java 读取parquet中fixed类型的数据

parquet格式的文件中，有一种类型如下所示：

{
    "name" : "speed",
    "type" : [ "null", {
      "type" : "fixed",
      "name" : "decimal_11_3",
      "size" : 5,
      "logicalType" : "decimal",
      "precision" : 11,
      "scale" : 3
    } ],
    "default" : null,
    "field-id" : 1
  }

通过getString读取对应的字段，读出来是乱码，需要按照decimal格式读取出来数值。读取方法如下：

ParquetReader.Builder<Group> builder = ParquetReader.builder(new GroupReadSupport(),path);
ParquetReader<Group> reader = builder.build();
SimpleGroup group =null;
GroupType groupType = null;
while((group = (SimpleGroup)reader.read())!=null){
    if(groupType == null){
        groupType = group.getType();
    }
    StringJoiner sj = new StringJoiner(",");
    for(int i=0;i<groupType.getFieldCount();i++){
        String tmpName = groupType.getFieldName(i);
        Type type = groupType.getType(i);
        String typename = type.asPrimitiveType().getPrimitiveTypeName().name();
        if (typename.equals("FIXED_LEN_BYTE_ARRAY")){
            byte[] fixedFieldData = group.getBinary(i, 0).getBytes();
            BigInteger bint= new BigInteger(fixedFieldData);
            BigDecimal decimalValue = new BigDecimal(bint, 3);
            float v = decimalValue.floatValue();
        }else {
            String tmp ="";
            //捕获 data 为 null异常
            try {
                tmp = group.getValueToString(i,0);
            }catch (Exception e){}
        }
    }
}

其他类型的：int32、int64、binary等，直接用getValueToString方法读取即可。