救命呀，求助编写一个JAVA程序！

package test;

import java.io.*;

public class Test {
public static void main(String[] args) throws Exception {

RandomAccessFile ra = new RandomAccessFile(
"d:\\test.txt", "rw");
for (int i = 0; i < 20; i++) {
ra.writeInt(i);
}

RandomAccessFile raf = new RandomAccessFile(
"d:\\test.txt", "r");
raf.skipBytes(48);//每个整型占4个字节，也就是前12个数字不要，就是去掉48个字节，从第49个开始读
for(int j=0;j<8;j++){
System.out.println(raf.readInt());
}
}

}

import java.io.IOException;
import java.io.RandomAccessFile;

public class A {

public static void main(String[] args) throws IOException {
final String fileName = "test.txt";

RandomAccessFile randAccsFile = new RandomAccessFile(fileName, "rw");

for(int i = 0; i <= 19; i++){
randAccsFile.writeBytes(String.valueOf(i));
}

randAccsFile.seek(12);
byte[] ary = new byte[(int) (randAccsFile.length() - 12)];
randAccsFile.readFully(ary);

randAccsFile.close();
System.out.println(new String(ary));
}

}

---------------testing
111213141516171819

第一个人就可以，