编写一个程序， 将 a.txt 文件中的单词与 b.txt 文件中的 单词交替合并到 c.txt 文件中， a.txt 文件中的单词用回车符 分隔， b.txt 文件中用回车或空格进行分隔。

package cn.itcast;  

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;  

public class MainClass{
    public static void main(String[] args) throws Exception{
        FileManager a = new FileManager("a.txt",new char[]{'\n'});
        FileManager b = new FileManager("b.txt",new char[]{'\n',' '});
        FileWriter c = new FileWriter("c.txt");
        String aWord = null;
        String bWord = null;
        while((aWord = a.nextWord()) !=null ){
            c.write(aWord + "\n");
            bWord = b.nextWord();
            if(bWord != null)
                c.write(bWord + "\n");
        }  

        while((bWord = b.nextWord()) != null){
            c.write(bWord + "\n");
        }
        c.close();
    }  

}  

class FileManager{  

    String[] words = null;
    int pos = 0;
    public FileManager(String filename,char[] seperators) throws Exception{
        File f = new File(filename);
        FileReader reader = new FileReader(f);
        char[] buf = new char[(int)f.length()];
        int len = reader.read(buf);
        String results = new String(buf,0,len);
        String regex = null;
        if(seperators.length >1 ){
            regex = "" + seperators[0] + "|" + seperators[1];
        }else{
            regex = "" + seperators[0];
        }
        words = results.split(regex);
    }  

    public String nextWord(){
        if(pos == words.length)
            return null;
        return words[pos++];
    }  

}