FileInputStream inFile=new FileInputStream("xxx.xxx");//文件名.文件類型

FileOutputStream outFile=new FileOutputStream("xxx.xxx"); //文件名.文件類型，如 a.bat

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
public class CopyA {
    public static void main(String[] args) {
        String curPath=System.getProperty ( "user.dir" );//得到用戶當前工作目錄
        System.out.println (curPath);
        try {
            //文件輸入流
            FileInputStream inFile=new FileInputStream ( curPath+"/a.txt" );
            //文件輸出流
            FileOutputStream outFile =new FileOutputStream ( curPath+"/b.txt" );
            //返回可以不受阻塞地從此文件輸入流中讀取的字節(jié)數(shù)
            while(inFile.available ()>0){
                int ch=inFile.read (); //從輸入流中讀取字符，并返回
                outFile.write (ch);    //將字符ch寫到輸出流中
            }
            inFile.close (); //關閉輸入流
            outFile.close ();//關閉輸出流
        }catch (FileNotFoundException e){
            System.out.println ("文件無法打開");
        }catch (IOException e){
            System.out.println ("文件無法讀寫");
        }
    }
}