使用通道和byteBuffer进行大文件分批传输

女爷i 2022-08-10 10:52 158阅读 0赞

import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.nio.ByteBuffer;
    import java.nio.channels.FileChannel;
    import java.nio.channels.FileChannel.MapMode;
    
    public class AdvancedCopy {
    
    	public void advancedCopy(File sourse,File target) throws IOException{
    		long fileSize = sourse.length();
    		int bufferLength = 1024*1024*2;//每次传输2m
    		int times = (int) (fileSize/bufferLength);//用于计算最后一次还剩多少，并限定for的次数
    		int remain = (int) (fileSize - times*bufferLength);
    		
    		FileInputStream fileInputStream = new FileInputStream(sourse);
    		FileChannel fileChannel = fileInputStream.getChannel();//从输入流获得通道
    		ByteBuffer byteBuffer = null;//字节缓冲区
    		
    		FileOutputStream fileOutputStream = new FileOutputStream(target);
    		FileChannel fileChannel2 = fileOutputStream.getChannel();//从输出流获得通道
    		int i = 0;//记录第几次传输
    				for (; i < times; i++) {//i是第几次传输
    					byteBuffer = fileChannel.map(MapMode.READ_ONLY, i*bufferLength, bufferLength);//读取指定长度的字节到内存中的bytebuffer中，第二个参数是起始字节，第三个参数是读写数量
    					fileChannel2.write(byteBuffer);
    					System.out.println("正在进行"+i+"/"+times);
    				}
    				byteBuffer = fileChannel.map(MapMode.READ_ONLY, i*bufferLength, remain);//最后一次读写
    				System.out.println("传输完成");
    		
    		
    	}
    
    }

调用方法

File sourse = new File("E:/Edius6dot02-cr.zip");
    File target = new File("i:/Edius6dot02-cr.zip");
    new AdvancedCopy().advancedCopy(sourse, target);