java 开发实战经典 练习题 第12章 第7题 完成系统登录程序 从命令行输入用户名和密码

import java.util.Scanner;
class LoginOperate{
public void check(){
String args[] = null;
boolean flag = true;
int errCount = 0;
System.out.println("Please enter usr and pwd : ");
Scanner scan = new Scanner(System.in);
while(flag){
if(errCount == 3){
System.out.println("Input error usr or pwd 3 times , system exit ! ");
break;
}
scan.useDelimiter("\n");
String loginStr = scan.next();
args = loginStr.split("\\s");
String username = null;
String password = null;
if(args.length == 2){
username = args[0];
password = args[1];
if("mldn".equals(username) && "hello".equals(password)){
System.out.println("Login successfully，welcome " + username + " back！");
break;
}else {
System.out.println("usr or pwd error");
errCount++;
continue;
}
}else if(args.length == 1){
username = args[0];
System.out.println("Please enter pwd");
errCount++;
continue;
}else{
if(args.length == 0){
System.out.println("Please retype usr and pwd！");
errCount++;
continue;
}
}
scan.close();
System.out.println("errorCounts = " + errCount);
}
}
}
public class TestLoginOperate {
public static void main(String[] args) {
LoginOperate loginOpera = new LoginOperate();
loginOpera.check();
}
}