将字节数组转换为Json并给出avro模式作为输入将给出错误 [英] Converting byte array to Json giving avro Schema as input is giving an error
问题描述
我有一个简单的JSON
I have a simple JSON
String jsonPayload = "{\"empid\": \"6\",\"empname\": \"Saurabh\",\"address\": \"home\"}";
jsonPayload.getBytes();
我创建了Avro模式
{"namespace": "sample.namespace",
"type": "record",
"name": "Employee",
"fields": [
{"name": "empid", "type": "string"},
{"name": "empname", "type": "string"},
{"name": "address", "type": "string"}
]
}
当我尝试比较它们时,我得到一个错误 例外:
When I try to compare them I get an error Exception :
org.apache.avro.AvroRuntimeException: Malformed data. Length is negative: -62
at org.apache.avro.io.BinaryDecoder.doReadBytes(BinaryDecoder.java:336)
at org.apache.avro.io.BinaryDecoder.readString(BinaryDecoder.java:263)
at org.apache.avro.io.ResolvingDecoder.readString(ResolvingDecoder.java:201)
at org.apache.avro.generic.GenericDatumReader.readString(GenericDatumReader.java:430)
at org.apache.avro.generic.GenericDatumReader.readString(GenericDatumReader.java:422)
at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:180)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:152)
at org.apache.avro.generic.GenericDatumReader.readField(GenericDatumReader.java:240)
at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:230)
at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:174)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:152)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:144)
看起来像String和Charsequence标识有问题.无法确定确切的问题
Looks like there is problem with String and Charsequence identification. Not able to identify exact problem
bytearraytojson转换器方法代码
bytearraytojson converter method code
public String byteArrayToJson(byte[] avro, Schema schema) throws IOException {
boolean pretty = false;
GenericDatumReader<GenericRecord> reader = null;
JsonEncoder encoder = null;
ByteArrayOutputStream output = null;
try {
reader = new GenericDatumReader<GenericRecord>(schema);
InputStream input = new ByteArrayInputStream(avro);
output = new ByteArrayOutputStream();
DatumWriter<GenericRecord> writer = new GenericDatumWriter<GenericRecord>(schema);
encoder = EncoderFactory.get().jsonEncoder(schema, output, pretty);
Decoder decoder = DecoderFactory.get().binaryDecoder(input, null);
GenericRecord datum;
while (true) {
try {
datum = reader.read(null, decoder);
} catch (EOFException eofe) {
break;
}
writer.write(datum, encoder);
}
encoder.flush();
output.flush();
return new String(output.toByteArray());
} finally {
try {
if (output != null) output.close();
} catch (Exception e) {
}
}
}
推荐答案
您的问题是avro包含了架构.
Your problem is that the avro has the schema included.
如果要读取Avro,则应使用其他DataReader,DataFileReader
If you want to read the avro you should to use other DataReader, DataFileReader
这里是一个示例,说明如何使用模式读取byte []格式的avro
Here is a example that how read an avro in byte[] format with schema
Scala示例:
def deserializeGenericWithSchema(message: Array[Byte]): Seq[GenericRecord] = {
val reader: DatumReader[GenericRecord] = new SpecificDatumReader[GenericRecord]()
val fileReader = new DataFileReader(new SeekableByteArrayInput(message),reader)
extractRec(fileReader,Seq.empty[GenericRecord])
}
@tailrec
def extractRec(fileReader: DataFileReader[GenericRecord], acc: Seq[GenericRecord]):Seq[GenericRecord] = {
if (fileReader.hasNext) {
val newElement = fileReader.next
extractRec(fileReader,acc :+ newElement)
} else {
acc
}
}
Java示例:
public List<GenericRecord> deserializeGenericWithSchema(byte[] message) throws IOException {
List<GenericRecord>listOfRecords = new ArrayList<>();
DatumReader<GenericRecord> reader = new SpecificDatumReader<>();
DataFileReader<GenericRecord> fileReader =
new DataFileReader<>(new SeekableByteArrayInput(message),reader);
while (fileReader.hasNext()) {
listOfRecords.add(fileReader.next());
}
return listOfRecords;
}
PD:我已经在Scala中编写了解决方案,然后未经测试就接触了Java.也许Java解决方案并不完全完美
PD: I have written the solution in scala and then I have traduced to Java, without testing. Maybe the Java solution is not completely perfect
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