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本文介紹了要緩沖或字節(jié)流的拼圖編寫器的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學(xué)習(xí)吧！

問題描述

我有一個Java應(yīng)用程序，可以將JSON消息轉(zhuǎn)換為PARQUET格式。Java中有沒有可以寫入緩沖區(qū)或字節(jié)流的拼圖寫入器？在大多數(shù)示例中，我都看到過寫入文件。

推薦答案

TLDR；您需要實現(xiàn)OutputFile，例如類似于：

的內(nèi)容

import org.apache.parquet.io.OutputFile;
import org.apache.parquet.io.PositionOutputStream;

import java.io.BufferedOutputStream;
import java.io.IOException;

public class ParquetBufferedWriter implements OutputFile {

    private final BufferedOutputStream out;

    public ParquetBufferedWriter(BufferedOutputStream out) {
        this.out = out;
    }

    @Override
    public PositionOutputStream create(long blockSizeHint) throws IOException {
        return createPositionOutputstream();
    }

    private PositionOutputStream createPositionOutputstream() {
        return new PositionOutputStream() {
            @Override
            public long getPos() throws IOException {
                return 0;
            }

            @Override
            public void write(int b) throws IOException {
                out.write(b);
            }
        };
    }

    @Override
    public PositionOutputStream createOrOverwrite(long blockSizeHint) throws IOException {
        return createPositionOutputstream();
    }

    @Override
    public boolean supportsBlockSize() {
        return false;
    }

    @Override
    public long defaultBlockSize() {
        return 0;
    }

}

您的作者應(yīng)該是這樣的：

    ParquetBufferedWriter out = new ParquetBufferedWriter();
        try (ParquetWriter<Record> writer = AvroParquetWriter.
                <Record>builder(out)
                .withRowGroupSize(DEFAULT_BLOCK_SIZE)
                .withPageSize(DEFAULT_PAGE_SIZE)
                .withSchema(SCHEMA)
                .build()) {

            for (Record record : records) {
                writer.write(record);
            }
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }

這篇關(guān)于要緩沖或字節(jié)流的拼圖編寫器的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，