彻底解决android读取中文txt的乱码（自动判断文档类型并转码）

public String convertCodeAndGetText(String str_filepath) {// 转码

File file = new File(str_filepath);
BufferedReader reader;
String text = "";
try {
// FileReader f_reader = new FileReader(file);
// BufferedReader reader = new BufferedReader(f_reader);
FileInputStream fis = new FileInputStream(file);
BufferedInputStream in = new BufferedInputStream(fis);
in.mark(4);
byte[] first3bytes = new byte[3];
in.read(first3bytes);//找到文档的前三个字节并自动判断文档类型。
in.reset();
if (first3bytes[0] == (byte) 0xEF && first3bytes[1] == (byte) 0xBB
&& first3bytes[2] == (byte) 0xBF) {// utf-8

reader = new BufferedReader(new InputStreamReader(in, "utf-8"));

} else if (first3bytes[0] == (byte) 0xFF
&& first3bytes[1] == (byte) 0xFE) {

reader = new BufferedReader(
new InputStreamReader(in, "unicode"));
} else if (first3bytes[0] == (byte) 0xFE
&& first3bytes[1] == (byte) 0xFF) {

reader = new BufferedReader(new InputStreamReader(in,
"utf-16be"));
} else if (first3bytes[0] == (byte) 0xFF
&& first3bytes[1] == (byte) 0xFF) {

reader = new BufferedReader(new InputStreamReader(in,
"utf-16le"));
} else {

reader = new BufferedReader(new InputStreamReader(in, "GBK"));
}
String str = reader.readLine();

while (str != null) {
text = text + str + "/n";
str = reader.readLine();

}
reader.close();

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return text;
}