示例程式碼如下

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Date;

public class FileDemo4 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		File f = new File("C:/123/data","first.txt");//檔案1裡有內容
		File s = new File("C:/123/data","second.txt");//檔案2為空
		try {
			FileReader fr=new FileReader(f);//讀檔案1
			FileWriter sw=new FileWriter(s);//寫檔案2
			BufferedReader bufr=new BufferedReader(fr);//檔案1快取機制
			String str="";
			while((str=bufr.readLine())!=null){//當讀取的字串不為空時
				sw.write(str);//在檔案2中寫入檔案1內容
                                sw.write("\n");
			}
			fr.close();
			sw.close();
			bufr.close();

			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
			
		
		
		
		
		
	}

}