Apache Parquet Column Framework Overview in the Java Class Library

Apache Parquet is an efficient columnist storage file format, which has the characteristics of compression, high performance and easy expansion.The Column framework is an important component in Apache Parqueet. It is used to read and write the ParQuet file in the Java class library. The Column framework allows developers to operate the Parquet file as a unit.It provides a method for reading and writing data to process column storage data in the Parquet file.When reading the Parquet file, the framework allows to read one or more columns at a time in an efficient way.Similarly, when writing a Parquet file, the framework allows writing as a unit to write, providing high -performance and high scalability. It is very simple to read the Parquet file using the Column framework.First, you need to create a ParQuet file reader, and then use the reader to open the ParQuet file.Next, you can use a column reader to read the data in the Parquet file.The following is a simple Java code example. Demonstrate how to use the column framework to read the column in the Parquet file: Path parquetFilePath = Paths.get("path/to/parquet/file.parquet"); ParquetFileReader reader = ParquetFileReader.open(ParquetIO.file(parquetFilePath)); ColumnReader<Integer> columnReader = reader.getColumnReader(new IntColumn<>("columnName")); int value; while (columnReader.hasValue()) { value = columnReader.getInteger(); System.out.println("Value: " + value); columnReader.consume(); } reader.close(); In the above example, first use the ParQuet file to open a ParQuet file with the method of `ParqueTFileRerereader.open ().Then, a series of readers were created by using the `GetColumnreader ()" method.In the While loop, use the `HasValue ()" method to check whether there are more values for reading, and then use the `Getinteger ()` method to read the integer value, and use the `consume () method to advance to the next value methodEssenceFinally, the file reader was turned off using the `Reader.close () method. For writing Parquet files, the Column framework also provides a simple and easy -to -use method.You need to create a ParQuet file writinger, and then use the editing writer to write into the ParQuet file.The following is a simple example. Demonstration of how to use the Column framework to write the column of the ParQuet file: Path parquetFilePath = Paths.get("path/to/parquet/file.parquet"); ParquetFileWriter writer = ParquetFileWriter.open(ParquetIO.file(parquetFilePath))); ColumnWriter<Integer> columnWriter = writer.createColumn(new IntColumn<>("columnName")); columnWriter.writeInteger(10); columnWriter.writeInteger(20); columnWriter.writeInteger(30); columnWriter.close(); writer.close(); In the above example, first use the Parquetfilewriter.open () method to create a ParQuet file writinger.Then, an integer column writer was created using the `CreateColumn ()` method.Next, use the `` WriteINTEGER () `method to write the integer value to the column writer.Finally, use the `Close ()` method to close the columns and file writing. In summary, the Column framework of Apache Parquet is an efficient and easy -to -use tool that is used to read and write a column to the Parquet file.It allows to operate the ParQuet file in a unit and provide a simple API to read and write the data.Whether reading large data sets or writing data to Parquet files, the Column framework provides high -performance and easy scalability.