1、dd命令

of：fileName为文件名称，例如test.txt ；

bs：设置一次复制的大小，例如1M；

count：设置复制次数，例如100；

dd if=/dev/zero of=<fileName> bs=<一次复制的大小> count=<复制的次数>

例如：

dd if=/dev/zero of=1.txt bs=1M count=100

2、Java快速生成

两种方式都可以生成

package com.jxnu.test;import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;/*** @program: CreateFile* @author: xiaojing* @create: 2020-03-01-09-46*/
public class Test {public static void main(String[] args) throws IOException {File file = new File("test.txt");long length = 1024*1024*15;//createFixLengthFile(file, length);createFile(file, length);}/*** 第一种方法* @param file* @param length* @throws IOException*/public static void createFixLengthFile(File file, long length) throws IOException{FileOutputStream fos = null;FileChannel output = null;try {fos = new FileOutputStream(file);output = fos.getChannel();output.write(ByteBuffer.allocate(1), length - 1);} finally {try {if (output != null) {output.close();}if (fos != null) {fos.close();}} catch (IOException e) {e.printStackTrace();}}}/*** * 第二种方法* @param file* @param length* @throws IOException*/private static void createFile(File file, long length) throws IOException {RandomAccessFile r = null;try {r = new RandomAccessFile(file, "rw");r.setLength(length);} finally {if (r != null) {r.close();}}}
}