用IO写一个简单的登录注册功能

public class Login1 {
static Scanner scanner = new Scanner(System.in);
public static void main(String[] args) throws IOException {
while(true) {
System.out.println("请输入a注册，b登录");
String option = scanner.next();
if("a".equalsIgnoreCase(option)) {
reg();
}else if("b".equalsIgnoreCase(option)) {
login();
}else {
System.out.println("你输入有误，请重新输入。");
}
}
}

public static void reg()throws IOException{
System.out.println("请输入帐号：");
String username=scanner.next();
System.out.println("请输入密码：");
String password= scanner.next();
String info = username+" "+password;
File file = new File("F:users.txt");
FileWriter fileWriter = new FileWriter(file,true);

BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
bufferedWriter.write(info);
bufferedWriter.newLine();
bufferedWriter.close();
}

public static void login()throws IOException{
System.out.println("请输入帐号：");
String username=scanner.next();
System.out.println("请输入密码：");
String password= scanner.next();
String info = username+" "+password;

BufferedReader bufferedReader = new BufferedReader(new FileReader("F:\\users.txt"));
String line = null;

boolean isLogin = false; 
while((line = bufferedReader.readLine())!=null) {
if(info.equals(line)) {
isLogin =  true;
break;
}
}

if(isLogin) {
System.out.println("登录成功！");
}else {
System.out.println("你的帐号或密码有误，请重新输入！");
}

}

}