File file = new File("tcp.txt");
FileInputStream stream = new java.io.FileInputStream(file);
int pos =3;//从第几个字节开始读
int len = 1;//读几个字节
stream.skip(pos); //跳过之前的字节数
byte[] b = new byte[len];
stream.read(b);
System.out.print(new String(b));
stream.close();
追问怎样将读取到的字符替换为“1”,并把整个字符串输出?