java写入文件编码格式为ansi_java 获取文本文件编码格式

最近java读取文件的时候，经常碰到中文乱码，特研究了一下java 的编码格式，在java 中

java编码与txt编码对应 java txt

unicode unicode big endian

utf-8 utf-8

utf-16 unicode

gb2312 ANSIjava 读取txt如果编码格式不对就会出现乱码格式，通过下边方法获取文本文件编码格式，然后以指定的编码读取文件，就不会出现乱码(简单测试了一下，但是也不保证100%)

private 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; //文件编码为 ANSI

} else if (first3Bytes[0] == (byte) 0xFF

&& first3Bytes[1] == (byte) 0xFE) {

charset = "UTF-16LE"; //文件编码为 Unicode

checked = true;

} else if (first3Bytes[0] == (byte) 0xFE

&& first3Bytes[1] == (byte) 0xFF) {

charset = "UTF-16BE"; //文件编码为 Unicode big endian

checked = true;

} else if (first3Bytes[0] == (byte) 0xEF

&& first3Bytes[1] == (byte) 0xBB

&& first3Bytes[2] == (byte) 0xBF) {

charset = "UTF-8"; //文件编码为 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) // 单独出现BF以下的，也算是GBK

break;

if (0xC0 <= read && read <= 0xDF) {

read = bis.read();

if (0x80 <= read && read <= 0xBF) // 双字节 (0xC0 - 0xDF)

// (0x80

// - 0xBF),也可能在GB编码内

continue;

else

break;

} else if (0xE0 <= read && read <= 0xEF) {// 也有可能出错，但是几率较小

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;

}