成语接龙（英语单词链）

package 六月六号;

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

public class Test1 {

	public static void main(String[] args) throws IOException 
	{
		// TODO 自动生成的方法存根
		String filename ="D://dada.txt";
		File  a=new  File(filename);
		File  file=new  File("D://output.txt");
		long startTime = System.currentTimeMillis();
	 //judeFileExists(a);
	 if(judeFileExists(a))
		{
			danci(filename);
		}
	 else
	    { 
		  try {
	        	
        	  FileWriter fw =new FileWriter(file);
        	  fw.write("无此文件");
        	  fw.flush();
        	  fw.close();
        }
        catch (IOException e) {
	           e.printStackTrace();      
	       }
	    }
	 long endTime = System.currentTimeMillis();    //获取结束时间
	 System.out.println("程序运行时间：" + (endTime - startTime) + "ms");    //输出程序运行时间
	}

	public static void danci(String s) throws IOException {
		   
			BufferedReader br = new BufferedReader(new FileReader(s));
			StringBuffer sb = new StringBuffer();
			String text = null;
			while ((text = br.readLine()) != null) {
				sb.append(text);// 将读取出的字符追加到stringbuffer中
			}
			br.close(); // 关闭读入流
			String str = sb.toString().toLowerCase(); // 将stringBuffer转为字符并转换为小写
			String[] words = str.split("[^(a-zA-Z)]+"); // 非单词的字符来分割，得到所有单词
			StringBuffer yao = new StringBuffer();
			String b1=words[0];
			yao.append(b1);
			yao.append(" ");
			//System.out.println(b1);
			if(b1.equals(""))
			{
				System.out.println("文件为空");
				yao.append("文件为空");
			}
			else
			{
				if(words.length==1)
				{
					System.out.println("只有一个单词");
				}
			   
			String end=b1.substring(b1.length()-1,b1.length());
		   // System.out.println(end);
		   for(int i=1;i<words.length;i++)
		   {  
			 
		    String start=words[i].substring(0,1);
		    if(end.equals(start))
		     {
		    	if(judechong(yao,words[i]))
		    	{}
		    	else
		    	{
		    	end=words[i].substring(words[i].length()-1,words[i].length());
		    	yao.append(words[i]);
		    	yao.append(" ");
		    	}
		    	
		     }
		    } 
		    
		   if(yao.toString().equals(words[0]+" "))
		    {
				yao.append("无互联语句");
				System.out.println("无互联词");
		    }
		}
			
			
		  // for( String a:words)
		  // {
			 //  System.out.println(a);
		//   }
		 //  System.out.println(yao.toString()); 
		   File file =new File("D://output.txt");
	        try {
	             file.createNewFile();
	        } catch (IOException e) {
	           e.printStackTrace();      
	       }
	      
	        try {
	        	
	        	  FileWriter fw =new FileWriter(file);
	        	  fw.write(yao.toString());
	        	  fw.flush();
	        	  fw.close();
	        }
	        catch (IOException e) {
		           e.printStackTrace();      
		       }
			
	     
	}

public  static boolean  judechong(StringBuffer yao,String word)
{
	String a=yao.toString();
	boolean flag=false;
	String[] words = a.split("[^(a-zA-Z)]+"); // 非单词的字符来分割，得到所有单词
	for(int i=0;i<words.length;i++)
	{
		if(word.equals(words[i]))
		{
			flag=true;
		}
	}
	return flag;
}
// 判断文件是否存在
public static boolean judeFileExists(File file) {

    if (file.exists()) {
        System.out.println("文件存在");
        return true;
    } else {
        System.out.println("文件不存在");
        // try {
        //     file.createNewFile();
       //  } catch (IOException e) {
       // TODO Auto-generated catch block
      //      e.printStackTrace();      
     //   }
        return false;
    }
}
}