这是一个程序，我们正在读取和打印数组的字节偏移量和长度使用String Builder和写入数组的字节偏移量长度到新文件。

在这里输入代码

import java.io.File;   
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;        

//*This is a program where we are reading and printing array of bytes offset and length using StringBuilder and Writing the array of bytes offset length to the new file*//     

public class ReadandWriteAByte {
    public void readandWriteBytesToFile(){
        File file = new File("count.char"); //(abcdefghijk)
        File bfile = new File("bytefile.txt");//(New File)
        byte[] b;
        FileInputStream fis = null;              
        FileOutputStream fos = null;          

        try{               
            fis = new FileInputStream (file);           
            fos = new FileOutputStream (bfile);             
            b = new byte [1024];              
            int i;              
            StringBuilder sb = new StringBuilder();

            while ((i = fis.read(b))!=-1){                  
                sb.append(new String(b,5,5));               
                fos.write(b, 2, 5);               
            }               

            System.out.println(sb.toString());               
        }catch (IOException e) {                    
            e.printStackTrace();                
        }finally {               
            try {              
                if(fis != null);           
                    fis.close();    //This helps to close the stream          
            }catch (IOException e){           
                e.printStackTrace();              
            }            
        }               
    }               

    public static void main (String args[]){              
        ReadandWriteAByte rb = new ReadandWriteAByte();              
        rb.readandWriteBytesToFile();              
    }                 
}                

O/P在控制台:fghij

O/P在新文件:cdefg

这是一个程序，我们正在读取和打印数组的字节偏移量和长度使用String Builder和写入数组的字节偏移量长度到新文件。

在这里输入代码

import java.io.File;   
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;        

//*This is a program where we are reading and printing array of bytes offset and length using StringBuilder and Writing the array of bytes offset length to the new file*//     

public class ReadandWriteAByte {
    public void readandWriteBytesToFile(){
        File file = new File("count.char"); //(abcdefghijk)
        File bfile = new File("bytefile.txt");//(New File)
        byte[] b;
        FileInputStream fis = null;              
        FileOutputStream fos = null;          

        try{               
            fis = new FileInputStream (file);           
            fos = new FileOutputStream (bfile);             
            b = new byte [1024];              
            int i;              
            StringBuilder sb = new StringBuilder();

            while ((i = fis.read(b))!=-1){                  
                sb.append(new String(b,5,5));               
                fos.write(b, 2, 5);               
            }               

            System.out.println(sb.toString());               
        }catch (IOException e) {                    
            e.printStackTrace();                
        }finally {               
            try {              
                if(fis != null);           
                    fis.close();    //This helps to close the stream          
            }catch (IOException e){           
                e.printStackTrace();              
            }            
        }               
    }               

    public static void main (String args[]){              
        ReadandWriteAByte rb = new ReadandWriteAByte();              
        rb.readandWriteBytesToFile();              
    }                 
}                

O/P在控制台:fghij

O/P在新文件:cdefg

从Java 7开始，您可以使用try-with-resources语句来避免资源泄漏，并使您的代码更易于阅读。这里有更多。

要把你的byteArray写入一个文件，你会做:

try (FileOutputStream fos = new FileOutputStream("fullPathToFile")) {
    fos.write(byteArray);
} catch (IOException ioe) {
    ioe.printStackTrace();
}

我知道它是用InputStream完成的

实际上，你会写入一个文件输出…

使用java.nio.file的另一个解决方案:

byte[] bytes = ...;
Path path = Paths.get("C:\\myfile.pdf");
Files.write(path, bytes);

基本的例子:

String fileName = "file.test";

BufferedOutputStream bs = null;

try {

    FileOutputStream fs = new FileOutputStream(new File(fileName));
    bs = new BufferedOutputStream(fs);
    bs.write(byte_array);
    bs.close();
    bs = null;

} catch (Exception e) {
    e.printStackTrace()
}

if (bs != null) try { bs.close(); } catch (Exception e) {}