//写
    public static String writeTxt(String path,String txt)  {
        try{
            File f = new File(path);
            if (!f.exists()){
                f.createNewFile();
            }
            //定义编码   
            OutputStreamWriter write = new OutputStreamWriter(new FileOutputStream(f), "UTF-8");
            BufferedWriter writer = new BufferedWriter(write);
            writer.write(txt);
            writer.close();
        } catch (Exception e) {
            System.out.println("写文件内bai容操作出错");
            e.printStackTrace();
        }



        FileWriter writer;
        try {
            writer = new FileWriter(path);
            writer.write("");
            writer.write(txt);
            writer.flush();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
   //指定原文编码 
    public static void txtWriter(String path,String txt,){
		FileWriter fw = null;
		try {			
			//如果文件存在，则追加内容；如果文件不存在，则创建文件
			File f=new File(path);			
			if(!f.exists()){
				 //f.createNewFile();//如果文件不存在，则创建文件
				 fw = new FileWriter(path);
			        fw.flush();
			 }						
			fw.close();							
			FileOutputStream fos=new FileOutputStream(path,true);
			//写入时指定原来的编码格式
			OutputStreamWriter osw=new OutputStreamWriter(fos,getFilecharset(new File(path)));
			PrintWriter pw = new PrintWriter(osw);			
			pw.append(txt);				
									
			pw.flush(); // 清空缓冲区的数据流
			//pw.println("copy "+fileNames[i]+" c:\\u\\201506");
			pw.close();
			osw.close();
			fos.close();			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

    //读
    public static String read(File file){
        String encoding=getFilecharset(file);
        StringBuilder result = new StringBuilder();
        try{
            InputStreamReader read = new InputStreamReader (new FileInputStream(file),encoding);
            BufferedReader br = new BufferedReader(read);
            String s = null;
            
            while((s = br.readLine())!=null){//使用readLine方法，一次读一行
                result.append(s+"\r\n");//换行               
            }
            br.close();
        }catch(Exception e){
            e.printStackTrace();
        }
        System.out.println(result);
        return result.toString();
    }

    //编码识别
    public static String getFilecharset(File sourceFile) {
        String charset = "GBK";
        byte[] first3Bytes = new byte[3];
        try {
            boolean checked = false;
            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(sourceFile));
            bis.mark(0);
            int read = bis.read(first3Bytes, 0, 3);
            if (read == -1) {
                return charset;
            } else if (first3Bytes[0] == (byte) 0xFF
                    && first3Bytes[1] == (byte) 0xFE) {
                charset = "UTF-16LE";
                checked = true;
            } else if (first3Bytes[0] == (byte) 0xFE
                    && first3Bytes[1] == (byte) 0xFF) {
                charset = "UTF-16BE";
                checked = true;
            } else if (first3Bytes[0] == (byte) 0xEF
                    && first3Bytes[1] == (byte) 0xBB
                    && first3Bytes[2] == (byte) 0xBF) {
                charset = "UTF-8";
                checked = true;
            }
            bis.reset();
            if (!checked) {
                int loc = 0;
                while ((read = bis.read()) != -1) {
                    loc++;
                    if (read >= 0xF0){
                        break;}
                    if (0x80 <= read && read <= 0xBF)
                    {break;}
                    if (0xC0 <= read && read <= 0xDF) {
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF)
                        {continue;}
                        else
                        {break;}
                    } else if (0xE0 <= read && read <= 0xEF) {
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF) {
                            read = bis.read();
                            if (0x80 <= read && read <= 0xBF) {
                                charset = "UTF-8";
                                {break;}
                            } else
                            {break;}
                        } else
                        { break;}
                    }
                }
            }
            bis.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return charset;
    }
    
    //InputStream  流输出内容
    
     //<1>创建字节数组输出流，用来输出读取到的内容
           ByteArrayOutputStream baos = new ByteArrayOutputStream();
           //<2>创建缓存大小
           byte[] buffer = new byte[1024]; // 1KB
           //每次读取到内容的长度
           int len = -1;
           //<3>开始读取输入流中的内容
           while ((len = in.read(buffer)) != -1) { //当等于-1说明没有数据可以读取了
               baos.write(buffer, 0, len);   //把读取到的内容写到输出流中
           }
           //<4> 把字节数组转换为字符串
           String content = baos.toString();
           //<5>关闭输入流和输出流
           in.close();
           baos.close();
           //<6>返回字符串结果