Java – byte[]をファイルに保存する方法

getdocs

4年前

byte[]をファイルに保存するには、次のようにしてください:

  FileOutputStream fos = new FileOutputStream(fileDest);
  fos.write(bytesArray);
  fos.close();

またはNIO

  Path path = Paths.get(fileDest);
  Files.write(path, bytesArray);

完全な例

このJavaの例では、ファイルをバイト配列に読み込んで、古典的なtry-catch-try-catch、JDK 7のtry-resourcesおよびJava.NIOソリューションを使用してバイト配列を新しいファイルに保存する方法を示します。

ArrayOfBytesToFile.java

package com.mkyong;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class ArrayOfBytesToFile {

    private static final String UPLOAD__FOLDER = "C:\\temp\\";

    public static void main(String[]args) {

        FileInputStream fileInputStream = null;

        try {

            File file = new File("C:\\temp\\testing1.txt");
            byte[]bFile = new byte[(int) file.length()];

           //read file into bytes[]            fileInputStream = new FileInputStream(file);
            fileInputStream.read(bFile);

           //save bytes[]into a file
            writeBytesToFile(bFile, UPLOAD__FOLDER + "test1.txt");
            writeBytesToFileClassic(bFile, UPLOAD__FOLDER + "test2.txt");
            writeBytesToFileNio(bFile, UPLOAD__FOLDER + "test3.txt");

            System.out.println("Done");

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fileInputStream != null) {
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }
    }

   //Classic, < JDK7
    private static void writeBytesToFileClassic(byte[]bFile, String fileDest) {

        FileOutputStream fileOuputStream = null;

        try {
            fileOuputStream = new FileOutputStream(fileDest);
            fileOuputStream.write(bFile);

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fileOuputStream != null) {
                try {
                    fileOuputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }

   //Since JDK 7 - try resources
    private static void writeBytesToFile(byte[]bFile, String fileDest) {

        try (FileOutputStream fileOuputStream = new FileOutputStream(fileDest)) {
            fileOuputStream.write(bFile);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

   //Since JDK 7, NIO
    private static void writeBytesToFileNio(byte[]bFile, String fileDest) {

        try {
            Path path = Paths.get(fileDest);
            Files.write(path, bFile);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

}