.avro.io.DatumWriter;
import org.apache.avro.io.Encoder;
import org.apache.avro.io.Decoder;
import org.apache.avro.io.EncoderFactory;
import org.apache.avro.io.DecoderFactory;
import org.apache.avro.reflect.ReflectData;
import org.apache.avro.specific.SpecificDatumReader;
import org.apache.avro.specific.SpecificDatumWriter;

import java.io.ByteArrayOutputStream;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;

// 定义一个示例的数据类
public class ExampleData {
    private Set<String> setField;

    public ExampleData() {
        setField = new HashSet<>();
    }

    public Set<String> getSetField() {
        return setField;
    }

    public void setSetField(Set<String> setField) {
        this.setField = setField;
    }
}

public class AvroExample {
    public static void main(String[] args) throws IOException {
        // 创建一个示例数据对象
        ExampleData data = new ExampleData();
        data.getSetField().add("Value 1");
        data.getSetField().add("Value 2");
        data.getSetField().add("Value 3");

        // 通过Avro的ReflectData获取Schema
        Schema schema = ReflectData.get().getSchema(ExampleData.class);

        // 创建一个GenericRecord对象来存储序列化的数据
        GenericRecord record = new GenericData.Record(schema);
        record.put("setField", data.getSetField());

        // 创建一个DatumWriter和Encoder来将数据序列化为字节数组
        DatumWriter<GenericRecord> writer = new SpecificDatumWriter<>(schema);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        Encoder encoder = EncoderFactory.get().binaryEncoder(out, null);
        writer.write(record, encoder);
        encoder.flush();

        byte[] serializedBytes = out.toByteArray();
        System.out.println("Serialized bytes: " + serializedBytes);

        // 创建一个DatumReader和Decoder来将字节数组反序列化为数据对象
        DatumReader<GenericRecord> reader = new SpecificDatumReader<>(schema);
        ByteArrayInputStream in = new ByteArrayInputStream(serializedBytes);
        Decoder decoder = DecoderFactory.get().binaryDecoder(in, null);
        GenericRecord deserializedRecord = reader.read(null, decoder);

        // 从反序列化的数据对象中获取Set字段值
        Set<String> deserializedSetField = (Set<String>) deserializedRecord.get("setField");
        System.out.println("Deserialized setField: " + deserializedSetField);
    }
}