使用java语言将execl文件转换为parquet文件简单示例

您好，我可以回答这个问题。您可以使用Apache POI和Apache Parquet库来实现这个转换。首先，您需要使用POI库读取Excel文件中的数据，然后将数据转换为Parquet格式并写入Parquet文件。具体实现可以参考以下代码示例：

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.apache.parquet.hadoop.ParquetWriter;
import org.apache.parquet.hadoop.metadata.CompressionCodecName;
import org.apache.parquet.schema.MessageType;
import org.apache.parquet.schema.MessageTypeParser;
import org.apache.parquet.schema.Types;
import org.apache.parquet.schema.Types.MessageTypeBuilder;
import org.apache.parquet.schema.Types.PrimitiveTypeBuilder;

public class ExcelToParquetConverter {

    public static void main(String[] args) throws IOException {
        // 读取Excel文件
        Sheet sheet = WorkbookFactory.create(new File("input.xlsx")).getSheetAt();

        // 构建Parquet文件的Schema
        MessageType schema = buildSchema(sheet);

        // 创建Parquet文件的Writer
        ParquetWriter<Row> writer = createWriter(schema, "output.parquet");

        // 将Excel文件中的数据转换为Parquet格式并写入Parquet文件
        for (Row row : sheet) {
            List<Object> values = new ArrayList<>();
            for (Cell cell : row) {
                values.add(getCellValue(cell));
            }
            writer.write(new org.apache.parquet.hadoop.example.GroupWriteSupport().toGroup(schema, values));
        }

        // 关闭Parquet文件的Writer
        writer.close();
    }

    private static MessageType buildSchema(Sheet sheet) {
        MessageTypeBuilder builder = Types.buildMessage();
        builder.setName(sheet.getSheetName());
        for (int i = ; i < sheet.getRow().getLastCellNum(); i++) {
            String columnName = sheet.getRow().getCell(i).getStringCellValue();
            PrimitiveTypeBuilder columnBuilder = builder.primitive(columnName, Types.PrimitiveType.PrimitiveTypeName.BINARY);
            columnBuilder.optional(1);
        }
        return builder.named(sheet.getSheetName());
    }

    private static ParquetWriter<Row> createWriter(MessageType schema, String outputPath) throws IOException {
        return org.apache.parquet.hadoop.ParquetWriter.builder(new org.apache.parquet.hadoop.Path(outputPath))
                .withWriteMode(org.apache.parquet.hadoop.ParquetFileWriter.Mode.OVERWRITE)
                .withCompressionCodec(CompressionCodecName.SNAPPY)
                .withRowGroupSize(ParquetWriter.DEFAULT_BLOCK_SIZE)
                .withPageSize(ParquetWriter.DEFAULT_PAGE_SIZE)
                .withSchema(schema)
                .build();
    }

    private static Object getCellValue(Cell cell) {
        switch (cell.getCellType()) {
        case STRING:
            return cell.getStringCellValue();
        case NUMERIC:
            return cell.getNumericCellValue();
        case BOOLEAN:
            return cell.getBooleanCellValue();
        case FORMULA:
            return cell.getCellFormula();
        default:
            return null;
        }
    }

}

希望这个示例对您有所帮助。