问使用eclipse学习字符读写中遇到java.io.FileNotFoundException？

按照书中编写的，不论是改成"res/FileRWDemo.java"还是"FileRWDemo.java"

都显示找不到文件，"res/FileRWDemo.java"文件应该放在那里才能被找到

package ioStreamRW;

import java.io.*;

public class FileRWDemo {

public static void main(String[] args) {

try {

FileReader fileReader = new FileReader("res/FileRWDemo.java"); //此处出错

FileWriter fileWriter = new FileWriter("res/FileRWDemo.java");

int in =0;

char[] wlnChar = {'\r','\n'};

while((in = fileReader.read()) != -1) {

if(in == '\n')

fileWriter.write(wlnChar);

else

fileWriter.write(in);

}

fileReader.close();

fileWriter.close();

}

catch(Exception e) {

e.printStackTrace();

}

}

}