android学习:自动识别文本文件编码格式

/**
* 判断文件的编码格式
* @param fileName :file
* @return 文件编码格式
* @throws Exception
*/
public static String codeString(String fileName) throws Exception{
BufferedInputStream bin = new BufferedInputStream(
new FileInputStream(fileName));
int p = (bin.read() << 8) + bin.read();
String code = null;

switch (p) {
case 0xefbb:
code = "UTF-8";
break;
case 0xfffe:
code = "Unicode";
break;
case 0xfeff:
code = "UTF-16BE";
break;
default:
code = "GBK";
}

return code;
}