Java –如何将文件转换为字节[]

àì夳堔傛蜴生んèń 2023-02-15 07:38 10阅读 0赞

要将文件转换为byte \[\]，请尝试以下操作：

File file = new File("/temp/abc.txt");
      //init array with file length
      byte[] bytesArray = new byte[(int) file.length()]; 
    
      FileInputStream fis = new FileInputStream(file);
      fis.read(bytesArray); //read file into bytes[]
      fis.close();
    			
      return bytesArray;

或NIO

String filePath = "/temp/abc.txt";
    
      byte[] bFile = Files.readAllBytes(new File(filePath).toPath());
      //or this
      byte[] bFile = Files.readAllBytes(Paths.get(filePath));

## 完整的例子 ##

这个Java示例向您展示了如何使用经典的`FileInputStream`以及`java.nio`类将文件读入字节数组。

FileToArrayOfBytes.java

package com.mkyong;
    
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.nio.file.Files;
    import java.nio.file.Path;
    import java.nio.file.Paths;
    
    public class FileToArrayOfBytes {
    
        public static void main(String[] args) {
    
            try {
    
                // convert file to byte[]
                byte[] bFile = readBytesFromFile("C:\\temp\\testing1.txt");
    
                //java nio
                //byte[] bFile = Files.readAllBytes(new File("C:\\temp\\testing1.txt").toPath());
                //byte[] bFile = Files.readAllBytes(Paths.get("C:\\temp\\testing1.txt"));
    
                // save byte[] into a file
                Path path = Paths.get("C:\temp\\test2.txt");
                Files.write(path, bFile);
    
                System.out.println("Done");
    
                //Print bytes[]
                for (int i = 0; i < bFile.length; i++) {
                    System.out.print((char) bFile[i]);
                }
    
            } catch (IOException e) {
                e.printStackTrace();
            }
    
        }
    
        private static byte[] readBytesFromFile(String filePath) {
    
            FileInputStream fileInputStream = null;
            byte[] bytesArray = null;
    
            try {
    
                File file = new File(filePath);
                bytesArray = new byte[(int) file.length()];
    
                //read file into bytes[]
                fileInputStream = new FileInputStream(file);
                fileInputStream.read(bytesArray);
    
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (fileInputStream != null) {
                    try {
                        fileInputStream.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
    
            }
    
            return bytesArray;
    
        }
    
    }

## 参考文献 ##

1.  [Java –如何将byte \[\]保存到文件][Java _byte]
2.  [文件JavaDoc][JavaDoc]
3.  [FileInputStream JavaDoc][]

标签： [字节][Link 1] [文件][Link 2] [数组][Link 1] [java.io][] [java.nio][]

> 翻译自: [https://mkyong.com/java/how-to-convert-file-into-an-array-of-bytes/][https_mkyong.com_java_how-to-convert-file-into-an-array-of-bytes]

[Java _byte]: http://www.mkyong.com/java/how-to-convert-array-of-bytes-into-file/
[JavaDoc]: https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html
[FileInputStream JavaDoc]: https://docs.oracle.com/javase/8/docs/api/java/io/FileInputStream.html
[Link 1]: https://mkyong.com/tag/array-of-bytes/
[Link 2]: https://mkyong.com/tag/file/
[java.io]: https://mkyong.com/tag/java-io/
[java.nio]: https://mkyong.com/tag/java-nio/
[https_mkyong.com_java_how-to-convert-file-into-an-array-of-bytes]: https://mkyong.com/java/how-to-convert-file-into-an-array-of-bytes/