求段简单JAVA的代码

import java.io.*;

public class Test{

public static void main(String s[]){

byte[] b1=new byte[3];

byte[] b2=new byte[3];

try{

File f=new File("F:\\11.txt");

RandomAccessFile raf=new RandomAccessFile(f,"rw");

long len=raf.length();

raf.read(b1,0,3);

String str=bytesToHexString(b1);

System.out.println("前三个字节哈希码是："+b1.toString());

System.out.println("转换为十六进制后是："+str);

raf.seek(len-3);

//raf.read(b2,(int)(len-3),3);

b2[0]=raf.readByte();

b2[1]=raf.readByte();

b2[2]=raf.readByte();

str=bytesToHexString(b2);

System.out.println("后三个自己哈希码是："+b2.toString());

System.out.println("转换为十六进制后是："+str);

}catch(Exception e){System.out.println("error");}

}

public static final String bytesToHexString(byte[] bArray) {

StringBuffer sb = new StringBuffer(bArray.length);

String sTemp;

for (int i = 0; i < bArray.length; i++) {

sTemp = Integer.toHexString(0xFF & bArray[i]);

if (sTemp.length() < 2)

sb.append(0);

sb.append(sTemp.toUpperCase());

}

return sb.toString();

}

}

主要的除了转16进制，就是用RandomAccessFile的seek来快速定位倒数的三个字节的位置。还有问题的话，baiduhi我，随时在线