Java语言文件与Byte数组相互转换（方法二）

最近项目中需要把文件转为Byte数组进行操作，特此记录便于日后查阅。

package com.openailab.oascloud.file.util;

import com.openailab.oascloud.file.common.consts.BootstrapConst;

import java.io.*;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;

/**
 * @description: 文件与Byte数组相互转换
 * @author: zhangzhixiang
 * @createDate: 2020/1/7
 * @version: 1.0
 */
public class Byte2InputStream {
    /**
     * 将文件转为byte数组
     *
     * @param filename
     * @return byte[]
     * @author zxzhang
     * @date 2019/10/8
     */
    public static byte[] file2ByteArray(String filename) throws IOException {
        FileChannel fc = null;
        try {
            fc = new RandomAccessFile(filename, "r").getChannel();
            MappedByteBuffer byteBuffer = fc.map(FileChannel.MapMode.READ_ONLY, 0,
                    fc.size()).load();
            byte[] result = new byte[(int) fc.size()];
            if (byteBuffer.remaining() > 0) {
                byteBuffer.get(result, 0, byteBuffer.remaining());
            }
            return result;
        } catch (IOException e) {
            e.printStackTrace();
            throw e;
        } finally {
            try {
                fc.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 将Byte数组转换成文件
     *
     * @param bytes
     * @param filePath
     * @param fileName
     * @return void
     * @author zxzhang
     * @date 2019/10/8
     */
    public static void byteArray2File(byte[] bytes, String filePath, String fileName) {
        BufferedOutputStream bos = null;
        FileOutputStream fos = null;
        File file = null;
        try {
            File dir = new File(filePath);
            if (!dir.exists()) {// 判断文件目录是否存在
                dir.mkdirs();
            }
            file = new File(filePath + BootstrapConst.PATH_SEPARATOR + fileName);
            fos = new FileOutputStream(file);
            bos = new BufferedOutputStream(fos);
            bos.write(bytes);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

到此 Java语言文件和Byte数组相互转换介绍完成。