package test;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import
 
 java.io.PrintWriter;

public class AnsiToUtf8 {
    /**
     * 讀寫檔案方式改變檔案編碼格式
     * @param path
     * @throws IOException
     */
    public static void ansiToUTF8(String path) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(path), "GB2312"
 
));
        String all = "";
        String line = null;
        while((line = br.readLine()) != null){
            all += line + "\r\n";
        }
        br.close();

        PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(path), "UTF-8")));
        out.write(all);
        out.flush();
        out.close();
    }
    /**
     * 判斷檔案編碼格式是否為UTF8
     * @param
 
 path
     * @return
     * @throws IOException
     */
    public static boolean isUTF8(String path) throws IOException{
        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(path));
        byte[] b = new byte[3];

        bis.mark(0);
        bis.read(b, 0, 3);

        if(b[0] == (byte)0xEF && b[1] == (byte)0xBB && b[2] == (byte)0xBF){
            bis.close();
            return true;
        }

        bis.reset();
        int read;
        while((read = bis.read()) != -1){
            if (read >= 0xF0)
                break;
            if (0x80 <= read && read <= 0xBF) // 單獨出現BF以下的，也算是GBK
                break;
            if (0xC0 <= read && read <= 0xDF) {
                read = bis.read();
                if (0x80 <= read && read <= 0xBF) // 雙位元組 (0xC0 - 0xDF)
                    continue;
                else
                    break;
            } else if (0xE0 <= read && read <= 0xEF) {// 也有可能出錯，但是機率較小
                read = bis.read();
                if (0x80 <= read && read <= 0xBF) {
                    read = bis.read();
                    if (0x80 <= read && read <= 0xBF) {
                        bis.close();
                        return true;
                    } else
                        break;
                } else
                    break;
            }
        }
        bis.close();
        return false;
    }
    /**
     * 遍歷資料夾下所有檔案
     * @param dir
     * @throws IOException
     */
    public static void traverseFolder(File dir) throws IOException{
        File[] files = dir.listFiles();
        for (File file : files) {
//          System.out.println(file.getName());
            if(file.isDirectory()){
                traverseFolder(file);
            }
            else if(file.getName().endsWith(".java") && !isUTF8(file.getAbsolutePath())){
                ansiToUTF8(file.getAbsolutePath());
            }
        }
    }

    public static void main(String[] args){
        File dir = new File("d:\\test");
        try {
            traverseFolder(dir);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}