GBK文件转UTF8文件

在编程的世界中，文件转换是经常见的，本文介绍了如何把GBK编码的文件转换成UTF8编码的文件。

主要利用类，为java.io.InputStreamReader和java.io.OutputStreamWriter

方法如下：

    public static void GBKFileToUtf8File(String filename) throws IOException {
        final String shift = "GBK";
        final String utf8 = "utf-8";

        String backupfilename = filename + ".backup";
        File f = new File(filename);
        File outf = new File(backupfilename);
        f.renameTo(outf);

        java.io.FileInputStream in = new java.io.FileInputStream(backupfilename);
        java.io.InputStreamReader isr = new java.io.InputStreamReader(in, shift);
        java.io.BufferedReader br = (new java.io.BufferedReader(isr));

        // open output stream
        java.io.FileOutputStream out = new java.io.FileOutputStream(filename);
        java.io.BufferedWriter bw = new java.io.BufferedWriter(
                new java.io.OutputStreamWriter(out, utf8));

        char[] buffer = new char[4096];
        int len;
        while ((len = br.read(buffer)) != -1)
            bw.write(buffer, 0, len);
        br.close();
        bw.flush();
        bw.close();
    }