package csdn;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class ReverseRead {
    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("test.txt")));
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("test1.txt")));
            String str = "";
            while ((str = br.readLine()) != null) {                
                bw.write(Reverse(str) + "\n");
                bw.flush();
            }
            br = new BufferedReader(new InputStreamReader(new FileInputStream("test1.txt")));
            String s = "";
            while ((s = br.readLine()) != null) {
                System.out.println(s);
            }
            br.close();
            bw.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }    
    }
    
    /**
     * 获得逆序的字符串
     * @param str 
     * @return str的逆序
     */
    private static String Reverse(String str) {
        char[] c = str.toCharArray();
        StringBuilder sb = new StringBuilder();
        for (int i = c.length - 1; i >= 0; i--) {
            sb.append(c[i] + "");
        }
        return sb.toString();
    }
}

------解决方案--------------------
1.读取文件1内容
2.将文件内容反转
3.将反转内容写入文件

假设文件一可以用字符流操作：

public static void reverse(String fileUrl) {
		BufferedReader br = null;
		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(fileUrl)));
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		
		BufferedWriter bw = null;
		try {
			bw = new BufferedWriter(new OutputStreamWriter(
					new FileOutputStream(fileUrl+"_Copy")));
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		
		String lineValue = "";
		try {
			while ((lineValue = br.readLine()) != null) {
				int length = lineValue.length();
				//char[] c = new char[length];
				for (int i = length-1; i >=0 ; i--) {
					//c[length -i -1] = lineValue.charAt(i);
					bw.write(lineValue.charAt(i));
				}
				bw.write("\n");
				//lineValue = new String(c);
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		try {
			br.close();
			bw.flush();
			bw.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}


功能差不多实现了。但可能有未知的BUG，没时间去看。楼主自己看看。