exer8_4.java

开始学JAVA老师布置的作业一学期的哦希望新手有用

import java.io.*;
import java.util.*;
import java.lang.*;
class Exer8_4
{
	public static void write(String filename,String text) throws IOException
	{
		PrintWriter out = new  PrintWriter(new BufferedWriter(new FileWriter(filename)));
		out.println(text);
		out.close();
	}
	public static String read(String filename) throws IOException
	{
		StringBuffer sb=new StringBuffer();
		BufferedReader in = new BufferedReader(new FileReader(filename));
		String s;
		while((s=in.readLine())!= null)
		{
			sb.append(s);
			sb.append("\n");

		}
		in.close();
		sb.delete(sb.length()-1,sb.length());
		return sb.toString();
	}
	public static void main(String[] args) throws Exception
	{
		String file=read("STUDENT.DAT");
		write("STUDENT_bak.DAT",file);
		System.out.print("复制文件 STUDENT.DAT 完成!\n\n");
	}
}