Java读取txt文件编码格式

File fl=new File("./a.txt");

FileInputStream fis=new FileInputStream(fl);

InputStreamReader isr;

int a = fis.read();

int b = fis.read();
if(a==0xEF&&b==0xBB) {//1 UTF-8

isr=new InputStreamReader(fis,"UTF-8");

} else if(a==0xE6&&b==0xB1) {//2 GBK should use UTF-8
isr=new InputStreamReader(fis,"UTF-8");
} else if(a==0xFE&&b==0xFF){//3 gb2312
isr=new InputStreamReader(fis,"GB2312");
}else if(a==0xFF&&b==0xFE) {//4 Unicode------
isr=new InputStreamReader(fis,"Unicode");
}else{//ANSI use gbk
isr=new InputStreamReader(fis,"GBK");
System.out.println("Can't detect the encode mode!");
}
fis.close();