1. writetest: 根据 schema 把数据写到一个 file container
2. readtest: 打开 file container，将其中的数据 print 出来
package kcode.avro.java;
import java.io.File;
import java.io.IOException;
import org.apache.avro.Schema;
import org.apache.avro.file.DataFileWriter;
import org.apache.avro.file.DataFileReader;
import org.apache.avro.generic.GenericData;
import org.apache.avro.generic.GenericDatumWriter;
import org.apache.avro.generic.GenericDatumReader;
class HelloAvro {
static private void appendPerson(DataFileWriter<GenericData.Record> writer,
Schema aSchema, long id, String name) throws IOException {
GenericData.Record aPerson = new GenericData.Record(aSchema);
aPerson.put("ID", id);
aPerson.put("Name", name);
writer.append(aPerson);
}
static private void writeTest() throws IOException {
Schema aSchema = Schema.parse(new File("decl/Person.json"));
DataFileWriter<GenericData.Record> writer = new DataFileWriter<GenericData.Record>(
new GenericDatumWriter<GenericData.Record>());
writer.create(aSchema, new File("output/Person.db"));
appendPerson(writer, aSchema, 1001, "kasicass");
appendPerson(writer, aSchema, 1002, "phay");
writer.close();
}
static private void printPerson(GenericData.Record aPerson) {
System.out.println("aPerson, id=" + aPerson.get("ID") + ", name=" + aPerson.get("Name"));
}
static private void readTest() throws IOException {
DataFileReader<GenericData.Record> reader = new DataFileReader<GenericData.Record>(new File("output/Person.db"),
new GenericDatumReader<GenericData.Record>());
while (reader.hasNext()) {
GenericData.Record aPerson = reader.next();
printPerson(aPerson);
}
}
static public void main(String[] args) throws IOException {
if (args.length != 1) {
System.out.println("usage:");
System.out.println(" ./a.out <readtest|writetest>");
return;
}
if (args[0].equals("readtest")) {
readTest();
} else {
writeTest();
}
}
}
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