1.与上篇类似，只是代码改下：
package org.apache.spark.avro.learning
import java.io.File
import java.text.SimpleDateFormat
import java.util.Date
import org.apache.avro.Schema
import org.apache.avro.file.DataFileReader
import org.apache.avro.file.DataFileWriter
import org.apache.avro.generic.GenericData
import org.apache.avro.generic.GenericDatumReader
import org.apache.avro.generic.GenericDatumWriter
import org.apache.avro.generic.GenericRecord
object AvroNoCode {
def main(args: Array[String]): Unit = {
val schema = new Schema.Parser().parse(new File(
"file/data/avro/input/user.avsc"));
val user1 = new GenericData.Record(schema);
println(user1);
user1.put("name", "Alyssa");
user1.put("favorite_number", 256);
val user2 = new GenericData.Record(schema);
user2.put("name", "Ben");
user2.put("favorite_number", 7);
user2.put("favorite_color", "red");
println("create user:");
println(user1);
println(user2);
// Serialize user1 and user2 to disk
val iString = new SimpleDateFormat("yyyyMMddHHmmssSSS")
.format(new Date());
val file = new File("file/data/avro/output/users" + iString + ".avro");
val datumWriter = new GenericDatumWriter[GenericRecord] (
schema);
val dataFileWriter = new DataFileWriter[GenericRecord] (
datumWriter);
dataFileWriter.create(schema, file);
dataFileWriter.append(user1);
dataFileWriter.append(user2);
dataFileWriter.close();
// Deserialize users from disk
val datumReader = new GenericDatumReader[GenericRecord] (
schema);
val dataFileReader = new DataFileReader[GenericRecord] (
file, datumReader);
;
var user = null:GenericRecord;
while (dataFileReader.hasNext()) {
// Reuse user object by passing it to next(). This saves us from
// allocating and garbage collecting many objects for files with
// many items.
user = dataFileReader.next(user);
println(user);
}
println("end");
}
}
2.运行结果：
{"name": null, "favorite_number": null, "favorite_color": null}
create user:
{"name": "Alyssa", "favorite_number": 256, "favorite_color": null}
{"name": "Ben", "favorite_number": 7, "favorite_color": "red"}
{"name": "Alyssa", "favorite_number": 256, "favorite_color": null}
{"name": "Ben", "favorite_number": 7, "favorite_color": "red"}
end 文件：
Objavro.schema�{"type":"record","name":"User","namespace":"example.avro","fields":[{"name":"name","type":"string"},{"name":"favorite_number","type":["int","null"]},{"name":"favorite_color","type":["string","null"]}]}
